TEK 6F EOC Review

Focus:Concept

ProcedureApplication

An Explanation of Punnett Squares Monohybrid & Dihybrid

Crosses, Karyotypes & Pedigrees

GENETICS

• The scientific study of heredity

• In order to understand genetics you have to know that genes are being shared during___________________

Fertilization

During sexual reproduction male ( ) & female ( ) ♂ ♀

___________cells join to produce a NEW cell, which develops into an ___________

Gregor ___________

• “The _______ of Genetics”• An Austrian Monk who was in

charge of the garden @ the monastery

• He played around with ______ plants, & from his findings he recorded the beginnings of the study of Genetics

True Breeding

• Organisms that are allowed to self pollinate & they produce offspring that are identical to themselves

• True bred pea plants were the __________

• in Mendel’s experiments

Hybrids

Offspring of crosses b/twparents w/ different traits

Circle the Hybrid(which one is it?BB or Bb or bb

Traits

A specific characteristic that varies from 1 individual to another

Generations of Crosses

P Generation“Parental Generation”The original pair to fertilize offspring

F1 Generation“1st Filial Generation”Filius & Filial are the Latin words for “_____” or“_______________”

Genes

• Chemical factors that are passed down fr/ 1 generation to the next

• They determine the ______!

Alleles

• They are different forms of the genes

• Some Alleles are Dominant & others are ______________

• Dominant Alleles are denoted by Capital letters (e.g.; T = Tall) & recessive alleles are lower case letters (e.g., t = short)

Principle of Dominance

States that:

1. An organism w/ a dominant allele for a particular form of a trait will _____________express that allele

2. An organism w/ a recessive allele will ____________ express that trait if there is NO form of the dominant allele present

Punnett Squares

• They show the different gene combos that might occur fr/ a genetic cross b/tw a male and a female.

• They can be used to ___________ & ____________the genetic variations

Homozygous vs. Heterozygous

HomozygousThe organism hasboth of the samealleles for the trait

(e.g.; BB = brown or bb = blue)

Heterozygousthe organism has 2different alleles forthe same trait

(e.g.; Bb = brown)

Genotype vs. Phenotype

GenotypeWhat the genesRead!

Bb(e.g. exactly what is writtenin the punnett sq )

PhenotypeWhat it looks like

(e.g.; Brown eyes)

Beyond Dominance & Recessiveness

There are important exceptions to the Rule:

________ all genes show basic dominant and recessive alleles.

BBbb

where the heterozygous phenotype is somewhere ___ __________the two homozygous phenotypes.

Incomplete Dominance

CodominanceWhere __________alleles contribute to the phenotype.

For example: in chickens, the allele for black feathers is codominant with the allele for white feathers. Heterozygous chickens have a color described as “erminette,” speckled with black and white feathers.

“ Anyone seen my contact lenses?

Multiple Alleles

When ________ ____ ______possible alleles exist in a population.

Ex: coat color in animals & Blood Type in Humans

A man who has AB blood marries a woman who is heterozygous for B blood. What are the possibilities of blood types their children can be born with?

Genotype =

Phenotype =

Polygenic Traits

Where _____ ______( more than just 2)control the expressions of traits.

Examples: skin color & hair color

2 Factor Punnett Square Cross

Where Mendel took 2 Factors and crossed them in the same punnett square to see the different combos

When there is a Heterozygous Di-hybrid cross the Phenotypic Ratio = 9:3:3:1

Types of Sex C’somes

• X c’some – found in women and men, much larger in size

• Y c’some – found ONLY in men, much smaller

Women vs. MenWomen:• Chromosome # is written 46, XX

(for “normal” women)

• ONLY have X c’somes therefore they can only donate an X c’comes to their children

Men:• Chromosome # is written 46, XY

(for “normal” males)

• Because men have the presence of both sex c’somes they are the ones that DETERMINE the sex of the child.

Karyotype

• A photograph which shows all of chromosomes that are inherited from the parents.

• Normal # of chromosomes is 46 in body cells and 23 in gametes (sex cells)

Chromosome (c’some) #s

Out of the 46 c’somes:• 44 are autosomes (body

c’somes) – pairs numbered 1 thru 22

• 2 are sex chromosomes (the 23rd pair ONLY)

Pedigrees

= females• = males• = female that

expresses the trait• = male that

expresses the trait• = marriage• = offspring

Sex linked traits“X-Linked Traits”

Genes that are usually found on the X-chromosome.

Few are on the Y-chromosome

*If the mother is a carrier of or is affected by a sex linked trait her son’s are almost always affected… B/c Boy’s only receive one X-chromosome, they express EVERYTHING that’s on it!

Colorblind

Sex linked trait found on the X-c’some where the patient has lost the ability to distinguish certain colors

Colorblindness

Hemophilia

A sex linked disorder found on the X-c’some that does not code for the protein necessary to clot blood

Hemophilia

6F

Conceptual Problems

1. If an organism has the genotype RrSsTtUu, what proportion of its gametes will be RSTU?

A. ½B. ¼C. 1/8D. 1/16

2. In humans, freckles are encoded by a dominant allele. An individual woman is heterozygous for freckles. According to the law of segregation, which of the following would apply to a child of this woman?

A. The child must inherit the dominant allele for freckles.B. The child must inherit the recessive allele for freckles.C. The child has an equal chance of inheriting the dominant

allele or the recessive allele for freckles from her mother.D. The child has a greater chance of inheriting the dominant

allele than the recessive allele for freckles from her mother.

3. The illustration below shows two adult rabbits and their offspring. In rabbits, the allele for spots (R) is dominant to the allele for solid color (r). What is the most likely genotype of the parent rabbits in the illustration?

A. rrrrB.RrrrC. RrRrD. RRrr

4. In pea plants, the allele for purple flowers (P) is dominant to the allele for white flowers (p). A plant that is heterozygous for purple flowers is crossed with a plant with white flowers. What percentage of the offspring plants are expected to have purple flowers?

A. 25%B. 50%C. 75%D. 100%

5. In a certain variety of chicken, some offspring have a feather pattern that is black-and-white checkered. Chickens with this checkered feather pattern result from the cross of a black chicken with a white chicken. Which of the following types of inheritance is most likely responsible for the checkered feather pattern?

A. codominantB. dominantC. polygenicD. sex-linked

6. In sheep, the allele for white wool (W) is dominant, and the allele for black wool (w) is recessive. A farmer has mated two Suffolk sheep for a few years. These matings have resulted in six offspring, four with white wool and two with black wool. One parent has white wool and the other has black wool. Which of the following could be the genotypes of the parent sheep?

A. WW and WwB. WW and wwC. Ww and WwD.Ww and ww

7. Female cattle that have white coats are crossed with male cattle that have red coats. Both male and female offspring have roan coats, which are coats with both red hairs and white hairs. Which of the following best describes the genetics of coat color in the cattle?

A. The red and white alleles are sex-linked.B. The red and white alleles are codominant.C. The red allele is recessive to the white allele.D. The red allele is dominant to the white allele.

8. Leaves from two white clover plants, each with a different pattern, are shown below. The leaf patterns are genetically determined by alleles of a single gene. Plant 1 is homozygous for the chevron allele. Plant 2 is homozygous for the oval allele. The chevron and oval alleles are codominant. If plant 1 and plant 2 are crossed, the codominance of the alleles will most likely result in which of the following leaf patterns on the offspring plants?

9. If Mendel were given a mommy black mouse & a daddy white mouse & asked what their offspring would look like, he would've said that a certain percent would be black & the others would be white. He would never have even considered that a white mouse & a black mouse could produce a GREY mouse! What accounts for a mouse offspring with all grey hair from parents that is black and a parent that is white. _________________________

10. Give the phenotypic ratio of the Dihybrid

cross:

6F

Procedure Problems

11. Hawaiian happy face spiders from the island of Maui can have different markings, as shown below. A single gene determines the markings on the spiders. A plain spider is crossed with a patterned spider. The patterned spider is homozygous. The pattern allele is dominant to the plain allele. What percentage of the offspring from this cross are expected to be patterned instead of plain?

A. 0% B. 25% C. 50%D. 100%

12. A partial Punnett square is shown below. Which of the following statements describes the parental genotypes that would result in this Punnett square?

A. Both parents are heterozygous.B. Both parents are homozygous

dominant.C. One parent is homozygous

recessive and the other parent is heterozygous.

D. One parent is homozygous dominant and the other parent is heterozygous.

Genotype =

Phenotype =

Genotype =

Phenotype =

Genotype =

Phenotype =

16. Solve:

6F

Application Activities

6F: 4 Pictures – 1 Word

Teachers show the next 6 slides to your students… They will have to apply their

knowledge of the subject matter to solve

STAAR Review

© 2013

STAAR Review

Created by Ms. Johnson’s Eagle’s Nest Biology Student:

Jorge Camarillo

© 2013

STAAR Review

Created by Ms. Johnson’s Eagle’s Nest Biology Student:

Jorge Camarillo

© 2013

STAAR Review

© 2013

Olsen Twins

STAAR Review

© 2013

STAAR Review

© 2013

6F: Station Map

Print a class set of the following slide for your students to work

TEK #6: The student knows the mechanisms of genetics, including the role of nucleic acids and the principles of Mendelian Genetics. The student is expected to (F) predict possible outcomes of various genetic combinations such as monohybrid and dihybrid crosses and non-Mendelian inheritance; Readiness Standard

“Keep it in the Family”Directions: Part 1 = Write down and correctly label the provided karyotypes below.Part 2 = Read the problem below solve the punnett square and shade in the circle(s) and/or square(s) for who expresses the trait.

Freckles are dominant (F) over non-freckles (f). In this pedigree the shaded individuals are freckled. What is the genotype of individual B if they have 50 : 50 chance on having kids with freckles or without freckles?

Complete the punnett square below that corresponds to the individuals in the pedigree who have freckles, and give the parents & children's genotypes.

A B

C D E

F f

STAAR Review

Created by Ms. Johnson’s 5th period Biology Students:

Gloria Arana & Salvador Lopez

© 2012

STAAR Review

Created by Ms. Johnson’s 5th period Biology Students:

Calvin Bass & Jennifer Lopez

© 2012

WORD BANK for KARYOTYPES:

Male, Female, Down Syndrome/Trisomy 21,

Kleinfelters Syndrome, Turners Syndrome

6F: Activity

Have the students pull out a sheet of paper & play the youtube clips for the

students to draw out & solve the man’s family pedigee.

I’m My Own Grandpa

http://youtu.be/rXU-ZdmzNmo

http://youtu.be/W7x1ETPkZsk

http://youtu.be/zeIsxXDyjlc

Now many many years ago when I was twenty-three I was married to a widow who was pretty as can be. This widow had a grown-up daughter who had hair of red. My father fell in love with her and soon they too were wed. Oh, I'm my own grandpa I'm my own grandpa It sounds funny I know But it really is so Oh, I'm my own grandpa. This made my dad my son-in-law and changed my very life. My daughter was my mother, 'cause she was my father's wife. To complicate the matter even though it brought me joy, I soon became the father of a bouncing baby boy. My little baby then became a brother-in-law to Dad, And so became my uncle though it was very sad. For if he was my uncle then that also made him brother Of the widow's grown-up daughter who of course was my step-mother. Father's wife then had a son who kept him on the run, And he became my grandchild for he was my daughter's son. My wife is now my mother's mother and it makes me blue, Because although she is my wife she's my grandmother, too. Now if my wife is my grandmother then I'm her grandchild, And every time I think of it it nearly drives me wild, For now I have become the strangest case I ever saw. As husband of my grandmother, I am my own grandpa.

Copyright Moe Jaffe and Dwight Latham, 1947