L.O 3.33: The student is able to use representations and
appropriate models to describe features of a cell signaling
pathway. SP 1.4: The student can use representations and models to
analyze solutions or solve problems qualitatively and
quantitatively. Explanation: In a cell there is a 3 stage process
of cell signaling that occurs. First, reception occurs, which is
when a ligand (a signal molecule) binds to a receptor that is
membrane bound or inside the cell. There are 4 different types of
receptors that a ligand can bind to depending on the specific
communication that needs to take place: intracellular receptors or
steroid hormone receptors, g- protein-linked receptors, tyrosine
kinase receptors, and ligand-gated ion channels. Once the ligand
has binded to the receptor the next process, transduction, occurs.
Here, the conversion of the received signal to a cellular response
takes place. This is mainly done by protein phosphorylations such
as once a receptor is activated it phosphorylates protein kinases
and other relay molecules (2 nd messengers) within the cell, to aid
in the signaling pathway to a cell response. Different proteins are
activated through this process to help relay a particular cellular
response. In the 3 rd process, response, the transduced signal
finally triggers a specific cellular response and this 3 stage
process is repeated until the body is no longer in need of that
response. An example of this signaling pathway is found commonly
with hormones. When blood sugar levels rise in the body, the
pancreas releases insulin, which then travels to the liver cells
and binds to them. This signal into the liver cells creates a
response to the store the sugar as glycogen thus dropping the blood
sugar level back to normal allowing for homeostasis to be
maintained within the body. Multiple Choice: The binding of a
signaling molecule to which type of receptor leads to a change in
distribution of ions on opposite sides of the membrane? a. tyrosine
kinase receptor b.G protein-linked receptor c.phosphorylated
tyrosine kinase receptor dimer d.ligand-gated ion channel
e.intracellular receptor FRQ-style question: The relationship of
structure to function is essential throughout biological topics.
Specifically describe the Structure of a cell membrane and how
signal transduction is related.
Slide 2
Answer Key- L.O. 3.33 The binding of a signaling molecule to
which type of receptor leads to a change in distribution of ions on
opposite sides of the membrane? a. tyrosine kinase receptor b.G
protein-linked receptor c.phosphorylated tyrosine kinase receptor
dimer d.ligand-gated ion channel e.intracellular receptor The
relationship of structure to function is essential throughout
biological topics. Specifically describe the structure of a cell
membrane and how signal transduction is related. The cell membrane
is composed of a phospholipid bilayer that incorporates integral
proteins. There are also membrane-bounded receptor molecules within
the cell membrane to aid in the process of signal transduction.
When a stimulus is present receptor proteins undergo shape changes
as the signal is communicated through the membrane by shape change.
The altered proteins then can have influence on other cellular
processes as it could activate g-proteins or tyrosine-kinase
receptor proteins phosphorylations thus creating a cellular
response.
Slide 3
LO 3.18: The Student is able to describe the connection between
the regulation of gene expression and observed differences between
different kinds of organisms. SP 7.1: The student can connect
phenomena and models across spatial and temporal scales.
Explanation: Even though an individuals cells have the same DNA
sequences, each cell has different segments of DNA being expressed.
Each segment codes for a different gene. In order to initiate
transcription of a specific gene, polymerase binds to the DNA with
the aid of transcription factors. These factors are important,
because only once they have been assembled, can the polymerase
begin producing a complimentary RNA strand. Enhancers are a
transcription factor that may be located thousands of nucleotides
away from a gene. A gene may have multiple enhancers that can be
activated at different times, or in different cells types. An
activator is a protein that binds to an enhancer and stimulates
transcription of a gene. Some transcription factors are repressors,
which inhibit gene expression by blocking the binding of
activators. Activators and repressors can also act indirectly by
influencing chromatin structure, such as attracting proteins that
acetylate histones near promotors of genes, which leads to
transcription. Transcription depends on the binding of activators
to DNA control elements. There are only about a dozen nucleotide
sequences that appear in control elements for different genes. Each
enhancer is usually composed of about ten control elements, each of
which bind to one transcription factor. Each combination of control
elements in an enhancer associated with a gene is more important
than the presence of a single unique control element. The specific
transcription factors determine which genes are expressed in a
cell. An example occurs between the liver cell and lens cell
because both cells have genes for the proteins albumin and
crystallin. However, the liver cell has specific activators that
will bind to an enhancer that transcribes only the albumin gene;
while the lens cell has different activators that match up with a
different enhancer that leads to the expression of only the
crystallin gene. Learning Log/ FRQ-Style Question: Activators and
repressors are both different types of proteins that can control
gene expression. Tell what the role of each is and describe the how
each of these can lead to the expression of a specific gene.
Enhancer Promoter Control elements Albumin gene Crystallin gene
Liver cell nucleus Lens cell nucleus Available activators Available
activators Albumin gene expressed Albumin gene not expressed
Crystallin gene not expressed Crystallin gene expressed Liver
cellLens cell (a) (b) M.C. Question: Which of the following is NOT
true when talking about how gene expression is regulated in a
particular cell? A)The activator that binds to a specific enhancer
determines which genes will be transcribed. B)The specific control
elements within the enhancer are more important then the
combination of control elements that an activator binds to. C)An
activator must first bind to an enhancer before general
transcription factors such as RNA polymerase can bind to the
promotor. D)A repressor can bind to a separate enhancer which can
terminate transcription even if activators are present.
Slide 4
ANSWER KEY LO-3.18 An activator is a protein that binds to an
enhancer and will stimulate transcription. Activators are able to
bind to distal control elements that are not close to the promotor.
When an activator binds to an enhancer, protein-mediated bending of
the DNA occurs. This allows the bound activators to come in contact
with other transcription initiating proteins called mediator
proteins. All these proteins together then interact with the
promotor and allow for the binding of RNA polymerase II which
initiates transcription of a particular gene. A repressor is a
protein that inhibits the expression of a specific gene. One way a
repressor can inhibit expression is by blocking activators from
binding to control elements or to any proteins that are involved in
transcription. Repressors can also bind directly to their own
enhancer and can turn off transcription even in the presence of
activators. Activators and repressors are both different types of
proteins that can control gene expression. Tell what the role of
each is and describe how each of these can lead to the expression
of a specific gene. Which of the following is NOT true when talking
about how gene expression is regulated in a particular cell? A)The
activator that binds to a specific enhancer determines which genes
will be transcribed. B)The specific control elements within the
enhancer are more important then the combination of control
elements the an activator binds to. C)An activator must first bind
to an enhancer before general transcription factors such as RNA
polymerase can bind to the promotor. D)A repressor can bind to a
separate enhancer which can terminate transcription even if
activators are present. Distal control element Activat ors Enhanc
er Promot er Ge ne TAT A box General transcripti on factors DNA-
bending protein Group of Mediator proteins RNA Polymeras e II RNA
Polymeras e II RNA synthesis Transcription Initiation complex
Chromatin changes Transcrip tion RNA processing mRNA degrada tion
Transla tion Protein processing and degradation A DNA-bending
protein brings the bound activators closer to the promoter. Other
transcription factors, mediator proteins, and RNA polymerase are
nearby. 2 Activator proteins bind to distal control elements
grouped as an enhancer in the DNA. This enhancer has three binding
sites. 1 The activators bind to certain general transcription
factors and mediator proteins, helping them form an active
transcription initiation complex on the promoter. 3
Slide 5
LO 4.3: The student is able to use models to predict and
justify that changes in the subcomponents of a biological polymer
affect the functionality of the molecule. SP 6.1: The student can
justify claims with evidence. SP 6.4: The student can make claims
and predictions about natural phenomena based on scientific
theories and models. Explanation: Changes in the monomers of a
biological polymer affect its shape and therefore its function. The
properties of each monomer are critically important to the function
of the polymer. For example, the amino acids of a protein are
categorized by how they react to water: hydrophilic or hydrophobic.
They are also categorized by the type of bonds they form. Each
amino acid has an R-group that determines its structure and thus
its function. A notable example in this case are enzymes; enzymes
are proteins that need to be a specific shape in order to properly
conduct its biological activities. If an enzymes amino acids do not
interact in a way that forms it into its specific lock shape, the
enzyme will be rendered ineffective. A denatured enzyme is a broken
enzyme that will not catalyze a substrate due to pH/temperature
changes in the environment. These pH/temperature changes result in
broken bonds in the amino acids, which change the shape in the
primary, secondary, tertiary, or quaternary structures. Example
M.C. Question: Which of the following properties allows a steroid
to move into a cell and bind to a steroid receptor? A. steroids are
polar, which allows them to bind to proteins in the membrane to
diffuse through the cellular membrane. B. steroids are non-polar,
which allows them to freely move through the phospholipid bilayer
into the cell. C. steroids are saturated, so they bind to enzymes
that break down a small part of the membrane and push the steroid
through the membrane. D. steroids are unsaturated, so they move
through ligand-gated ion channels. Example FRQ Question: Suppose
you conduct an experiment in which you place Enzyme A into a test
tube with its proper substrate. You place Enzyme B into a different
test tube with its proper substrate as well. You measure the number
of reactions in each test tube at 20 degrees Celsius for three
minutes and record that 40 grams of product A was found in the
first test tube. 43 grams of product B was found in the second test
tube. You conduct a second experiment, raising the temperature to
40 degrees Celsius. You find that 38 grams of product A was found
in the first test tube. 3 grams of product B was found in the
second test tube. What can you conclude about the enzymes?
Slide 6
Which of the following properties allows a steroid to move into
a cell and bind to a steroid receptor? A. steroids are polar, which
allows them to bind to proteins in the membrane to diffuse through
the cellular membrane. B. steroids are non-polar, which allows them
to freely move through the phospholipid bilayer into the cell. C.
steroids are saturated, so they bind to enzymes that break down a
small part of the membrane and push the steroid through the
membrane. D. steroids are unsaturated, so they move through
ligand-gated ion channels. Explanation: Answer choice A is not
correct because steroids are not polar. Answer choice C and D or
not correct because the saturation/unsaturation of steroids do not
affect whether or not the molecule can move through the
phospholipid bilayer. Answer choice B is correct because non-polar
substances that are a) accepted by the cell and b) small enough to
move through the cellular membrane can freely move through the
phospholipid bilayer, as the monomers of the steroid do not attract
it to any other substance. Example FRQ Question: Suppose you
conduct an experiment in which you place Enzyme A into a test tube
with its proper substrate. You place Enzyme B into a different test
tube with its proper substrate as well. You measure the number of
reactions in each test tube at 20 degrees Celsius for three minutes
and record that 40 grams of product A was found in the first test
tube. 43 grams of product B was found in the second test tube. You
conduct a second experiment, raising the temperature to 40 degrees
Celsius. You find that 38 grams of product A was found in the first
test tube. 3 grams of product B was found in the second test tube.
What can you conclude about the enzymes? Explanation: Enzyme A and
Enzyme B are both effective at catalyzing reactions at room
temperature. However, enzyme A is still effective at catalyzing
reactions at high temperatures, while enzyme B is not. Enzyme A
must consist of amino acids with strong bonds that do not easily
denature. The structure of enzyme A during the second experiment
remained the same as the first experiment. This did not hold true
for enzyme B; its amino acids did not maintain the same structure
at a high temperature, because the rate of reaction was much lower.
The amount of catalyzed substrate reflects that the shape of the
substrate could not fit the shape of enzyme B during the second
experiment, which obviously denatured. This experiment exemplifies
that the shape of the enzyme plays a critical role in the
reaction.
Slide 7
LO 3.14: The student is able to apply mathematical routines to
determine Mendelian patterns of inheritance. SP 2.2:The student can
apply mathematical routines to quantities that describe natural
phenomena. Explanation: Through his research, Mendel was able to
determine that there are two different traits that can be expressed
by an organism, which we call alleles. He called these alleles
dominant and recessive. Mendel determined that every organism has
two alleles, if an organism had two dominant alleles, it was known
as homozygous dominant. If an organism had two recessive alleles,
it was known as homozygous recessive. Mendel took his experiment
farther when he crossed two true breeding flowers, one homozygous
dominant and one homozygous recessive. What he noticed was that all
the F1 generation all expressed the dominant allele but not all of
the plants could be homozygous dominant because when you cross the
two true breeding flowers, each of the progeny will have one
dominant allele and one recessive allele. What Mendel determined
was that an organism can express the dominant allele while also
carrying the recessive allele, he called this discovery being
heterozygous(Pp) for a trait. With this knowledge, Mendel was able
to predict possible outcomes for the offspring of a particular
generation. Multiple Choice: Susan and Joe are going to have a
child. Susan is a carrier of the sickle cell allele and Joe is
homozygous dominant for the sickle cell allele. What is the
probability that Susan and Joe will have a child with sickle cell?
a)1 c) b)0 d) FRQ: A new species of insect has been found on an
island off the coast of South America. Scientists have concluded
that black body is dominant to bronze body and normal wings are
dominant to vestigial wings. Scientists crossed two insects, one
homozygous dominant for black body, normal wings and one homozygous
recessive for bronze body, vestigial wings. All the F1 offspring
had black body, normal wings. Two F1 offspring were crossed and the
information for the F2 offspring are as follows: 263 black body,
normal wings, 233 bronze body, vestigial wings, 85 black body,
vestigial wings, and 42 bronze body, normal wings. a)Find the
recombination frequency of the F2 offspring using the recombination
frequency formula, round to the nearest tenth and make sure to show
your work. Also, using the recombination frequency, determine how
many map units the recombinant genes are from each other, explain
your answer. b)Using your knowledge of Mendelian patterns of
inheritance, explain why the F1 offspring only expressed the two
dominant traits while the F2 offspring expressed both the dominant
and recessive traits.
Slide 8
Answer Key Slide Multiple Choice: Susan and Joe are going to
have a child. Susan is a carrier of the sickle cell allele and Joe
is homozygous dominant for the sickle cell allele. What is the
probability that Susan and Joe will have a child with sickle cell?
a)1 b)0 c) d) FRQ: a)RF= 127/623(100) RF=20.4% The recombinant
genes will be 20.4 map units apart. We can determine this because
one map unit is equal to 1% recombination frequency. b) The F1
offspring only express the two dominant traits because when you
cross two true breeding insects as the parental generation are, the
offspring obtain one copy of the dominant allele and one copy of
the recessive allele for body color and one copy of the dominant
allele and one copy of the recessive allele for wing shape.
However, based on Mendelian patterns of inheritance, we know that
the F1 progeny will be heterozygous, expressing the dominant allele
gained from one parent while also being a carrier of the recessive
allele. However, when we cross the two heterozygous F1 offspring,
we know that because of Mendelian patterns of inheritance, there
will be some organisms who will have to express the recessive
traits based on scientific knowledge.
Slide 9
Learning Objective: 1.14 The student is able to pose scientific
questions that correctly identify essential properties of shared,
core life processes that provide insights into the history of life
on Earth. Science Practice: 3.1 The student can engage in
scientific questioning to extend thinking or to guide
investigations within the context of the AP course. 3.1: Student
can pose scientific questions. Explanation: The origin and history
of life on Earth is constantly under debate. Organisms today share
multiple core processes and features, this provides evidence that
the complex organisms today could be derived from one common
ancestor. The process of evolution explains how the incredibly
diverse array of organisms could have originated from one universal
ancestor. DNA and RNA carry genetic information in all organisms.
These features of the genetic code can be found in all modern
living systems. In eukaryotes, specifically, features like the
cytoskeleton, membrane- bound organelles, a nucleus, endomembrane
systems, and linear chromosomes are all core elements. Though
evolution is widely viewed as a theory we lack an explanation of
how these features could have been created separately or
independently of one and other. The common core life processes
found provide evidence that the history of life on Earth involves
the evolution of complex and diverse live systems from one common
or universal ancestor. Phylogenetic trees can help us visualize and
estimate in what order species diverged from the common ancestor.
Multiple Choice: All of the following factors provide evidence to
support the theory that all living systems derive from one common
ancestor EXCEPT: a. The universal existence of DNA and RNA in
organisms. b. Membrane-bound organelles in eukaryotes. c. When life
began the Earth was not stable enough to house more than one
original common ancestor. d. Homologous structures found throughout
multiple species. Free Response Question: a. Evolution from a
common ancestor is said to explain the diverse and sometimes
similar nature of Earth's species. Discuss two pieces of evidence
that support this theory. b. Thinking in terms of this theory, if
two species are structurally similar- are they more likely to have
more recently shared a common ancestor or diverged from the
ancestor longer ago?
Slide 10
Answer Key LO 1.14 Multiple Choice: All of the following
factors provide reliable evidence to support the theory that all
living systems derive from one common ancestor EXCEPT: a. The
universal existence of DNA and RNA in organisms. b. Membrane-bound
organelles in eukaryotes. c. When life began the Earth was not
stable enough to house more than one original common ancestor. d.
Homologous structures found throughout multiple species. Free
Response Question: a. Evolution from a common ancestor is said to
explain the diverse and sometimes similar nature of Earth's
species. Discuss two pieces of evidence that support this theory.
b. Thinking in terms of this theory, if two species are
structurally similar- are they more likely to have more recently
shared a common ancestor or diverged from the ancestor longer ago?
a. Universal features found in eukaryotes like the cytoskeleton and
membrane bound organelles support the theory that life came from
one common ancestor. These traits are universal and it is likely
that they were passed on through each generation from one shared
relative. The fact that DNA and RNA are also used to carry genetic
information in all living systems also supports this claim, because
it is used in all life systems. b. If two species share a similar
structure and homologous features, then it is more likely that they
more recently shared a common ancestor. This way, there would be
less time for the separate species to evolve different traits.
Slide 11
LO 2.31: The student can connect concepts in and across domains
to show that timing and coordination of specific events are
necessary for normal development in an organism and that these
events are regulated multiple mechanisms. SP 7.2: The student can
connect concepts in and across domains Explanation: In developing
embryos, it is necessary for events to occur correctly by gene
differentiation in order not to cause abnormalities in offspring.
Once fertilized, the zygote replicates in to a clump of cells
called a blastula. These cells have homeotic genes, which determine
developmental patterns. The expression of certain genes lead to the
development of different parts of the embryo. For example, Bicoid
determines the posterior side of an embryo to determine where the
head and feet go. From this point, a digestive tract is developed,
called gastrulation. Morphogenesis plays the role of shaping parts
of the body of the embryo such as the organs and appendages.
Apoptosis, or programed cell death, aids in this development by
killing cells that are unnecessary after certain checkpoints in
development, such as formation of fingers and toes. M.C. Question:
While testing gene expression, a early developing drosophila is
injected with bicoid equally into both sides of the embryo. What
result is most likely to occur? A) The drosophila will develop
normally B) Apoptosis will occur to kill the extra bicoid cells and
form both the head and tail of the embryo. C) The drosophila would
develop two heads and die. D) Bicoid is not necessary in the
development of drosophila. Learning Log/ FRQ- Style Question: While
in the womb, human embryos develop webbing on their hands and feet
as well as gills. In most cases, these features are not present in
the offspring at time of birth. Why are these traits essential for
the development timeline? What mechanism regulates the removal of
webbing and gills and why is this important to the development of
the embryo?
Slide 12
Answer Key- L.O. 2.31 While testing gene expression, a early
developing drosophila is injected with bicoid equally into both
sides of the embryo. What result is most likely to occur? A) The
drosophila embryo will develop normally B) Apoptosis will occur to
kill the extra bicoid cells and form both the head and tail of the
embryo C) The drosophila embryo would develop two heads and die D)
Bicoid is not necessary in the development of drosophila embryo
While in the womb, human embryos develop webbing on their hands and
feet as well as gills. In most cases, these features are not
present in the offspring at time of birth. Why are these traits
essential for the development timeline? What mechanism regulates
the removal of webbing and gills and why is this important to the
development of the embryo? The formation of gills and webbing are
important in development so that the embryo can survive in the
aqueous environment of the mothers womb. As the fetus approaches
due date, lungs will begin to develop through morphogenesis.
Apoptosis will then kill the webbing and gill cells. In the hands
and feet, morphogenesis will aid the final formation of the fingers
and toes. Around the neck, the gill slits will be fused together.
If development does not continue correctly, a human baby can be
born with webbing or non-functional gills, both of which will not
affect their life drastically.
Slide 13
LO 1.13: The student is able to construct /or justify
mathematical models, diagrams or simulations that represent
processes of biological evolution. SP 1.1/2.1: (1.1) The student
can create representations and models of natural or man made
phenomena and systems in the domain. (2.1)The student can justify
the selection of mathematical routine to solve problems.
Explanation: In evolution phenotype expression is determined by the
organisms combination of alleles for a certain genotype. A simple
way of calculating the chance of a phenotype outcome/expression in
a population is to use a Hardy- Weinberg equilibrium equation. The
equation is p + 2pq + q = 1(as well as p+q=1). p represents the
allelic frequency of dominant alleles in a population, while q
represents the allelic frequency or recessive alleles, and pq is
the heterozygous frequency. A Hardy-Weinberg test can be used to
calculate such phenomena as a chance of a hereditary disease
spreading in a population of organisms, as well as display this
information in a model such as the picture in the bottom right.
Another model that can be used to calculate the evolution of traits
would be a punnett square. In epigenetics a punnett square is
important in predicting the phenotype/genotype of a couples
offspring. It can also be used to determine the biological
evolution of a population depending on who they mate with.
(Pictures below.) M.C. Question: If a Colorblind male mates with a
homozygous female who has a single Barr body on one of her X
chromosomes. What is the likelihood of their child having
colorblindness ? A) 50% because colorblindness is only found in
males B) 25% if they are male and 0% if they are female. The Barr
body in a female will not Affect the crossing C) 0% because
colorblindness is recessive and the off spring would only have X^C
Y And X^C X^c D)75% because the addition of the Barr body when it
is activated could possibly result In 3/4ths of the children
expressing colorblindness. Learning Log/FRQ-style Question: Maria
wants to have a child with Tyrone, but she is afraid that their
child will get Hemophilia like her mother. Maria doesnt express
Hemophilia. She discovered that Tyrones grandmother on his moms
side had hemophilia but his mom doesnt.(his dads side has no
history of it) What is the likelihood their child will have the
disorder? Also explain your reason for this conclusion and include
a punnett square and a pedigree.
Slide 14
ANSWER KEY LO 1.13 If a Colorblind male mates with a homozygous
female who has a single Barr body on one of her X chromosomes. What
is the likelihood of their child having colorblindness ? A) 50%
because colorblindness is only found in males B) 25% if they are
male and 0% if they are female. The Barr body in a female will not
Affect the crossing C) 0% because colorblindness is recessive and
the off spring would only have X^C Y And X^C X^c D)75% because the
addition of the Barr body when it is activated could possibly
result In 3/4ths of the children expressing colorblindness. (side
note: The fact it says Barr Body is meant to trick the student. All
Females with XX Chromosomes only express one X and the other one is
a Barr body) (sample drawing) FRQ: Maria wants to have a child with
Tyrone, but she is afraid that their child will get Hemophilia like
her mother. Maria doesnt express Hemophilia. She discovered that
Tyrones grandmother on his moms side had hemophilia but his mom
doesnt.(his dads side has no history of it) What is the likelihood
their child will have the disorder? Also explain your reason for
this conclusion and include a punnett square and a pedigree. The
likely hood of her child having hemophilia is about 25%. This is
due to the fact that Tyrones mom being a carrier has no affect on
his offspring because he does not have it and can not give it. But
Maria being a carrier does affect the chance. Like in the sample
drawing. The punnett square should resemble the one to the left.
The pedigree should resemble the image in the top right.
Slide 15
Biology Review PPT Slide Learning Objective 3.11 : The student
is able to evaluate evidence provided by data sets to support the
claim that heritable information is passed from one generation to
another generation through mitosis, or meiosis followed by
fertilization. Connected Science Practice 5.3 : The student can
evaluate the evidence provided by data sets in relation to a
particular scientific question. Explanation: If a student is given
a data set showing how a certain trait was passed on to the next
generation, they should be able to read and understand the data and
then use the information given to either answer questions or
confirm/refute statements about whether or not heritable
information was passed on through mitosis or meiosis and
fertilization in a specific case. In order to do this, the student
should have a good understanding of the process of mitosis and
meiosis/fertilization, how genetic variation may or may not result
from each one, and how that happens through processes like
independent assortment, crossing over, mutations. etc. They should
also be familiar with the haploid and diploid stages of
mitosis/meiosis and have a good understanding of the cell cycle.
For example, if the data set given, such as a punnett square, shows
that a mother and father gave alleles to their children via sexual
reproduction, the student would be able to assume that, since
reproduction needed two haploid cells each with a different allele
to join and produce a diploid zygote, meiosis, which results in
four haploid cells, and fertilization occurred to produce the baby.
If the data showed that the baby had the same DNA and therefore the
same alleles and phenotypes as a single parent organism, the
student should know that mitosis took place to pass on the genes of
the parent and produce a clone. Example Multiple Choice Question:
Using the pedigree to the left, how can one tell that the autosomal
recessive disorder was passed down through the generations via
meiosis and fertilization rather then a behavior learned by
offspring from their parents? A) All affected children have at
least one parent who is also affected and unaffected couples have
no affected offspring. B)Not all of the offspring in the second
generation are affected even though both of their parents were
affected. This can only happen because meiosis and fertilization
produce four different gametes that can combine to form zygotes
with different allele frequencies. C)The only homozygous recessive
person is male meaning that the disorder is X- linked and therefore
meiosis must be involved in passing the gene on to the next
generation. D) There is no way to know this without further
information. Example Essay Question: Using the data set to the
left, explain how the pedigree would look different it mitosis were
the process used for reproduction instead of meiosis and why.
Slide 16
Example Multiple Choice Question: Using the pedigree to the
left, how can one tell that the autosomal recessive disorder was
passed down through the generations via meiosis and fertilization
rather then a behavior learned by offspring from their parents? A)
All affected children have at least one parent who is also affected
and unaffected couples have no affected offspring. B)Not all of the
offspring in the second generation are affected even though both of
their parents were affected. This can only happen because meiosis
and fertilization produce four different gametes that can combine
to form zygotes with different allele frequencies. C)The only
homozygous recessive person is male meaning that the disorder is
X-linked and therefore meiosis must be involved in passing the gene
on to the next generation. D) There is no way to know this without
further information. Example Essay Question: Using the data set to
the left, explain how the pedigree would look different if mitosis
were the process used for reproduction instead of meiosis. If the
mitosis were the process used for reproduction instead of meiosis,
then each offspring would only have one parent because mitosis is
an asexual form of reproduction. Meiosis results in four, haploid,
different daughter cells, that combine called a gamete with another
gamete from the other parent to produce offspring with entirely
unique genetic sequences. However, when a cell goes through
mitosis, it first begins growing and replicating its DNA, the DNA
winds into chromosomes and lines up single file while the nucleus
disappears and other organelles are copied and split between two
sides of the cell. Spindle fibers extend from each side of the cell
and attach to centromeres in the middle of each chromosome. The
chromosomes are torn in half and pulled to opposite ends of the
cell, the nucleus reforms and the cell splits into two daughter
cells. Each of these cells are clones of the parent cell. Leaving
little room for genetic variation. So, in the pedigree, each of the
offspring would be exact clones of their parent, so all of the
individuals in the pedigree would have the same genotype and
phenotype. The only way one could have a different genotype would
be if that organism had a mutation in its DNA causing it to have a
different trait then the others. This organism might then pass this
trait on to its offspring and they would likely have it too because
they would be clones of the cell with the mutation.
Slide 17
A) LO 4.17: The student is able to analyze data to identify how
molecular interactions affect structure and function. B) SP 5.1:
The student can analyze data to identify patterns or relationships.
C) Carrying out a variety of functions in the body, proteins are
complex macromolecules whose structure and function are determined
by molecular interactions. Each protein has a unique shape and
function that is determined by the different levels of structure.
While all proteins have a primary, secondary, and tertiary
structure, not all have a quaternary structure in which the protein
is composed of more than one polypeptide chain. The primary
structure of a protein is its own unique sequence of amino acids.
It is then the secondary structure, in which the polypeptide is
coiled/foiled into either an alpha helix or a beta pleated sheet
depending on the hydrogen bonding within the polypeptide chain. The
tertiary structure is the three-dimensional shape of the protein;
it is then this three-dimensional shape that is superimposed on the
proteins secondary structure that determines the proteins
specificity. A proteins resulting tertiary structure is influenced
by factors such as the hydrogen bonding, ionic bonding, hydrophobic
interactions, Van der Waals interactions, and disulfide bonds. Such
factors determine how each polypeptide wraps around or bonds to
itself to create a three-dimensional shape that is unique to that
protein. The uniqueness of each protein is constricts to serve only
its specified function within the body. Examples of unique proteins
and their functions are in enzymatic activity and in transduction
pathways. Enzymes are round(ish )proteins that exhibit tertiary
structure. Each enzyme have its complementary substrate and will
only bind to that complementary substrate; once an enzyme binds to
its proper substrate, it is activated and catalyzes a reaction. In
transduction pathways, the pathway is only initiated if the correct
ligand binds to the substrate at the beginning of the pathway. D)
In an experiment, a protein is combined with a denaturing solvent
that disrupts the molecular interactions that are holding it
together. Once the protein is denatured, it losses its
three-dimensional shape and becomes a flexible polypeptide chain.
When the denaturing solvent is removed, the protein refolds itself
into its original shape before being denatured. This experiment
concludes that a. the three-dimensional shape of a protein is
determined by a denaturing solvent b. the three-dimensional shape
of a protein is based on its primary structure which consists of
its amino acid sequence c. the three-dimensional shape of a protein
is completely randomized d.the three-dimensional shape of a protein
is unaffected by its primary and secondary structures and is solely
influenced by the its interactions with outside elements E) The
following image depicts a portion of a polypeptide that is
arranging itself into its tertiary structure through various
molecular interactions. Identify each labeled interaction and
determine how it affects the shape of the protein that is in the
process of being formed. A C D B
Slide 18
Answer Key LO: 4.17 D) In an experiment, a protein is combined
with a denaturing solvent that disrupts the molecular interactions
that are holding it together. Once the protein is denatured, it
losses its three-dimensional shape and becomes a flexible
polypeptide chain. When the denaturing solvent is removed, the
protein refolds itself into its original shape before being
denatured. This experiment concludes that a. the three-dimensional
shape of a protein is determined by a denaturing solvent b. the
three-dimensional shape of a protein is based on its primary
structure which consists of its amino acid sequence c. the
three-dimensional shape of a protein is completely randomized d.the
three-dimensional shape of a protein is unaffected by its primary
and secondary structures and is solely influenced by the its
interactions with outside elements E) The following image depicts a
portion of a polypeptide that is arranging itself into its tertiary
structure through various molecular interactions. Discuss the
specific interactions at each labeled part. A C D B Point A
exhibits hydrophobic and Van der Walls interactions. At such
interactions, hydrophobic side chains cluster at the center of the
protein so that they are as far away as possible from the water and
other polar molecules that surround the protein. When non-polar
amino acid side chains are within close proximity to one another,
they are then held together by van der Waals interactions. Point B
is an example of a hydrogen bond in which polar side chains are
joined together. At point C two amino acid side chains are brought
together by their sulfhydryl groups to form a disulfide bridge. At
point D, portions of the polypeptide chain is brought together by
an ionic bond formed between a positively charged side chain and a
negatively charged one.
Slide 19
LO 1.12: The student is able to connect scientific evidence
from many scientific discipline to support the modern concept of
evolution. SP 7.1: The student can connect phenomena and models
across spatial and temporal scales. The commonly supported Darwin
view of evolution states that evolution is the change of gene
frequencies in the gene pool of a population over many generations.
This can happen when species are separated from one another (due to
ecological or other barriers,) and the alleles offspring receive
from the parents are mutated due to recombination and genetic
variation. Natural selection then selects these favorable traits
and due to survival of the fittest these organisms with the
beneficial selected traits are able to reproduce and pass the trait
on to their offspring. The change of allele frequencies though
largely due to natural selection, can also be from isolation and
restriction of gene flow between the parent and offspring resulting
in divergent evolution. Examples of these forms of evolution can be
seen in the molecular biology of DNA, comparative embryology, and
the biogeography of fossils. Molecular evolution, has shown that
all living organisms, ranging from bacteria to human, are related
to common ancestors. The DNA coding sequences that transcribe
proteins, and enzymes can be compared to other DNA sequences using
DNA libraries to determine the last shared common ancestor. This
can be used to determine both ancient relationships and recent
ones. Comparative embryology proves evolution, because although
many species look very different in adult form, most often have
very similar embryos. These common embryos prove that all species
shared common ancestors, because the serial structures are
identical in the embryo, but specialized and diverged as an adult.
The theory of evolution is also supported by biogeography.
Identical plant and animal fossils have been located on opposite
sides of the globe. This is due to the process of natural selection
and illustrates both convergent and divergent evolution. Convergent
evolution, where organism not closely related develop the same
traits due to their environment, can be shown by the fossils of
sugar gliders and flying squirrels, that are on opposite
continents, but due to natural selection and genetic mutation
evolved with the same traits. Divergent evolution can also be
proved by fossils and is shown in humans, horses, cats, and birds
that all shared a common ancestor because they all have the same
arm bones. Multiple Choice: Structures that are as different as
human arms, whale flippers, and horse legs have been found to have
many similar bones that developed from very similar embryonic
tissues. How can it be proved these structures are related? A)
Using the definition of homologous structures B) Because of
convergent evolution C) Because humans, whales, and horses share a
common ancestor D) All of the above E) A and C are correct
Essential Question: Evolution as defined by Darwin is the change of
gene pool frequencies in a gene pool over many generations. Choose
and explain THREE ways scientist can prove and support this
idea.
Slide 20
ANSWER KEY- LO 1.12 Structures from organisms as different as
human arms, whale flippers, and horse legs have many similar bones
that developed from very similar embryonic tissues. How can it be
supported/ proved these structures are related? A) by identifying
the bones as being homologous structures B) by the principle of
convergent evolution C) by proposing that humans, bats, and
dolphins share a common ancestor D) All of the above E) A and C are
correct Evolution as defined by Darwin is the change of gene pool
frequencies in a gene pool over many generations. Choose and
explain THREE ways scientist can prove and support this idea.
Scientists can support this idea using the three scientific
disciplines: embryology, biogeography of fossils, and the molecular
biology of DNA. In the embryo the serial structures of almost all
organisms are nearly identical, which cannot be said once they have
developed as adults. Using comparative embryology, the similarity
in structure supports the idea that they share a common ancestor,
and developed through evolution. The biogeography of fossils can be
used to support the idea of convergent evolution. For species like
the flying squirrel and sugar gliders, though they live on separate
continents due to genetic mutations, and similar ecosystem
pressures they have adapted similar structures. By comparing their
fossils, scientists can pinpoint these genetic mutations and track
the evolution of the species. The molecular biology of DNA, shows
the closely related base sequences of many organisms. These similar
nucleotide sequences identify common ancestors, which can easily be
located using genomic libraries, as scientists can compare and
evaluate the evolution of species from these common ancestors.
Slide 21
A.LO 2.10 The student is able to use representations and models
to pose scientific questions about the properties of cell membranes
and selective permeability based on molecular structure. [See SP
1.4, 3.1] B.SP 1.4 The student can use representations and models
to analyze situations or solve problems qualitatively and
quantitatively. SP 3.1 The student can pose scientific questions.
C.Explanation Cell membranes are important for cell life and
activity because they regulate transport across cellular
boundaries. For instance, cells take in oxygen to use for cellular
respiration and then release carbon dioxide. Cell membranes are
selectively permeable, meaning that they allow some substances to
cross more easily than others. The cell membrane is made primarily
of lipids and proteins. The greatest amount of lipids are
phospholipids, which make the phospholipid bilayer. Phospholipids
are amphipathic molecules, meaning that they have a hydrophilic
(polar) head which is exposed to the aqueous solution on either
side of the membrane, and a hydrophobic (nonpolar) tail which is
contained in the middle of the bilayer. The exterior proteins,
parts of proteins, and carbohydrate side chains are also polar
while inner proteins are nonpolar. The dispersal of proteins in the
phospholipid bilayer is known as the fluid mosaic model for
membranes. Hydrophobic (nonpolar) molecules, such as hydrocarbons,
carbon dioxide, and oxygen, can cross the membrane with ease
through the process of diffusion. However, hydrophilic (polar)
molecules, such as glucose, other sugars, and even water, have a
difficult time diffusing through the hydrophobic (nonpolar) core of
the membrane. These molecules cannot cross the membrane as rapidly
as nonpolar molecules. The membrane is even more difficult to pass
through for charged atoms or molecules. In order for these ions and
other polar molecules to pass through the membrane, they must pass
through a transport protein that has a polar channel that the ions
and polar molecules use as a tunnel to enter the cell. For
instance, the passage of water into and out of a cell is made
possible by channel proteins called aquaporins. Also carrier
proteins aid in diffusing polar molecules into the cell. The use of
channel proteins or carrier proteins or the simple diffusion of
nonpolar substances across the plasma membrane is known as passive
transport. Passive transport occurs when molecules move down their
concentration gradient (from high concentration to low
concentration). D.Multiple Choice Question In a eukaryotic cell,
which of the following molecules would require the use of a channel
protein in order to enter the cell? A. Hydrocarbon B. Sucrose C.
Iodine D. Estrogen E.Free Response Question Certain properties of
cell membranes make them permeable to some molecules while
impermeable to others. Explain the cell membrane structure and
chemical properties that allow for this discrepancy. Provide an
example of a molecule that would and a molecule that would not be
able to permeate a cell membrane based on the chemical properties
you described above. Passive transport Diffusion Facilitated
diffusion Hydrophilic head Hydrophobic tail WATER
Slide 22
Multiple Choice Question In a eukaryotic cell, which of the
following molecules would require the use of a channel protein in
order to enter the cell? A. Hydrocarbon B. Sucrose C. Iodine D.
Estrogen Multiple Choice Answer: B. Sucrose. The three other answer
choices (hydrocarbon, iodine, and estrogen) are nonpolar molecules
so they would be able to use simple diffusion to permeate the cell
membrane. Sucrose, a sugar, is polar, thus requiring a channel
protein to permeate the cell membrane. Free Response Question
Certain properties of cell membranes make them permeable to some
molecules while impermeable to others. Explain the cell membrane
structure and chemical properties that allow for this discrepancy.
Provide an example of a molecule that would and a molecule that
would not be able to permeate a cell membrane based on the chemical
properties you described above. FRQ Model Answer: Cell membranes
are made of phospholipids (1). A unique chemical property of
phospholipids is their polar head, which is exposed to the interior
and exterior of the cell, and their nonpolar tail, which is in the
interior of the membrane (1). These chemical properties make it
easy for nonpolar molecules to diffuse through the cell
membrane(1). However, the nonpolar core makes it difficult for
polar molecules to diffuse through the membrane(1). An example of a
nonpolar molecule that can use simple diffusion to pass through the
cell membrane is oxygen (1). An example of a polar molecule that
would require the use of a channel protein through facilitated
diffusion to pass through the cell membrane is water (1).
Slide 23
LO 1.31 The student is able to evaluate the accuracy and
legitimacy of data to answer scientific questions about the origin
of life on Earth. SP 4.4 The student can evaluate sources of data
to answer a particular scientific question. Explanation: When
scientist consider the conditions that led to the organic compounds
that evolved to the different facets of life that we know today,
there are many experiments that scientist have done to simulate the
conditions that were in early earth se see if they can create
organic compounds.One hypothesis came in the 1920s from Oparin and
Haldane thinking that earths early atmosphere had been a reducing
atmosphere (electron-adding) which organic compounds could have
formed with lightning. The early oceans had a solution of
molecules(Primitive Soup). Then in 1953 and experiment was done
with Miller and Urey to test the Oparin-Haldane hypothesis in which
they set up a closed system which had a flask of warmed water (to
represent the warm sea).This then became water vapor and met
another flask(the reducing atmosphere) which had hydrogen, methane
and ammonia which were abundant in early earth. Then sparks were
put into the flask(lightning). When this simulation was repeated a
lot they found basic organic compound in the water such as amino
acids. It was later seen that only very small pockets had this
reducing atmosphere. They think that it was more likely produced in
hydrothermal vent deep in the ocean. These are the two theories
that scientist believe how life was created. M.C. Question Free
response question a. Considering the Oparin-Haldane hypothesis what
experiment was run that supported this hypothesis? b.Explain what
these experiment proved? c. What type of early compounds were made
out of this experiment? d. What 3 steps are needed to go from an
early organic compound to a complex cell. A lipids B living cells C
Phenylalanine D Pyrimindines E ATP(with Phosphate) In Miller and
Ureys experiment which of the following products was NOT
formed.
Slide 24
Answer key-LO 1.31 In Miller and Ureys experiment which of the
following products was NOT formed A lipids B living cells C
Phenylalanine D Pyrimindines E ATP(with Phosphate) a. Considering
the Oparin-Haldane hypothesis what experiment was run that
supported this hypothesis? b.Explain what these experiment proved?
c. What type of early compounds were made out of this experiment?
d. What 3 steps are needed to go from an early organic compound to
a complex cell. A. The experiment that was used to prove the
Oparin-Haldane hypothesis was the experiment that was done by
Miller and Urey. Which was done in a closed flask using water
vapor, electrodes, and hydrogen, methane and ammonia. B. This
experiment proved that some of the basic building blocks of life,
like amino acids would have been made in the early earth reducing
atmosphere. C. In the Miller and Ureys experiment many different
products were made. When this simulation was repeated a lot they
found that all 20 amino acids were formed, several sugars, lipids
were made, Purines and Pyrimindines, ATP ( after phosphate is
added) and every single monomer was made. D. The three steps that
are needed to go from an early compound to a complex cell. The
first step is a lipid bilayer of a plasma membrane need to form
this can form from lipids in water. The next step is the need for
genetic information(DNA) this information is important because it
includes the instructions to replicate themselves. They third step
is the inclusion of organelles. This could have happened through
serial endosymbiosis. This is where a Ancestral prokaryote which
had a plasma membrane and DNA (step 1 and 2) engulfed a small
aerobic heterotrophic prokaryote which was Mitochondrion. Which
became the heterotrophic eukaryote or the same Large prokaryote
engulfed a photosynthetic prokaryote which now has mitochondrion
and plastid, so now this cell is an ancestral photosynthetic
eukaryote. These are now complex cells.
Slide 25
1) LO 4.20 The student is able to explain how the distribution
of ecosystems changes over time by identifying large-scale events
that have resulted in these changes in the past. 2) SP 6.3: The
student can articulate the reasons that scientific explanations and
theories are refined or replaced. 3) Ecological succession is the
observed process of change in the species structure of an
ecological community over time. Meaning as the environment of an
ecosystem begins to change so will the the plants and animals
living in it and this process is known as succession. There are two
main types of Succession. Primary Succession and Secondary Session.
Primary Succession occurs over a long period of time after a
large-scale event in an area where there is little vegetation, poor
soil quality and hard living environment after the event. In other
words Primary Succession is the beginning of that ecosystem and
follows the changes in it over time. Events that could cause
primary succession are Volcanoes and Ice Ages. When Volcanoes erupt
the lava can flow into the ocean and hardens in to new land. This
new strip of land can then be colonized by Pioneer species, slowly
growing over time Intermediate species will take hold until the
final Climax Community emerges. This process is aided by the
weathering and break up of the lava and organic debris through the
air being deposited onto the new land. Ice Ages can also cause
primary succession to occur. As the World gets colder and glacier
begin to form and creep down or up towards the equator the ice cuts
through the soil and rock in its path. As the Ice age ends like the
one 10,000 years ago did the glaciers retreat and cut out large
canyons and rivers, like the Colorado River and Grand Canyon.
Secondary succession is a process started by an event, such as a
forest fire or hurricane, that reduces an already established
ecosystem to a smaller population of species without completely
destroying the ecosystem. In other words secondary succession is
when a healthy ecosystem has a hurricane or forest fire or some
other short term event damage part of the ecosystem and it has to
repair itself. This is known as secondary succession. Scientific
Theories can act much like Ecological Succession. A theory can be
thought of by the world as completely accurate, but then new
information or a new discovery can cause parts of this completely
accurate theory to be wrong, so it is refined or replaced with a
new one. When the Theory is replaced it acts like Primary
Succession and the theory starts from scratch, where as when the
theory is refined it is more like Secondary Succession and has a
new piece of information added to it and is refined. 4) Multiple
Choice Question: Which of the following Events could result in
Primary Succession? a) Forest Fireb) Glacierc) Earthquaked) Flood
5) Free Response Question: a. Explain the differences between
Primary Succession and Secondary Succession b. Give an example of a
large scale event that could cause primary succession to occur, and
explain what would take place following the event to allow for the
development of an ecosystem.
Slide 26
Answer Key 4) Multiple Choice Question: Which of the following
Events could result in Primary Succession? a) Forest Fireb)
Glacierc) Earthquaked) Flood FRQ) a. Primary Succession occurs over
a long period of time after a large-scale event in an area where
there is little vegetation, poor soil quality and hard living
environment after the event. In other words Primary Succession is
the beginning of that ecosystem and follows the changes in it over
time. Events that could cause primary succession are Volcanoes and
Ice Ages. Secondary succession is a process started by an event,
such as a forest fire or hurricane, that reduces an already
established ecosystem to a smaller population of species without
completely destroying the ecosystem. In other words secondary
succession is when a healthy ecosystem has a hurricane or forest
fire or some other short term event damage part of the ecosystem
and it has to repair itself. So the main difference between the two
is Primary succession occurs at the beginning of an ecosystem and
Secondary Succession occurs in an already developed ecosystem. b. A
volcanic eruption could cause primary succession to occur. When the
volcano erupts molten lava flows out of the volcano and onto land
or water and hardens creating a new land mass. This new land mass
over time will have lichen spores carried by the wind land on the
bare rock face. These lichen will release acids that help break
down the bare rock into a base soil layer and as the lichen die
they will release some basic nutrients into this new soil layer.
Airborne spores from mosses and ferns will then land on the new
base soil layer and will begin to grow. These mosses and ferns will
help further break up the soil and make it thicker. As they die
they will release even more nutrients into the soil and water will
now be able to be held by the soil. Pioneer species of plants and
animals will begin to settle on this new developing ecosystem. As
the pioneer species take hold Intermediate species will move in as
well. Once both the Pioneer and Intermediate species develop and
help the ecosystem a few more species will come and the ecosystem
now after many years will be a climax community.
Slide 27
LO 2.11: The student is able to construct models that connect
the movement of molecules across membranes with membrane structure
and function. SP 1.1: The student can create representations and
models of natural or man-made phenomena and systems in the domain
SP 7.1: The student can connect phenomena and models across spatial
and temporal scales SP 7.2: The student can connect concepts in and
across domain(s) to generalize or extrapolate in and/or across
enduring understandings and/or big ideas Explanation: Membranes are
generally made up of phospholipids and embedded proteins. The
phospholipids make up a fluid bilayer that is hydrophilic on the
outside and hydrophobic on the inside. The fluidity is maintained
by cholesterol amongst the lipids. The hydrophobic center allows
for free movement of nonpolar molecules and some small polar
molecules, while it is impermeable to large polar molecules and
ions. Proteins, including channel proteins and carrier proteins,
are imbedded into the membrane amongst the phospholipids, and
provide pathways across the membrane for molecules specific to the
properties of the protein. For instance, aquaporin proteins allow
for rapid movement of water molecules through the membrane because
of the hydrophilic properties of its channel. Others of these
proteins can use ATP to undergo active transport, which moves
molecules through a membrane against the concentration gradient.
Endocytosis and exocytosis can also occur because the phospholipids
are able to create smaller pockets, called vesicles, to hold
molecules inside them for transport into and out of the cell. All
of these structures and functions play a role in the
semi-permeability of a membrane. Multiple Choice: Which of the
following statements concerning movement of molecules is false?
a)Carrier proteins change their shape to transport molecules.
b)Water moves through the phospholipid bilayer. c)The walls of
vesicles are a phospholipid bilayer. d)Permeability of the bilayer
decreases at low temperatures. FRQ-style Question: What do you
expect would occur if a dehydrated cell is placed in an aqueous
environment? What processes would occur, for what reason, and
how?
Slide 28
Answer Key: LO 2.11 Multiple Choice: Which of the following
statements concerning movement of molecules is false? a)Carrier
proteins change their shape to transport molecules. b)Water moves
through the phospholipid bilayer. c)The walls of vesicles are a
phospholipid bilayer. d)Permeability of the bilayer decreases at
low temperatures. FRQ-style Question: What do you expect would
occur if a dehydrated cell is placed in an aqueous environment?
What processes would occur, for what reason, and how? If a
dehydrated cell is placed in an aqueous environment, the process of
osmosis would occur in order to achieve equilibrium on the inside
and the outside of the cell. Water would flow from the water-rich
environment into the water-deficient cell at a faster rate than the
water will flow from the cell to the environment. Water could flow
through both the phospholipid bilayer of the cell at a relatively
slow rate to achieve equilibrium. Because the center of the
phospholipid bilayer is hydrophobic, however, it will resist the
passage of water and slow the flow down. The water could also use
the channel proteins called aquaporins in order to undergo osmosis
much faster. Because the channels of aquaporins have hydrophilic
traits, water is capable of movement through the channels much more
efficiently than through the phospholipid bilayer. A combination of
these methods of osmosis would occur in this situation in order to
achieve equilibrium, at which point water will flow in and out of
the cell at the same rate, using the same methods once again.
Slide 29
LO 3.20: The student is able to explain how the regulation of
gene expression is essential for the processes and structures that
support efficient cell function. SP 6.2: The student can construct
explanations of phenomena based on evidence produced through
scientific practices. Explanation: Within an organism, all somatic
cells contain the same DNA, as they are all descended via mitosis
from the original zygote. Cells found in different parts of an
organism, however, may display drastically different
characteristics. This is due to different models of gene expression
between the cells. Organisms begin to show cell differentiation, or
differences in structures between cells, starting after only a
couple of divisions. Different levels of certain proteins within a
cell affect how that cell expresses its genes, and these
differences can be found as early as the four-cell stage. Promoters
are proteins that bind to sections of DNA to increase transcription
of the nearby gene, while repressors decrease transcription. In
addition to promoters and repressors, intron splicing can remove
certain parts of RNA after transcription to leave the desired
codons. The first instance of differentiation is the determination
of anterior and posterior sections, and as the organism grows and
finds its shape, more specific differentiation occurs. The many
types of tissues in complex organisms each exhibit their own
characteristics as a result of gene regulation. Within a cell,
genetic regulation also allows the cell to synthesize different
proteins based on messages the cell receives from its environment
or other cells. Hereditary causes of gene regulation are passed on
through epigenetic inheritance, which is passing down of genetic
information that is not coded for in the nucleotide sequence. Gene
regulation can also be controlled by environmental factors such as
exposure to sunlight or heat. Regulation of gene expression is
important for complex organisms because of the various tasks that
they must perform. To accomplish these tasks, an equally varied set
of cells is necessary. For example, a human nerve cell is
dramatically different from a muscle cell. At first glance, the two
cells may appear to be from different organisms. Upon closer
examination, however, the two cells contain the same DNA. The
differences in the proteins and structures of the cells are due to
gene regulation and are the reason that both cells can work to
perform different jobs for the survival of the human. Multiple
Choice: Which of the following best exemplifies how the regulation
of gene expression allows cells to adapt to their environments? a)
A certain protein is found primarily on one side of a human zygote.
b) Daniels mother and father both have brown eyes, but Daniels eyes
are blue. c) Bobbys skin cells translate more of a certain protein
after a long day in the sun. d) Sami grew steadily until the age of
eight, then stopped getting taller Free Response: A scientist is
examining cells from a drosophila and notices that some cells have
a high number of proteins used in the synthesis of mitochondria,
while other cells contain many proteins for ion channels and pumps.
i) What are two possible causes of the disparity in the protein
frequencies between the two types of cells? ii) What advantages do
the two types of cells have in terms of life processes? iii) What
two types of body cells are the scientist likely studying?
Slide 30
LO 3.20: The student is able to explain how the regulation of
gene expression is essential for the processes and structures that
support efficient cell function. SP 6.2: The student can construct
explanations of phenomena based on evidence produced through
scientific practices. Answer Key Multiple Choice: Which of the
following best exemplifies how the regulation of gene expression
allows cells to adapt to their environments? a) A certain protein
is found primarily on one side of a human zygote. b) Daniels mother
and father both have brown eyes, but Daniels eyes are blue. c)
Bobbys skin cells translate more of a certain protein after a long
day in the sun. d) Sami grew steadily until the age of eight, then
stopped getting taller Free Response: A scientist is examining
cells from a drosophila and notices that some cells have a high
number of proteins used in the synthesis of mitochondria, while
other cells contain many proteins for ion channels and pumps. i)
What are two possible causes of the disparity in the protein
frequencies between the two types of cells? ii) What advantages do
the two types of cells have over each other in terms of performing
life processes? iii) What two types of body cells are the scientist
likely studying? i)The different protein frequencies in the two
cells are a result of different gene expression. Cytoplasmic
determinants may have promoted the transcription of mitochondrial
proteins in the first cell type while repressing transcription of
proteins used in ion channels and pumps. In the second type, the
opposite may be true. The gene expressions could also have resulted
from the cells environments. Ligands could have been sent to
neighboring cells of a stimulus, eventually telling the nucleus to
produce more proteins for mitochondrial proteins. ii)The first cell
type is ready to synthesize many mitochondria, where cellular
respiration produces ATP. This means it has an advantage in energy
production over the second cell type. The second type will build
many ion channels and pumps. These will allow it to alter the
concentration of certain ions within its cytoplasm and outside of
the cell, which will help with intercellular communication. iii)The
first cell type is most likely a muscle cell. Muscle cells do much
of the physical work in an organism, so they need a higher amount
of ATP than other cells to power this work. The second cell type is
probably a nerve cell. Nerve cells have to communicate effectively
with each other, and they use differing ion concentrations to
achieve this communication. Diagram source: Howard, Gadi. "Shedding
Light on Blindness." The Future Of Things Science and Technology of
Tomorrow. N.p., 4 Sept. 2007. Web. 01 May 2014..
Slide 31
LO 2.1 The student is able to explain how biological systems
use free energy based on empirical data that all organisms require
constant energy input to maintain organization, to grow and to
reproduce. SP 6.2 The student can construct explanations of
phenomena based on evidence produced through scientific practices.
Explanation: Free energy for organisms is provided by the molecule
ATP, or adenosine triphosphate. ATP has three phosphorus molecules
connected by phosphate bonds. When the bond between two of the
three phosphate molecules is broken by hydrolysis, which is the
splitting of something, the organism is left with adenosine
diphosphate (containing two phosphorus molecules), a free
phosphorus molecule, and free energy that has been released by the
breaking of the bond between the phosphorus molecules. A negative
change in free energy indicates an increase in free energy. Free
energy is also involved in the regulation of an organisms body
temperature. Endotherms use energy they have produced to regulate
their body temperature. Ectotherms use external energy to regulate
their body temperature. Also, keep in mind that there is a
relationship between the metabolic rate of an organism and their
size. A smaller organism will have a higher metabolic rate, or use
energy quicker. In addition to the amounts of free energy needed
for the organism to maintain homeostasis and grow, they need even
more energy to regulate their reproductive cycles and produce
viable offspring. If an organism does not have a sufficient amount
of free energy to regulate their essential functions, they will
eventually not be able to perform these functions anymore and will
die. ATP provides energy for the three types of cellular work:
mechanical, transport, and chemical. In the instance of mechanical
work, it helps to perform tasks such as moving motor proteins by
transferring a phosphate group to the motor protein. Motor proteins
help move organelles and proteins inside a cell, which lets the
cell continue to function and maintain homeostasis. In transport
cellular work, the best known example is active transport. This is
when solutes move against the cells concentration gradient, but
require some sort of force to do it. ATP provides a phosphate
group, which phosphorylates the carrier protein imbedded in the
cell membrane. Phosphorylation of this protein changes the
conformation of the cell, which basically means it makes the
protein pump against the concentration gradient. When the phosphate
group detaches from the carrier protein, it goes back to its
original conformation. Plants employ active transport when they
absorb salts that are diluted in the soil by moving the salt
against the concentration gradient. Since organisms need free
energy to maintain their essential functions, they use a source of
ATP to phosphorylate other molecules and proteins in order to do
cellular work. This cellular work results in maintenance of
homeostasis in the organism. Multiple Choice: Which of the
following is NOT true of ATP being used to do cell work? a.It
phosphorylates a carrier protein to pump molecules through a plasma
membrane from a high solute concentration to a low solute
concentration. b.Once ATP is broken into ADP and a phosphate group,
it rebonds using excess free energy. c.Plant cells depend on ATP
made from the light reaction cycle to power the Calvin Cycle. d.An
exergonic reaction absorbs free energy and therefore results in a
negative G. Free Response Question: An animal cell cannot produce
any of its own free energy. ATP is being synthesized, but not
utilized. What is the cause of the lack of free energy in the
animal cell? What would happen if the problem was fixed? Draw a
diagram of the product of your solution.
Slide 32
Multiple Choice Answer and Explanation: Correct Answer: D An
exergonic reaction results in excess free energy. An endergonic
reaction is the type of reaction that absorbs free energy. When
there is a release of free energy from a reaction, the change in G,
or G, becomes negative. Free Response Answer and Explanation: In
order for ATP to phosphorylate other molecules, it must first be
hydrolyzed. Assuming the ATP is being produced and is fully
functional, the problem is that the cell is not hydrolyzing the ATP
to split it into ADP and a phosphate group. This most likely means
that the cell does not have any H20 with which to hydrolyze the
ATP. The solution to this problem is to simply provide the animal
cell with an amount of water, enough to suffice for hydrolysis and
other necessary cell functions, but not too much as to burst and
kill the cell. If the amount of water is sufficient, the cell will
finally begin to hydrolyze ATP and phosphorylate the necessary
proteins and molecules as well as producing free energy. This will
regulate cell functions and allow the cell to do work in order to
maintain homeostasis. The cell will begin to grow and reproduce
again, improving the overall health of the organism. This is what
normal ATP hydrolysis looks like. If the problem in the animal cell
was fixed, this is what would continue to happen again. ATP would
hydrolyze into ADP and a phosphate group, releasing free energy in
the process.
Slide 33
LO 3.46 The student is able to describe how the vertebrate
brain integrates information to produce a response. SP 1.2 The
student can describe representations and models of natural or
man-made phenomena and systems in the domain Explanation : The body
will first recieve a sensory input. Sensory neurons will transmit
information from sensory organs. The stimuli can be either external
(light, sound, taste, touch, heat, and smell) or, internal ( blood
pressure, CO2 levels or muscle tension). This sensory input is then
sent up the spinal cord to the central nervous system. Interneurons
analyze and intepret this input by reviewing the past and immediate
details. Sensory neurons then communicate with motor neurons that
produces the motor output. The motor neurons then interact with
effector cells (muscle cells or endocrine cells) to produce a
response to the sensory stimuli. Very simple and automatic
responses are known as reflexes. Multiple Choice Question : What is
the purpose purpose of ganglia ( a cluster of neurons segmentally
arranged) in invertebrates and insects ? A) To allow faster
responses between the sensory organs to the spine B) To connect the
CNS with the rest of the animals body ; makes up the peripheral
nervous system C) Helps the CNS neurons interpret signals D)
Supporting cells essential for structual purposes Learning
Log/FRQ-style Question : Suppose you have a patient whom you are
testing in a routine physical. When you test their knee reflex
there is no response. Explain the processs of how sensory input is
processed and possibilities of why you saw no response from the
stimuli.
Slide 34
Answer Key- LO 3.46 Multiple Choice Question : What is the
purpose purpose of ganglia ( a cluster of neurons segmentally
arranged) in invertebrates and insects ? A) To allow faster
responses between the sensory organs to the spine B) To connect the
CNS with the rest of the animals body ; makes up the peripheral
nervous system C) Helps the CNS neurons interpret signals D)
Supporting cells essential for structual purposes FRQ- Suppose you
have a patient whom you are testing in a routine physical. When you
test their knee reflex there is no response.Explain the processs of
how sensory input is processed and possibilities of why your
patient showed no response from the stimuli. The reflex is
stimulated when tapped on the tendon in the quadriceps muscle.
Sensors pick up a stimuli by the stretch in the quadriceps. Sensory
neurons then send this sensory input to the spinal cord. Sensory
and motor neurons communicate with one another. Motor neurons send
signals to the quadriceps to cause them to contract. Whilst this is
happening sensory neurons are also communicating with interneurons
in the spinal cord. These interneurons will inhibit motor neurons
causing the hamstring to not contract. One reason could be a spinal
injury because the motor and sensory neurons can't communicate the
sensory input to produce the motor output within the spine causing
no reaction to happen.
Slide 35
LO 3.43:The student is able to construct an explanation, based
on scientific theories and models, about how nervous systems detect
external and internal signals, transmit and integrate information,
and produce responses. SP 6.2: The student can construct
explanations of phenomena based on evidence produced through
scientific practices. SP 7.1: The student can connect phenomena and
models across spatial and temporal scales. Explanation: The nervous
system can be broken down into two parts: the central nervous
system (CNS) which consists only of the nerves protected by bone
(the brain and spinal cord) and the peripheral nervous system (PNS)
which consists of all other nerves throughout the body. Sensory
neurons are responsible for detecting internal conditions like
blood pressure, blood CO 2 levels, and muscle tension as well as
external stimuli such as light, sound, touch, heat, smell, and
taste. The information is then transmitted to the CNS where
interneurons analyze and interpret stimuli. Motor neurons send
signals to effector cells in muscles or endocrine glands which
produce a response. A neuron has two extensions arising from the
cell body. The dendrites are branched extensions that receive
signals from other nerves cells while the axon is a much longer
extension that sends signals away from the cell body. The axon is
covered by sections of myelin sheath that are separated by a small
gaps called nodes of Ranvier. The myelin sheath allows for signals
to jump from section to section of the axon for much faster travel.
Once the signal is transmitted from the axon hillock to the
terminal branches of the axon (signal only travels in one
direction!), a neurotransmitter is released across the synapse to
the dendrites of another neuron. The signal is converted from
chemical (when received by dendrites) to electrical when traveling
to cell body and through axon and back to chemical as the
neurotransmitter is released across the synapse. M.C Question: How
would nerve impulse transmission be affected if the myelin sheath
on the axon were to deteriorate? A.) The speed of transmission
would stay the same since the impulse travels down the axon on the
inside of the myelin sheath B.) The speed of the impulse would
decrease drastically and would result in symptoms similar to
multiple sclerosis C.) The all or none response would cause the
neuron not to fire at all. D.) The speed of the impulse would
increase since the myelin sheath can no longer slow it down. Free
Response Question: You are fishing for Asian Carp at Lake Michigan
doing your job to reduce the number of invasive species in the
environment. The carp did not look favorably upon your actions and
decided to attack you by flying out of the water and clutching onto
your arm with its mouth. Describe the process behind how you were
able to react to this odd situation.
Slide 36
Answer Key- LO 3.43 M.C Question: How would nerve impulse
transmission be affected if the myelin sheath on the axon were to
deteriorate? A.) The speed of transmission would stay the same
since the impulse travels down the axon on the inside of the myelin
sheath B.) The speed of the impulse would decrease drastically and
would result in symptoms similar to multiple sclerosis C.) The all
or none response would cause the neuron not to fire at all. D.) The
speed of the impulse would increase since the myelin sheath can no
longer slow it down. Free Response Question: You are fishing for
Asian Carp at Lake Michigan doing your job to reduce the number of
invasive species in the environment. The carp did not look
favorably upon your actions and decided to attack you by flying out
of the water and clutching onto your arm with its mouth. Describe
the process behind how you were able to react to this odd
situation. As the carp latched onto my arm, the sensory neurons in
my arm detected the stimuli. The neuron became depolarized at the
axon hillock and a nerve impulse was sent down the axon. The myelin
sheath helped increase the speed with which the signal traveled
down the axon to the terminal branches. The impulse triggered a
chemical signal, or neurotransmitter, to be released across the
synapse to the dendrites of the next neuron. The neurotransmitter
bonded to the receptors on the dendrite and the signal changed from
chemical back into an electrical impulse. The signal was passed
from neuron to neuron in the peripheral nervous system until it
entered the central nervous system and traveled up the spinal cord
to the motor cortex of the brain. Then, my brain interpreted this
stimuli and sent a signal to my arm via depolarization of motor
neurons, much like how my arm sent the signal to the brain. Within
a few seconds of detecting the stimuli, I was able to shake my arm
repeatedly in hopes of getting the stubborn carp to surrender and
release itself from my arm.
Slide 37
LO:2.2 The student is able to justify a scientific claim that
free energy is required for living systems to maintain
organization, to grow or reproduce, but that multiple strategies
exist in different living system. SP:6.1: the student can justify
claims with evidence Explanation: Life requires a constant input of
free energy or else the organism will die. Organisms use free
energy to maintain organization, such as thermoregulation to
regulate body temperature and metabolism. Thermoregulation is the
process in which animals maintain an internal temperature within a
tolerable range. Endothermic animals such as mammals use thermal
energy generated by metabolism to maintain homeostatic body
temperatures, while ectothermic animals like fish and reptiles gain
heat from external thermal energy such as the sun. Reproduction
requires free energy, which causes different reproductive
strategies that is a response to the energy availability. For
example, if female humans as well as other mammals are not taking
in enough food females will not ovulate and are unable to reproduce
due to the lack of energy. Free energy is required to grow and
survive. Excess acquired free energy (you eat more than you burn)
will result in energy storage and growth. Insufficient acquired
free energy or not eating enough will result in mass loss. When
your body doesnt have enough free energy your cells will be starved
and take energy from apoptosis of crucial cells like your muscles.
M.C. Question: Which process does not generate free energy ? A)
Oxidative phosphorylation B) An exergonic reaction C) ATP molecules
bonds are broken by hydrolysis D) An endergonic reaction Learning
Log/Frq-Style Question: All living systems require free energy.
Give 2 examples of how changes in free energy availability can
result In a disruption of an ecosystem.
Slide 38
ANSWER KEY-LO 2.2 Which process does not generate free energy
that can be used to do work? A) Oxidative phosphorylation B) An
exergonic reaction C) ATP molecules bonds are broken by hydrolysis
D) An endergonic reaction All living systems require free energy.
Give 2 examples of how changes in free energy availability can
result In a disruption of an ecosystem. Changes in producer levels
can affect the number and sizes of other trophic levels. If the
amount of producers decreases due to drought this will cause a
decrease of free energy to all the trophic levels above it. Only
about 10% of the energy is passed to the next trophic level due to
energy lost as heat. Energy flows through the ecosystem in the form
of carbon- carbon bonds and as the bonds are broken the carbon
combines with oxygen to form CO2 and energy is released. So if
there is a disruption in producers that causes many producers to
die there is less energy for the primary consumers and the energy
decreases even more as the energy flows up the pyramid. The change
in energy resources such as the sun can affect the number and size
of the trophic levels. Such factors are light intensity, daily
duration, and seasonal changes. Photosynthetic organisms capture
free energy from the sunlight. If there is a lack of sunlight it
directly affects producers and can cause dramatic effects on plant
growth and deprive plants of nutrients which can lead to death. If
there are less producers there will less primary, secondary and
tertiary consumers within the ecosystem since less food and energy
will be available to the higher trophic levels.
Slide 39
LO 3.39 The student is able to construct an explanation of how
certain drugs affect signal reception and, consequently, signal
transduction pathways. SP 6.2 The student can construct
explanations of phenomena based on evidence produced through
scientific practices. Explanation: In order to know how the drugs
affect signal reception and transduction, we must know the
chemicals that can be replaced by drugs. For example, anti
depressants inhibit reuptake and block serotonin from triggering
signals in the brain. This inhibits the entire signal transduction
pathway by not allowing the chemical to receive the signal. The
evidence for these types of studies are produced through scientific
practices. Many years of research and development have gone into
producing drugs that will effectively do what they are intended to
do. In order to be successful on this learning objective, we must
be able to take the evidence that is presented to us and interpret
it correctly to make a good explanation of the phenomena of drugs
affecting signal reception and signal transduction pathways.
Multiple Choice Practice Serotonin levels are one of the main
components of which type of drugs? A.Anti Anxiety B.Anti
Depressants C.Anti Psychotic D.Allergy E.ADHD FRQ Example Explain
what occurs when a drug blocks the reception site of the
neurotransmitter. Give a description as well as examples of what
occurs and what does not occur within the neuron when this
occurs.
Slide 40
Multiple Choice Practice Serotonin levels are one of the main
components of which type of drugs? A.Anti Anxiety B.Anti
Depressants C.Anti Psychotic D.Allergy E.ADHD FRQ Answer When a
drug targets a neurotransmitter receptor on a neuron, it binds to
the receptor and inhibits the neurotransmitter from triggering a
response from the neuron. A great analogy is that of a lock and
key. The lock is the receptor site and the key is the
neurotransmitter. When the key turns the lock, the lock opens so
when the neurotransmitter binds to the receptor site, the response
is triggered. The drug would act as an incorrect key in a lock. It
would enter the key hole but it would not be able to turn the lock
and unlock the lock. So the drug would fit onto the receptor site
but not trigger the neuron to fire. This inhibits the signal
transduction pathway. Normally when a neuron is told to fire the
response travels down the neuron through the axon to the axon
terminal and into the synapse, where the neurotransmitters bind to
the dendrites of the next neuron and cause it to fire and give a
response. When the receptor site is inhibited, this process does
not occur and therefore the signal is not carried on and the
response that is desired is not achieved. An example of this is
when anti anxiety drugs are taken. The drugs target the receptors
for neurons that help facilitate a stress response. This means that
the stress response is not achieved as often as it normally would
be. This is very helpful to someone with anxiety because it limits
the st