GENETICS - BIOL 7 EXAM I -
September 20, 2005 NAME:
DO NOT USE ANY OTHER PAPER AT ANY TIME WITHOUT INSTRUCTOR PERMISSION
Part I: [37 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 point
each
1. When two genes are on different chromosomes, we use
independent event probability analysis (4 x 4 Punnett square) for
dihybrid crosses because
a. our
sample size will be small enough that errors will not matter much
b.
Dr. Schmeidler said it is a good method for this class
c. the sum
rule works well most of the time
d. the
product rule works gives the best results
e. the
chromosomes assort independently during meiosis
2. In meiosis, tetrads can be seen during
a. prophase
b.
metaphase
c. anaphase
d.
telophase
e. all of
the above
f. none of
the above
3. New alleles formed by mutation(s) may result in
a. no
function
b. new
function (a protein with an altered, or new function)
c. less
function
d. no
change in function
e. all of
the above
f. none of
the above
4. Mendel did NOT infer or deduce
a. the
existence of genes
b. genes
(alleles) are in pairs
c. the
principal of segregation
d.
parental equivalence
e. double
helix nature of DNA
5. Two strands of nucleotides are held together by
a. purines
b.
covalent bonds
c.
pyrimidines
d.
phosphate bonds
e.
hydrogen bonds
6. In which stage of mitosis does crossing over occur?
a. prophase
b. metaphase
c. anaphase
d. telophase
e. none of the
above
7. Given a cross between AAQqTtGgBbDd x AaQqTtggbbDd what is the
chance of an offspring expressing the dominant trait for all of these
loci?
a. 0
b. 3/4
c. 1/6
d. 27/256
e. 1/64
8. Of the following, the least good candidate for use in genetics
(inheritance) experiments is
a. tigers
b. yeast
c.
bacteria
d. flies
e. ants
9. Briefly explain your answer to # 8
10. A DNA molecule is made up of 20.62% adenine. How much
thymine will it contain?
a. 10.31%
b. 41.24%
c. 20.62%
d. 79.38%
e. not
enough information given
f. none of
the above
11. As a result of the S phase of the cell cycle, each chromosome
becomes a pair of
a. sister
chromatids
b.
daughter chromatin
c.
daughter cells
d.
daughter chromosomes
e.
homologous chromosomes
12. DNA and RNA are similar in terms of their
a. oxygen
content
b.
sugar-phosphate bonds
c.
nitrogenous bases
d. function
e. number
of strands typically present
13. Which of the following are diploid?
a. plants
b. animals
c. bacteria
d. most
multicellular plants and animals, for at least part of their life cycle
e. all
organisms, for at least part of their life cycle
f. all of
the above
14. A dihybrid testcross (crossing individuals homozygous at the
2 loci x heterozygotes at the 2 loci) will result in a genotype ratio of
a. 9:3:3:1
b. 2:4:4:2
c. 1:1:1:1
d. 1:2:1
e.
1:2:1:2:4:2:1:2:1
15. Synapsis is
a. pairing
of homologs
b.
splitting of the centromere of sister chromatids
c. base
pairing of DNA nucleotides
d. cell
division that occurs after mitosis
e. cell
division that occurs after meiosis
16. Chromosomes are composed of
a.
chromomere
b. DNA +
RNA
c.
chromatin
d. RNA +
protein
e.
centromere
17. Consider parent A with genotype AABBCCDDEE; if parent A is
crossed with parent B who is homozygous recessive for all loci, the
probability of having heterozygous offspring (F1) for all loci is:
a. 0
b ¼
c. ½
d. 1
e. not
enough information is given
18. If the F1 generation from above question were crossed, what
is the probability of having offspring which are heterozygous for all
loci?
a. 0
b. 1/8
c. 1/16
d. 1/32
e. 1/64
19. Individuals with identical alleles for a particular
gene are
a.
homozygous
b.
homosexual
c.
homologous
d.
homogenic
e.
impossible; alleles vary too much
20. In eukaryotes, ribosomes translate in (on) the
a.
cytoplasm
b. rough
endoplasmic reticulum
c.
nucleolus
d. a and b
e. all of
the above
21. Genetic variation results from
a.
crossing-over
b. mutation
c.
independent assortment of genes
d. random
segregation of alleles
e. all of the
above
22. A specific site on a chromosome is a
a. marker
b. locus
c. gene
d. allele
e. homolog
23. An aneuploid human cell could
contain
chromosomes
a. 23
b. 47
c. 46
d. any of
the above
e. none of
the above
24. In mitosis, tetrads can be seen during
a. prophase
b.
metaphase
c. anaphase
d.
telophase
e. all of
the above
f. none of
the above
25. Which of the following is FALSE ?
a. RNA and
DNA do not contain the same sugar component
b. RNA
consists of the same four nitrogenous bases as DNA
c. thymine
in DNA is replaced with pyrimidine uracil in RNA
d. RNA and
DNA have an intrinsic helical structure which is stabilized by
H-bonding between bases
e. DNA and
RNA are heteropolymers of nucleotides, each made of three components
26. A group of organisms which look the same physically and
genetically generation after generation describes
a. the
first filial generation
b. the
second filial generation
c. a pure
line
d.
parental equivalence
e.
monoecious organisms
27. Mendelian ratios are not apparent in pedigrees because
a. Mendel
did not study pedigrees in his pea experiments
b.
pedigrees involve small sample sizes
c.
pedigree charts map autosomal dominant traits that do not follow
Mendel’s ratio
d. mating between relatives generally run a higher risk of
producing recessive disorder than do mating between non-relatives
e. none of
the above
28. True or False (circle one): I am currently
aware that Dr. Schmeidler’s office hours have been chnged from
Thursday 4-5:30 pm to Monday 8-9:30 am.
29. A normal cell spends most of its time in
a. G-1
b. G-2
c. prophase
d. DNA
synthesis
e. mitosis
30. A nucleotide is composed of
a. a
nitrogenous base, a sugar, and one or more phosphate groups
b. a
nitrogenous base and a sugar
c. one
purine, one pyrimidine and a phosphate group linking them
d. one
purine, one pyrimidine and hydrogen bonds linking them
e. a sugar
and a phosphate group
31. Genes on the same chromosome are
a.
independent
b. linked
c. coupled
d.
homologous
e. alleles
32. Given a cross between AaQqTTGgbbDd x AaqqTtggBbDd what is the
chance of an offspring heterozygous at all of these loci?
a. 0
b. 1/2
c. 1/6
d. 1/64
e. 1/512
33. A 3:1 ratio describes
a. the
genotypic ratio resulting from a monohybrid cross
b. random
segregation
c. the
phenotypic ratio resulting from a monohybrid cross
d. first
filial generation
e. the
result of tossing a coin 3 times
34. In anaphase I,
a.
identical chromosomes are separated
b. a cell
divides into 2 daughter cells
c.
homologous chromosomes pair to form groups of four chromatids
d.
homologous chromosomes come to rest next to each other
e.
homologous chromosomes are separated
35. The term "wild type" indicates
a.
organisms found outside captivity
b.
organisms out of control
c.
organisms particularly prone to mutate
d. the
accepted "standard" strain of an organism, or allele of a gene
(genotype or phenotype)
e.
organisms which breed true
36. Which of the following is FALSE of homologous
chromosomes: they
a. contain
the same set of genes
b. conform
to the same size and shape
c. pair
during meiosis
d. are
inherited from the same parent
e. are
replicated before mitosis
37. Parental equivalence, describe by Mendel
a. has
since been disproved
b. means
that the genotypes and phenotypes in the progeny of a cross are the
same whether the male or female parent was dominant or recessive
c. means
that the male and female parents donate the same information to the
next generation
d. a and b
e. all of
the above
Part II: [15 points] omit three Define, explain, and/or
illustrate each of the following terms: be sure that you have both
explained the meaning of each of the terms and distinguished each from
other terms in the group. Be sure to include both the similarity
and the distinction. 3 points each
a. gene - allele
b. chromatin - chromosome
c. sister chromatid - homologous chromosome
d. DNA - RNA
e. monohybrid cross - dihybrid cross
f. homozygous – heterozygous
g. DNA - chromosome
h. dominant - recessive
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]
III. [48 points] Answer each question completely and clearly.
variable credit
1. Consider a cell with 1n = 2; one large metacentric chromosome
& one small telocentric one. Diagram,
being sure to demonstrate both the differences and similarities between
the two processes. Use colored pencil or pen (or whatever) to
keep track of the homologous chromosomes originally maternal and
paternal (with respect to this cell). Remember to indicate other
relevant cellular structures throughout the processes. 18 pts
a. mitosis
b. meiosis
2. What is the probability of the following combinations in a
family of 5 offspring from two parents heterozygous at all loci under
study (always assuming no cheating or "unfair" circumstances):
[put actual answer on the line; show work for possible partial credit]
6 pts
a. 2 males
b. 2 dominant phenotype offspring
c. 2 recessive phenotype offspring
3. What is the probability of (always assuming no cheating
or "unfair" circumstances): [put actual answer on the line; show work
for possible partial credit] 10 pts
a. tossing two coins at the same time
and getting one heads and one tails?
b. tossing two coins at the same time
and getting both tails?
c. throwing three dice, and
getting a 6 on one, an odd number on one, & a 4 or 5 on one
d. one recessive and one dominant
phenotype in the F2 of a dihybrid cross (assume P are homozygous)
e. recessive phenotype in the F2 of a
monohybrid cross (assume P are homozygous)
4. Fill in the following table. Show your work for possible
partial credit; if you choose to do this, be sure that your work is
legible and labeled sufficiently clearly to be understood by someone
other than yourself. Be sure to list the genotypes &
phenotypes in a sensible order in the first column, and then to use the
table as a table. 14 pts
|
AaBb x AaBb |
AB/ab x Ab/aB |
Ab/aB b x Ab/aB
|
AB/ab x AB/ab |
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