Web viewIf a DNA stand of average size (140 million nucleotides long) ... that then supercoil to...
-
Upload
trinhthuan -
Category
Documents
-
view
214 -
download
0
Transcript of Web viewIf a DNA stand of average size (140 million nucleotides long) ... that then supercoil to...
-DNA to Protein Notes-
Notes #1 – DNA Structure
Pre-Assessment Make a list of thing you know about DNA.
Is Genetic Material DNA or Protein??? - Fredrick Griffith – 1928
Conclusions and Questions After Griffith’s discoveries, along with the input of others, scientists were
confident that __________ was the genetic material. However many questions remained:
o How do _______________________ come together to form a DNA molecule?o How does DNA __________________________ information with the other
parts of the cell?
Nucleotides Nucleotides are _________________________ that make up the polymer, nucleic
acids (macromolecule). Subunits of a nucleotide:
o _____-carbon sugar (deoxyribose or ribose)o ______________________ groupo ______________________ base
Adenine (A) Thymine (T) – ________ only Guanine (G) Cytosine (C) Uracil (U) – _________ only
Nitrogenous Base Pairing Erwin ____________________ analyzed the amount of adenine, guanine, thymine
and cytosine in the DNA of various species. He noticed there is nearly the same _________________ of A and T and G and C. From this he developed Chargaff’s rule:
o A = _____o G = _____
The Discovery of DNA Structure Wilkins (chemist) and Franklin (physicist) used a technique called X-ray
______________________ to get the first picture of DNA. Their famous photo indicated that DNA was a ___________________ helix, formed
by two strands of nucleotides ________________ around each other.
Watson and Crick These two scientists used Franklin’s photo and data to build a _____________ of
the double helix DNA. o Two outside strands consist of alternating _____________________ and a
______________________ groupo C and G bases pair to each other by ___________ hydrogen bondso T and A bases pair to each other by __________ hydrogen bonds
DNA Structure The structure of the DNA molecule is often compared to a _____________ Deoxyribose and the phosphate group alternate, forming the __________________
rails. The pairs of nitrogenous bases (A-T and G-C – known as complementary
pairs) form the ____________ or rungs of the ladder.
Orientation of DNA DNA is _______________ stranded There is a unique _______________________ and ______________________ of each strand. The end of the strand that ends with the ____________________ group is called the
5’ (five prime) end. The end of the strand that ends with _________________________ is called the 3’
(three prime) end.
Notes #2 – Chromosome Structure
Prokaryotes vs. Eukaryotes Prokaryotic cells, like bacteria, do not have a _______________. Therefore, their
DNA floats around in the ______________________. Prokaryotic cells contain one chromosome that is ___________________ in shape. Eukaryotic cells, like plant and animal cells, have a _______________. All of the
____________ of the cell is contained in the nucleus. Eukaryotic cells contain many __________________ chromosomes (46 in humans). The __________________ of a human chromosomes ranges from 51 million to 245
million base pairs (A – T and G – C) If a DNA stand of average size (140 million nucleotides long) were laid out in
a straight line, it would be about _________ centimeters long!
How does DNA fit into the cell? Answer: You ______________________ it! In order for DNA to fit into the microscopic nucleus of a eukaryotic cell, it is
tightly coiled around a group of beadlike proteins called __________________. Then they form into larger balls called _____________________________. The nucleosomes then group together into chromatin fibers, that then
supercoil to make up the structure that we call a ________________________.
Graphic OrganizerChromosome
Notes #3 – Replication of DNA
When does the cell replicate its DNA?
Semiconservative Replication When DNA is copied during the S phase (interphase) of the cell cycle it occurs
by _____________________________ ____________________________. This is a method by which the ___________________ strands of DNA separate,
serve as templates, and produce DNA molecules that have one strand of parental DNA and one strand of __________ DNA.
This replication process can be broken down into 3 steps:1. Unwinding2. _____________ ___________________3. Joining
Notes #4 – Transcription
Central Dogma of Biology DNA is the genetic material of a cell, but how does it act as a code for the
_______________________ of materials within the cell? Through experimentation and research, it was discovered that DNA coded
for ____________________ (polypeptides). Proteins function as structural _____________ blocks for the cell and as enzymes. Biologists and Geneticists now accept the ________________________________________,
or how genes are expressed, by this statement:
DNA ________ ____________
RNA RNA is a nucleic acid like __________, but differs in
o The ________________ it contains (ribose instead of deoxyribose)o The nitrogenous base _______________ replaces thymineo RNA is ___________________ stranded instead of double stranded
There are 3 major type of RNA found in living cells:o Messenger RNA (____________)o Ribosomal RNA (___________)o Transfer RNA (____________)
Type of RNA Description Location
Transcription _________________________ is the first step of the central dogma of biology. It
involves the synthesis of mRNA from DNA. The DNA code is transferred to mRNA in the nucleus by an enzyme called
_______________________________________. RNA polymerase II can _________________ and unzip a DNA molecule and write a
complementary RNA strand using a single DNA strand as a template.o RNA polymerase II reads in the ______’ ______’ direction.
The DNA used to make the mRNA is called the ____________________ strand. As the ___________________________ mRNA strand is made, G is matched with C,
but A is matched with U. Once transcription is complete, RNA polymerase II releases the DNA
molecule and the new __________ moves out of the nucleus through nuclear pores.
RNA Processing When scientists compared the template strand of DNA with newly formed
mRNA, they found that the newly formed mRNA was the same ___________ as the DNA strand.
However, before translation occurs, the mRNA is __________________ drastically. They later discovered that some of the original mRNA (known as pre-mRNA)
doesn’t code for anything, so it is ________ out of the strand. These sequences that are intervening with the code and are cut out are called
___________________. The coding sequences that remain in the final mRNA are called _____________.
This is what gets translated into proteins.
Notes #5 – Translation
The Code When biologists first studied DNA, they realized the only way that it varied
between organisms was in its sequence of ____________________. They new that there were _____ amino acids, so there had to be at least 20
different codes. They now know that the code for a single amino acid includes _____ bases. There are 64 possible triplet codes in mRNA; they are called __________________.
Translation Once mRNA is synthesized in the nucleus it moves to the ________________
where it finds a ribosome. When the mRNA arrives, the 5’ end connects it to the _____________________. The ribosome will read the nitrogenous base code of the mRNA and translate
it into a protein in a process called _____________________________.
tRNA and Translation In translation, ___________ molecules act as the interpreters of the mRNA codon
sequence. tRNA have a clover-like shape and have ________________ ____________ attached to
one end by an enzyme. The other end of the molecule, there is a 3-base coding sequence called the
______________________. Each anticodon is complementary to a codon on the ____________. It is important to note, that the mRNA is read ____’ to ____’ (see chart).
The Role of the Ribosome The ribosome is made of ________ subunits, which come together and attach to
mRNA in the cytoplasm. Once the ribosome is associated with the mRNA, a tRNA molecule carrying
the amino acid _________________ (Met) and the anticodon UAC will be the first to bond.
Methionine is always the first amino acid in a protein (polypeptide) because the codon, AUG is the __________ codon.
The start codon ___________________ translation. The structure of the ribosome has ______ grooves, seen below. They are known as the ____, ____, and ____ site. These grooves are what accept the ________ molecules as they bond to the
mRNA. The first tRNA carrying Met moves in and bonds to the _____ site. Next, another tRNA moves in and lands in the _____ site. The amino acid from
the P site is ______________ to the A site. This is __________’s role: Acting as an enzyme to pass the amino acids from the
P site to the A site. Once the amino acid(s) have been passed from the tRNA of the P site to the A
site, the mRNA moves down one codon. The tRNA that was in the P site is now shifted to the ____ site, where it ________. The tRNA that was in the A site is now shifted to the ____ site and contains the
amino acid chain. This leaves the ____ site open for the process to start over again for the next
codon. This will go on until the strand of mRNA ends. Then the mRNA and the
amino acid chain are ___________________. The amino acid chain will then fold into a _________________.