Human Genetics and Medicine - BIOL 72 EXAM II -
March 10, 2011 NAME:
DO NOT USE ANY OTHER PAPER AT ANY TIME WITHOUT INSTRUCTOR PERMISSION
Part I: [45 points] Choose the one BEST answer. Circle
its letter. Read each question and all 5 choices carefully because
more than one answer might seem correct at first glance.
1.25 point each
1. The degrees of freedom for analyzing the genotypes for one
gene is
a. 1
b. 2
c. 3
d. 4
e. 5
2. Retrospective analysis methods include
a. graphing or plotting data
b. χ2 analysis [χ is the Greek
letter “chi”]
c. developing a revised hypothesis
d. a and b
e. all of the above
3. The human fertilized egg (zygote) contains
chromosomes
a. 92
b. 22
c. 46
d. 23
e. 44
4. Biological macromolecules include
a. nucleic acids, proteins, carbohydrates,
lipids
b. sugars, amino acids, DNA, RNA, fat
c. any long chain of carbons
d. a and b
e. all of the above
5. Assuming that we start with diploid cells, the result of
mitosis is
a. 1 2N daughter cell
b. 2 1N daughter cells
c. 2 2N daughter cells
d. 4 1N daughter cells
e. 4 2N daughter cells
6. Prospective analysis methods include
a. working out probability problems
b. using the binomial expansion and
Pascal’s triangle
c. thinking about what one expects to
happen under specific circumstances
d. a and b
e. all of the above
7. There are nuclear
divisions during meiosis
a. 1
b. 2
c. 3
d. 4
e. a different number each time, depending
on circumstances
8. In order to analyze the class coin toss data,
a. prospective analysis is used to predict
outcomes
b. χ2 analysis can be used to decide
whether individual tossed their coins fairly
c. χ2 analysis is more accurate for the
data from the entire class than for any individual
d. a and b
e. all of the above
9. The term "wild type" indicates
a. organisms found outside captivity
b. the accepted "standard" strain of an organism,
or allele of a gene (genotype or phenotype)
c. organisms particularly prone to mutate
d. organisms out of control
e. organisms which breed true
10. χ2 analysis takes into account
a. predictions based on prospective
analysis
b. expected ratios
c. sample size
d. a and b
e. all of the above
11. Meiosis produces
a. gametes
b. somatic cells
c. all cells of the body
d. X and Y chromosomes
e. autosomes
12. A man with a rare recessive disorder marries a woman who
is phenotypically normal. If the woman is homozygous at that
locus, the probability that their offspring will have the disorder
is
a. 0% because the disease is rare
b. 0% because the child will receive a dominant
allele from the mother
c. 100% because the child would receive the trait
from the father
d. 50%
e. 25%
13. A child of the parents described above marries a
heterozygote at this locus. The probability that they will have a
child with the disorder is:
a. 0% because the disease is rare
b. 0% because the child will receive a dominant
allele from the mother
c. 100% because the child would receive the trait
from the father
d. 50%
e. 25%
14. To identify the genotype of yellow-seeded pea plants as
either homozygous dominant (YY) or heterozygous (Yy), one would do a
test cross using plants of genotype
a. y
b. Y
c. yy
d. YY
e. Yy
15. You obtain a sample chi-square value of χ2 = -5.49, from
which can be inferred that
a. observed frequencies are lower than the
expected frequencies across all cells
b. there is a negative association between
your two variables
c. you have made a calculation error;
chi-square values cannot be negative
d. the observed frequencies are higher than
the expected frequencies for at least half of your rows
e. the sample size was too small
16. Two people of normal phenotype have had a child with
Niemann-Pick disease, a lethal recessive trait. What is the
probability that their next child will be afflicted?
a. 1 (100%)
b. 1/2 (50%)
c. 1/4 (25%)
d. 3/4 (75%)
e. not possible to predict from information given
17. A phenotypic ratio of 3:1 among offspring of a cross
between two organisms heterozygous for a single gene is expected
when
a. the alleles separate randomly and
independently during meiosis
b. each allele contains two mutations
c. the alleles are identical
d. the alleles are incompletely dominant
e. only recessive traits are scored
18. Non-disjunction can occur during
a. the first meiotic event
b. the second meiotic event
c. spermatogenesis
d. oogenesis
e. a and b
f. c and d
g. all of the above
19. The number of chromosomes in a gamete (any gamete) is
a. 1N
b. 2N
c. 4N
d. 46
e. 23 pairs
20. The degrees of freedom for analyzing the phenotypes for
one gene is
a. 1
b. 2
c. 3
d. 4
e. 5
21. The p and q terms in the binomial expansion or Pascal’s
triangle represent
a. the probability of outcome 1 = p and the
probability of any other outcome = q
b. the exponent of p represents the number
of occurrences of outcome 1
c. the exponent of q represents the number
of occurrences of not-outcome 1
d. n = the line number = the number of
attempts in a group
e. all of the above
22. An organism's expressed physical trait, such as seed color
or pod shape, is its
a. genotype
b. cytosol
c. phenotype
d. gamete
e. trait
23. A description of an individual's alleles is called its
a. phenotype
b. genotype
c. DNA
d. RNA
e. genome
24. When writing out a Pascal’s triangle,
a. there is a 1 at both ends of each line,
and only for the first and last terms in each line
b. the number of the line (n) is the 2nd
and the 2nd to the last numbers of that line
c. each other number (in the middle of the
line) is the sum of the 2 numbers diagonally above it
d. a and b
e. all of the above
25. A chromosome with its centromere located in the middle is
a. metacentric
b. telocentric
c. submetacentric
d. acrocentric
e. holocentric
26. Assuming that we start with diploid cells, the result of
meiosis is
a. 1 2N daughter cell
b. 2 1N daughter cells
c. 2 2N daughter cells
d. 4 1N daughter cells
e. 4 2N daughter cells
bonus: Write a question that you studied for, and forgetful me, I
neglected to ask. Answer your question. PLEASE ask
yourself something you can answer well! PLEASE answer the
question you actually ask. [up to 5 points awarded based on
question & answer] Part Ib. For each of the following
specify the cell cycle stage at which the event occurs: choices
are: Go , G1 , G2 , S, or prophase, metaphase, anaphase,
telophase: for these, specify - mitosis, I, II, or any/all; does not
happen at all. If more than one answer is correct, include all
correct terms.
1. Chromatin
condenses
2. Homologous
chromosomes come together and align
3. Sister
chromatids separate
4. DNA is
replicated; sister chromatids are formed
5. Diploid nuclei
form
6. Homologous
chromosomes segregate
7. Tetrads line
up at equator
8. Cells are
engaged in normal cellular behavior and growth
9. Haploid nuclei
form
10. Fertilization
Part II: [ 15 points] What is the probability of (always
assuming no cheating or "unfair" circumstances): [put actual answer
on the line; show work for partial credit (if correct)]
1. tossing a coin
twice and getting one heads and one tails?
2. tossing a
penny and a nickel at the same time and getting heads on the penny
and tails on the nickel?
3. tossing two
coins at the same time and getting both heads?
4. tossing two
coins at the same time and getting one heads and one tails?
5. throwing two
dice, and getting a 2 on one & a 1 or 3 on the other?
6. throwing two
dice, and getting both 5's?
7. throwing two
dice, and getting a sum of 5?
8. tossing three
identical coins at the same time and getting one heads and two
tails?
9. drawing
a jack from a well shuffled complete deck of cards?
10. drawing
a spade from a well shuffled complete deck of cards and rolling a 5
on a single die ?
Extra Credit. the person to your right being female [ if you
are in the seat the furthest to the right, use "the person to your
left" ]?
Part III: [ 15 points] While you are working as a
genetic counselor, a couple asks you for advice. They have had
one child who died of Tay Sachs, a lethal recessive disorder.
They hope to have more children, and want to know: [put
actual answer on the line; show work for partial credit (if
correct)]
a. What is the chance that their next child will
have Tay Sachs?
b. If their next child is healthy, what is
the chance that the third child will be healthy as well?
c. What is the chance of their having four normal
children, in their next four attempts?
d. What is the chance of their having four normal
girls, in their next four attempts?
e. If there is a
prenatal test for Tay Sachs, why might this couple chose to have
such a test done with subsequent pregnancies? That is, for
what purpose would such a test be done?
Part IV: [ 25 points] For each of the following, draw the
simplest possible Punnett square which completely demonstrates all
the possible outcomes, and write out the proportions of outcome
genotypes & phenotypes (be sure that you indicate which
genotypes or phenotypes correspond to the numbers. e.g. 2Q :
5q is the same as Q : q = 2:5 ; 3QQ : 7Qq : 2qq or QQ :
Qq: qq = 3:7:2).
gamete genotypes offspring genotypes
offspring phenotypes
1. HH x hh
2. Gg
x gg
3. Qq
x Qq
4.
EeHh x eehh
5.
AaBb x AaBb