BIOL 101 Spring 2019 Exam 2 – Unit 2 Genetics
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BIOL 101 Spring 2019
Exam 2 – Unit 2 Genetics
Instructions
• Make sure you write your name and Student PID number on this exam.
• Mark or write your answers clearly on this exam. Some questions will have one correct answer and some may have multiple (questions are marked). Note that for any questions with multiple correct answers, there is no partial credit.
• When you are done, you will turn in this exam to a proctor.
• Keep your eyes on your own paper. Report any honor code violations to your professor.
• Read and sign the honor pledge below.
Honor Pledge: “I have neither given nor received any unauthorized assistance on this exam.” Your signature:____________________________________________________________ Provide your signature as verification that the above statement is true.
→EXAM QUESTIONS START HERE <
**Be sure to save about 10 minutes for the short answer questions
Each of the following questions is worth 2 points. [10 pts total]
Part II: Each of the following questions are worth 3 points [60 pts total].
→Follow instructions carefully.
6. Female Komodo dragons kept in captivity have been known to produce viable offspring, even though they have never received sperm from a male Komodo dragon. Based on what you know about meiosis and reproduction, this is an example of:
a) Sexual reproduction b) Asexual reproduction c) Not enough information
Bubble in your answer choice (choose one): A B C
7. A 45-year old man had a dark pigmented mole removed from his thigh. The doctor removed the mole and a lymph node in the area. Which of the following characteristics would define the pigmented mole cells as malignant?
a) Cells that grew on top of one another instead of in a layer
b) Cells with pigment were found in the connective tissue beneath the skin; but the lymph nodes did not have these cells.
c) Pigmented cells divided more rapidly than the normal skin cells.
d) The mole had varied colors.
e) All of these.
Bubble in your answer choice (choose one): A B C D E
8. In a cell where 2n = 16, at the end of meiosis II, there are:
cells (write a number in the box)
that are haploid diploid ill in one)
and have ___________ chromosomes. (write a number on the line)
9. Four gametes are shown to the right. Which of the following images below
shows what metaphase I looked like to give rise to these gametes?
Bubble in your answer choice (choose one):
A B C D
10. Non-disjunction occurs in a male in a cell that gives rise to sperm. The non-disjunction occurs during meiosis II and affects his sex chromosomes. Which of the following is a possible outcome if one of his abnormal sperm resulting from this non-disjunction event was fertilized with a normal haploid egg?
a) XO b) XYY c) both d) neither
Bubble in your answer choice (choose one): A B C D
11. Given the cell to the right, which of the following gametes are possible with
normal meiosis and the events that take place in normal meiosis? *You may select
more than one.
a) ABbDgrr b) ABDgr c) AbDgR d) ABDGR
Bubble in your answer choice (*you may select more than one):
A B C D
12. Below are three crosses with four different mice and the phenotypes of their offspring.
Mouse 1 (grey) x Mouse 2 (brown) → 1:1 grey to brown
Mouse 1 (grey) x Mouse 3 (brown) →all brown
Mouse 2 (brown) x Mouse 4 (brown) →3:1 brown to grey
What is the genotype of mouse 3?
a) AA b) Aa c) aa d) could be AA or Aa
Bubble in your answer choice (choose one): A B C D
13. A gene for muscular dystrophy is X linked. A female carrier and an unaffected male have one daughter together. The daughter has an unaffected male partner and they have a son together. What is the probability that their son, in this third generation, will be affected?
a) 0% b) 25% c) 50% d) 75% e) 100%
Bubble in your answer choice (choose one): A B C D E
14. Examine the pedigree to the right. What mode of inheritance is most
likely for this rare genetic disease? (Both parts of the answer must be correct;
no partial credit)
15. Wing length and eye color are encoded by two separate genes in flies; both traits exhibit complete dominance. Two pure-breeding (homozygous) flies are crossed: One has short wings and white eyes and one is wildtype (normal wings and red eyes). The F1 offspring have normal wings and
white eyes.
When two flies of this F1 generation (with normal wings and white eyes) are crossed,
what fraction would you expect to have short wings and red eyes?
Put your answer as afraction in the box to the right. (fraction)
16. A single gene with incomplete dominance controls thyroid hormone level. The “high level” allele (T) is incompletely dominant over the “low level” allele (t). A gene related to skin color on another chromosome also exhibits incomplete dominance. A dark pigment allele (P) is incompletely dominant over light pigment (p). What is the probability that the offspring from a dihybrid cross will have the medium thyroid hormone level and medium toned skin?
a) 1/4 b) 1/2 c) 3/8 d) 9/16 e) none of the choices
Bubble in your answer choice (choose one): A B C D E
A blood smear is found at the scene of a crime and theforensic lab determined that the owner of the blood was genotype IA/i. Use this information to answer questions 17 and 18 below.
17. The genotype of a single brain cell from this individual would be: (fill one box in) IA/i IA can't know for sure
18. A single sperm cell from this individual would be (fill one box in) IA/i IA can't know for sure
19. Note: There is an mRNA codon table on the lastpage. Below is the template strand sequence of a gene, showing the region of transcribed DNA between the promoter and transcription stop site:
promoter sequence--GGGTCCTGATACTAAATACCAGCTATCTCC—transcription stop
Use what you know about start and stop signals related to “information flow” to
determine how many amino acids long the final protein would be. Assume no introns
are present. (Put your number in the box to the right).
20. Using the sequence from the question above, what is the second amino acid in your protein? Write the amino acid (three letters) in the box below.
21. How many unique ways are possible to write an RNA code for the following amino acid sequence:
LYS-ALA-MET
Put your number in the box to the right.
22. Below is part of one allele found in most people in the population (mRNA sequence shown): …GCGCAAGGCAGC…
Another allele was found less frequently in the population:
… GCGCAAAGGCAGC…
Based on the information above, you can be certain that: (* more than one choice may be selected)
a) the first allele is dominant
b) the second allele is dominant
c) the two alleles produce proteins with different primary structures
Bubble in your answer choice (*more than one answer may be selected): A B C
23. Use the image of chromosomes to the right.
Are chromosomes 1 and 3 sister chromatids?
YES NO
24. Which traits, if any are polygenic? (*more than one answer may
be selected).
a) toe-pad color b) eye color
c) fur color d) tail length
e) none of the traits are polygenic
Bubble in your answer choice (*more than one answer may be
selected):
A B C D E
25. Frizzy fur (F) is completely dominant over straight fur (f) in poodles. A frizzy poodle was crossed to a straight-fur poodle and 6 puppies were frizzy and 5 had straight fur. What is the genotype of the frizzy fur parent?
a) Ff b) FF c) Ff or FF (we can’t tell)
Bubble in your answer choice (choose one): A B C
***********************************************************************
Part III. Short Answer Questions [30 points] **spend no more than 10 minute on short answer.
Read the instructions carefully. Write your answers in the designated areas. Answers outside the
designated areas will not be graded. 5 points per answer.
26. To the right is a pedigree for a muscular disease. The disease is caused by a recessive mutation in a gene on chromosome 21.
a) From which parent did the son inherit the disease gene?
The identity of the disease gene is known. Through a technique called PCR you
can determine the size of the protein-coding region of the gene.
• The affected son’s DNA produces two PCR products, both are 500 nucleotides in length.
• The father’s DNA produces two different length products: one is 200 nucleotides and one is
500 nucleotides.
• The mother’s DNA also produces two different length products: one is 200 nucleotides and one is 500 nucleotides.
b) Using the data provided, what is the probability that the sister has two PCR products both with 200 nucleotides?
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%
c) Briefly, explain your reasoning from part B.
d) The mother becomes pregnant. An amniocentesis test shows that the fetus has a Y chromosome.
What is the probability the third child has the disease?
(Please write your answer as a percent in the box to the right)
27. The graph to the right shows the results of a study in which scientists studied a gene called HGX.
They genotyped many individuals at a specific location in the HGX gene
where they noticed there was some variation in the DNA sequence.
They found that people had one of three genotypes (shown in the
three boxes as a mRNA codon at this location). They measured their
skin coloration through a melanin index.
a) Their hypothesis was that this gene, which is known to affect
eyesight, also plays a role in skin pigmentation. Do the results lend
support to their hypothesis or not? Explain your reasoning. Assume
their experimental design and data collection was well done (this is not
a question about experimental design.)
b) Scientists were examining remains from an individual found with
the CGG/CGG genotype and they concluded that this person most
likely had dark skin. Would you agree or not, and why? Put your
answer in the box below.
Congratulations and great job! You are done with this exam.
Please make sure your NAME and PID number are on the first page of this exam.
Make sure you signed the Honor Pledge on the first page.
Turn in every page, including scrap paper, before you leave the room.
2022-07-26