Biology assignment 2

Name:___________________

Genetics and Society

Ch. 3 Genetics Practice problems – 15 points

1. For each genotype below, indicate whether it is heterozygous (He) or homozygous (Ho)

AA Homozygous Aa Heterozygous ff homozygous Ff Heterozygous

2. For each of the genotypes below, determine what phenotypes would be possible

Purple (P) flowers are dominant to white (p) flowers

PP___________________

Pp___________________

pp___________________

Brown (B) eyes are dominant to blue (b) eyes

BB___________________

Bb___________________

bb ___________________

3. For each phenotype below, list the genotypes

Tall (T) plants are dominant to short (t)

____ Tall

____ Tall

____ short

Smooth (S) seeds are dominant to wrinkled seeds (s)

____ smooth

____ smooth

____ wrinkled

4. Set up the Punnett Squares and calculate the percentages for each of the crosses listed below The first one has been done for you. *I have created text boxes to make it easier to fill in

Yellow seeds (Y) are dominant to green seeds (y)

Y Y

A. YY x yy

Yy

Yy

Yy

Yy

y

y

What percentage of the offspring will be

Yellow? 100%

What percentage of the offspring will be

Green? 0%

What percentage of the offspring will be

Homozygous? 0%

What percentage of the offspring will be

Heterozygous? 100%

B. Yy x yy (2 pts)

What percentage of the offspring will be

Yellow? ____

What percentage of the offspring will be

Green? _____

What percentage of the offspring will be

Homozygous? ____

What percentage of the offspring will be

Heterozygous? ____

C. YY x Yy (2 pts)

What percentage of the offspring will be

Yellow? ____

What percentage of the offspring will be

Green? _____

What percentage of the offspring will be

Homozygous? ____

What percentage of the offspring will be

Heterozygous? ____

Using the information given, solve the following genetics problems.

5. Albinism is a recessive condition (a). A normally pigmented woman and an albino man have 4 non albino children and one albino child. (3 pts)

A. What is the genotype of the mother? ____

B. What is the genotype of the albino child? ____

C. What is the genotype of the non albino children? ____

6. Mr. and Mrs. X discover that they are both heterozygotes (Tt) for the allele for Tay-Sachs disease (a recessive disorder). (2 pts)

A. What percentage of their children are expected to have the disease? ____

B. What percentage of their children are expected to be phenotypically normal? ___

*Use the Punnett square below if necessary

7. Huntington’s disease (H) is an autosomal dominant condition. A man with Huntington’s disease discovers he is heterozygous for the disease allele. His wife does not carry the disease allele. (3 pts)

A. What is the genotype of the man? _______

B. What is the genotype of his wife? ________

C. What percentage of their children are expected to carry the Huntington allele? ______

*Use the Punnett square below if necessary

Genetics and Society

Ch. 3 Single Gene Traits

5 points

In this activity you will be examining eight observable traits. For our purposes, you can assume that each trait is controlled by a single pair of alleles. For each trait described, record your phenotype and possible genotype in Table 1. Use the letter symbols given below for each genotype. Answer questions #1 and #2.

Traits:

1. Tongue rolling – The ability to roll the tongue is dominant (R), while non-rolling is recessive (r).

2. Free ear lobe - A free-hanging earlobe is dominant (E). The attached earlobe is recessive (e)

3. Hand clasping – Clasp your hands together. Notice whether you left or your right thumb is on top. If the left thumb is on top, you have the dominant trait (C), the right on top is recessive (c).

4. Hitchhiker’s thumb – Hold out your hand and make a fist with the thumb extended. Bend the last joint of the thumb back as far as possible. A straight thumb is dominant (S) while a bent thumb is recessive (s).

5. Widow’s peak – A hairline with a distinct point in the middle of the forehead is dominant (W). The straight hairline is recessive (w).

6. Dimpled chin – A cleft in the chin is a dominant trait (D). No cleft in the chin is recessive (d).

7. Curly hair – Curly hair is dominant (P) to straight hair (p). *If you hair is wavy at all, call is curly

8. Short big toe – A big toe that is shorter to the second toe is dominant (T) to a big toe that is longer than the second toe (t).

Table 1: Single gene trait observations

Trait studied	Your phenotype	Your possible genotype(s)
Tongue roller Non Tongue roller
Free ear lobes Attached ear lobes
Hand Clasp (L over R) Hand Clasp (R over L)
Thumb – Straight Thumb – Bent
Widow’s peak Straight Hairline
Dimpled chin No dimple
Curly hair Straight hair
Short big toe Long big toe

1. Why is it that if you have the dominant phenotype, you must record your possible genotype? What information must you have to know you actual genotype?

2. Why is it that if you have the recessive phenotype, you automatically know your genotype?

Ch. 4 and 5 -Codominance and X linked Genetics problems

25 points

Ch. 4 - Codominance Genetics problems:

Example of an ABO blood type inheritance problem:

I have type A blood. My husband has type O blood. What are our genotypes?

Me: IAi or IAIA

My husband: ii (O is recessive so he must have two copies of the recessive allele)

Is there a chance that we could have children with the following blood types?

Type B: no, neither of us has the B allele

Type AB: again, no because neither of us has the B allele

Type A: Yes, if I am homozygous for the A allele (IAIA), then all of my children will be type A; if I am heterozygous (IAi), then 50% of my children will be type A

Type O: Yes, but only if I am heterozygous and give the O allele. My husband can only give the O allele

Use the examples above to answer the following ABO blind type inheritance problems:

1. A woman with type A blood has a child with type O blood. The man she says is the father has type AB blood. Is it possible for this man to be the father? Justify your answer by showing the genotypes of the mother, child, and potential father. (3 pts)

Mother:

Child:

Potential father:

2. In a trial in 1945, a woman accused Charlie Chaplin of fathering her child. The ABO blood types were as follows:

woman- Type A; Chaplin- Type O; Child- Type B

Was it possible for Charlie Chaplin to be the father of the child? Explain your answer. (2 pts)

3. A woman with type O blood marries a man with type B blood. (3 pts)

a. What is the woman’s genotype?

b. What is/are the man’s genotype(s)?

c. What are the potential genotypes of their children?

Ch. 5 – X linked inheritance problems:

Below is an example of an X-linked inheritance problem.

Part A. A boy, whose parents and grandparents had normal vision, is color-blind. What are the genotypes for the boy, his mother and his maternal grandparents? Use XB for the dominant normal condition and Xb for the recessive, color-blind phenotype. Color-blindness is a sex-linked trait.

Boy: XbY – since it is a boy – chromosomes must be an X and a Y; He is colorblind so he must have the color blind allele

Mom: XBXb - Mom must be heterozygous because she has to be the one that gives the Xb to her son

Maternal grandmother: XBXb – must be a heterozygote because she has normal vision but the mom (her daughter) has to get the Xb from one of her parents

Maternal grandfather: XBY – problem says he has normal vision so this must be his genotype

Part B. This mom is married to a man with normal vision. What is his genotype?

His genotype must be XBY because he is a male and he is not color blind.

XB Xb

What percentage of their daughters will be colorblind?

0%

XBXB

XB

Y

XBXb

What percentage of their sons will be colorblind?

50% (it isn’t 25% because you are only looking

at the sons)

What percentage of their daughters will have normal vision?

XbY

XBY

100%

What percentage of their sons will have normal vision?

50% (again, it isn’t 25% because you are only looking

at the sons)

Use the examples above to answer the following X linked inheritance problems:

Problem #1:

1. Hemophilia is an X-linked, recessive condition. Xh is the allele for hemophilia, XH is the normal allele. A normal woman and a normal man have a son with hemophilia. What are the genotypes of each? Use the genotypes of the parents to complete the Punnett Square below. (3 pts)

a. Woman:

b. Man:

c. Son:

2. What percentage of their daughters are

expected to have hemophilia? ____ (1 pt)

3. What percentage of their daughters are

expected to carry the disease allele but not

show the condition? _____ (1 pt)

Problem #2:

1. A woman with red-green colorblindness has a mother with normal vision. Knowing that color-blindness is an X-linked recessive trait (Xb), determine her genotype and that of her parents: (3 pts)

a. Woman:

b. Mother:

c. Father:

2. This same woman marries a man with normal vision. What is his genotype? ___ (1 pt)

3. Complete the Punnett Square below showing the possible genotypes of their children.

4. What percentage of their sons are expected to be red-green colorblind? ____ (1 pt)

5. What percentage of their daughters are expected to be red-green colorblind? ____ (1 pt)

Problem #3

Use the information on Slides 17, 18 and 19 of the Ch. 5 PowerPoint file to answer the questions below.

· My maternal grandfather was color blind and my brother is color blind. Both of my parents have normal vision. I have normal vision. My husband has normal vision. Based on this information, answer the questions below.

1. Is there a chance that my son will be colorblind? Justify your answer. (2 pts)

2. Is there a chance that my daughter will be colorblind? Justify your answer. (2 pts)

3. Is there a chance that my nieces will be colorblind? Justify your answer. (2 pts)

Sex Verification Testing of Athletes

https://media.hhmi.org/biointeractive/click/testing-athletes/index.html

Click on the link above. As you proceed through the interactive, follow the instructions and answer the questions below. Answer the questions in your own words. Any “copy and paste” answer will not receive credit

INTRODUCTION

Select the “Introduction” tab and watch the opening video. After watching the video, scroll down and read the text. Use the information in the video and the text to answer the questions below. As you read, click on the underlined terms to learn more about them. When you have finished, answer questions 1-3 below.

1. Why was Dutee Chand dropped from the Indian national track team in 2014?

2. What was the option given to Chand?

3. In 2015, the governing body for track and field athletics voted to suspend the “testosterone rule.” What is the consequence of this?

4. When did sex verification tests in sports begin and what was the purpose of these tests?

5. Why is thought that a high level of testosterone provides an unfair advantage in women’s athletics?

6. Click on the term “biological sex.” Explain the difference between biological sex and gender.

7. Are sex verification tests of athletes used to determine biological sex or gender? Justify your answer.

HUMAN DEVELOPMENT

Click the “Human Development” tab. As you navigate through this section, use the information to answer the questions below.

8. What is a Barr body?

9. What does the presence of a Barr body indicate?

10. Regarding the SRY gene…..

a. What does SRY stand for?

b. On which chromosome is the SRY gene normally found?

c. What is the function of the SRY gene?

11. If an athlete was being subjected to sex verification tests using presence or absence of Barr bodies and the SRY gene. What would the results need to be in each case in order for the athlete to compete in women’s events?

12. Secondary sex characteristics arise during puberty. What causes these developmental changes?

13. Why do females typically produce less testosterone than males?

14. Genetic variations can result in differences in sex development (DSD). Click on DSD under the Phenotypes section.

a. What is another term used for DSD?

b. How common are DSDs?

Answer the following questions using the table of DSDs.

15. CYP21A2 gene mutations

a. By what mechanism can a mutation in CYP21A2 change testosterone levels?

b. What biological sex is usually assigned at birth in people with a CYP21A2 mutation?

16. SRY gene mutations

a. What is the effect of a nonfunctional SRY gene on the development of primary sex characteristics?

b. Which sex is typically assigned at birth to an individual with a mutation that results in a nonfunctional SRY gene?

17. 45,X (XO)

a. An error during meiosis when homologous chromosome do not separate can result in Turner syndrome. What is this error called? (review your notes from module 1 to answer this question)

b. Can an individual with Turner syndrome have biological children?

18. AR gene mutation

a. What is the normal function of the androgen receptor?

b. Which phenotypes may arise in an individual with a mutation in the AR gene?

c. In humans, the AR gene is located on the X chromosome. If a person who is XY has a complete deletion of the AR gene, do you think giving them testosterone injections during puberty would cause an increase in expression of male secondary sex characteristics compared to not receiving injections? Explain your answer.

19. XXY

a. Which sex is typically assigned at birth to an individual with XXY chromosomes?

b. If a person with Klinefelter’s syndrome wanted to look more like an average male, what medical treatment could help accomplish this?

CASE STUDIES

Click the “Case Studies” tab, read about the two athletes and the history of sex verification tests, and then use the information to answer questions 16-17.

20. Click the "Sprinter" tab.

a. For each of the years, indicate which sex verification test is used and if this athlete would be allowed to compete in women’s events based on the result of that test

1966 –

1968 –

1992 –

2011 –

b. What is a genotype that would explain the sprinter’s phenotype? Explain.

21. Click the "Swimmer" tab.

For each of the years, indicate which sex verification test is used and if this athlete would be allowed to compete in women’s events based on the result of that test

1966 –

1968 –

1992 –

2011 –

Under current regulations, would the swimmer be allowed to compete? Explain.

CONCLUSION

Click the “Conclusion” tab and answer the following questions

22. Use the spectrum of gender identities figure and explain the difference between a cisgender woman and a transgender woman.

23. As of 2015, what is the condition for transgender female athletes to compete in women’s events.

24. Currently, are the conditions based on testosterone for cisgender female athletes to compete in women’s events? If so, what are they?

25. After going through this activity, what are your thoughts on sex verification in athletes?

a. Should athletes be tested for their testosterone levels in order to be able to compete in women’s events? Why or Why not?

b. Should we eliminate the practice of dividing sporting events into male and female categories? Why or Why not?

Humans have either functioning male or female reproductive structures, but not both.  This means they are

Group of answer choices

haploid

diploid

dioecious

monoecious

 

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Question 20.5 pts

Humans without any X chromosomes can still survive.

Group of answer choices

True

False

 

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Question 30.5 pts

Humans can survive if they do not have a Y chromosome.

Group of answer choices

True

False

 

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Question 40.5 pts

The X and Y chromosomes are homologous.

Group of answer choices

True

False

 

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Question 50.5 pts

In humans, females receive their X chromosomes from

Group of answer choices

both their mother and their fateher

just their mother

just their father

either their mother or their father

 

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Question 60.5 pts

Males receive their X chromosome from

Group of answer choices

either their mother or their father

only their father

both their mother and their father

only their mother

 

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Question 70.5 pts

What is the main function of the SRY gene?

Group of answer choices

it produces estrogen in females

it starts the develop of female ovaries

it makes testoterone

it starts the development of testes in males

 

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Question 80.5 pts

Sex determination is temperature dependent in some reptiles.  

Group of answer choices

True

False

 

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Question 90.5 pts

Nondisjunction can lead to someone having more than two X chromosomes.

Group of answer choices

True

False

 

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Question 100.5 pts

Males function normally with only one X chromosome.  What ensures that females function normally even though they have two X chromosomes?

Group of answer choices

incomplete dominance

incomplete penetrance

epistasis

X inactivation

 

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Question 110.5 pts

Which of the following statements about X-linked recessive disorders is/are true?

Group of answer choices

They are all true

males receive the disease allele from their mothers

it takes two copies of the allele to see the disorder in females, but only one copy of the allele to see the disorder in males

they are more often seen in males