Biology 151
Fall 2008 – Prof. Hart
Midterm Exam #3 --- 40 Questions worth 2.5 points each
Correct answers shown in BOLD below questions
1) A cell with 4 different types of chromosomes (2n=8) could create how many DIFFERENT gametes?
C) 24 or 16
2) During normal gametogenesis, recombination produces genetic variation if:
B) it occurs between homologous chromosomes
Match the following terms with their definitions:
3) Independent assortment = A
4) Mendel’s Law of Segregation = D
5) Synaptonemal complex = C
6) Interkinesis = B
7) Gene linkage = E
A) paternal and maternal homologs can separate in any number of random combinations
during Meiosis
B) a rest phase between meiosis 1 & 2
C) four chromatids aligned and held together with a nucleoprotein lattice
D) alleles for the same trait separate into different gametes during meiosis
E) two genes located on the same chromosome
8) Fertility drugs like Clomid…
A) inhibit estrogen receptors in the body and thus cause ovulation.
9) During which stage of meiosis do homologous chromosomes separate?
D) anaphase I
10) Which one of the following statements is FALSE?
A) Mitosis is used for growth and tissue repair in animals.
B) Meiosis produces 4 haploid cells.
C) In mitosis, two genetically identical cells are created.
D) In meiosis, there is only one S phase.
E) All of the above statements are TRUE.
11) Amniocentesis and Chorionic Villi Sampling are both…
A) processes that obtain fetal cells so that the chromosomes can be analyzed.
12) Which of the following is NOT an example of aneuploidy?
D) An individual with a reciprocal translocation between 2 chromosomes
13) Nondisjunction during Meiosis 1 in humans will create…
A) 4 gametes, each one will have an abnormal number of chromosomes.
or
D) 2 gametes with 22 chromosomes and 2 gametes with 24.
14) If a chromosome fragment breaks off and then reattaches to a non-homologous chromosome, the
resulting chromosomal abnormality is called a(n)…
C) Robertsonian translocation.
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15) If a diploid cell has 44 chromosomes, then meiosis would create:
A) 4 cells, each one containing 22 chromosomes
16) Meiosis in men…
A) is called spermatogenesis.
17) In which way does meiosis produce genetic diversity?
E) All of the above
18) If your parents give you different alleles for a gene, then you are _____________ for that gene.
B) heterozygous
19) Which of the following is an example of a genotype?
C) You have two copies of the dominant allele for the “Freckle” gene.
20) A person who can roll their tongue (genotype Rr) is planning on having children with a person
who cannot (genotype rr). Tongue rolling is dominant over not rolling one's tongue. What are the
chances that they will have a child who cannot roll their tongue?
C) 50%
21) Tay-Sachs Disease is an autosomal recessive disease. What would be the genotype of a carrier?
B) Aa
22) A couple have just discovered that they are both carriers for the Tay-Sachs gene. What ratio
(children who will have Tay-Sachs to healthy children) would you expect them to have?
C) 1:3
23) Which of the following gametes could an individual with this genotype (AaBB) create?
C) AB or aB
24) Which of genotypes describes an individual who is homozygous dominant for hairline but
heterozygous for hitchhiker’s thumb?
Note: W=widow’s peak hairline, w=straight hairline
H= hitchhiker’s thumb, h=straight thumb
C) WWHh
25) A heterozygous person with Type B blood is planning on having children with a person who has
Type O blood. What blood types could their children have?
C) Type B or Type O
26) What are the chances that a heterozygous person with Huntington’s Disease (HD) will have a
child with the condition? Assume the other healthy parent is homozygous recessive.
B) 50% chance
27) Genes located on the Y chromosome are always...
A) passed down from the father to all of his sons.
28) Which of the following genotypes best represents a man who is red/green color-blind?
D) XaY
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29) A red/green (RG) color-blind man has children with a woman who is heterozygous for this trait.
What percentage of their children will be color blind?
C) 50% of the children will be RG color blind
30) Hypercholesteremia is determined by a gene on a(n) _______ chromosome and is a good
example of _________.
B) autosomal / incomplete dominance
Match the type of Exception to Mendel's rules (below) with an example. Use each answer ONLY
ONCE.
31) A trait like body weight where you see a range of body weights that, when lined up, form a bellshaped curve. = E
32) Type 2 Diabetes = B
33) Sometimes one gene will affect the phenotype of a completely different gene = D
34) A certain combination of alleles will never develop into a fetus = C
35) A man and a woman both inherit a defective allele that causes color-blindness but only the man is
color blind. The woman has normal vision. = A
A) Gender effects
B) Environmental effects
C) Lethal Alleles
D) Epistasis
E) Polygenic inheritance
Ogres have a gene that determines whether or not they have hair. Shrek has no hair and his genotype
is heterozygous. Fiona has hair and she is homozygous for this gene.
36) Which of the following would be accurate genotypes for them?
A) Fiona’s genotype is hh / Shrek’s genotype is Hh
37) Which of the following is the dominant phenotype for this gene?
B) Not having hair (being bald)
38) What percentage of their children will have hair?
B) 50%
Shrek and Fiona are both heterozygous for the ogre ear-shape. The ogre “ear-shape” gene and the
“hair” gene are on different chromosomes. Tube-shaped ears (E) is dominant over flat ears (e).
39) What fraction of their children will have tube-shaped ears and no hair?
B) 3/8
40) What will be the ratio of baby ogres with hair and tube-shaped ears to bald, flat-eared baby
ogres?
A) 3:1
EXTRA CREDIT 41) In class, I gave you the following dihybrid cross to do on your own: BbTt x Bbtt
Where the B/b gene has a dominant allele that gives mice brown fur and the recessive allele gives
mice gray fur and where the T/t gene has a dominant allele that gives mice long tails while the
recessive allele gives mice short tails. Which of the following statements is TRUE:
A) You can get all 4 different types of baby mice from this cross.
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