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Bio3:
Midterm 3 Study Guide - Fall 2006
Topics:
The
midterm will cover the lecture topics
for chapters 8-10.
- mitosis and meiosis
- genetics (Punnett squares, test cross, sex-linked genes, etc.)
- inheritance patterns
- structure of DNA and RNA
- processes of transcription and translation
1. Which one of the
following is a difference between sexual and asexual reproduction?
a. Cell division only occurs after sexual reproduction.
b. Only offspring from asexual reproduction inherit traits from two parents.
c. Sexual reproduction typically includes the development of unfertilized eggs.
d. Sexual reproduction is more likely to increase genetic variation than is
asexual reproduction.
e. Only asexual reproduction results from the union of a sperm and an egg.
2. Which one of the
following is FALSE?
a. Prokaryotic chromosomes are more complex than those of eukaryotes.
b. Most prokaryotes reproduce by binary fission.
c. Prokaryotic cells are generally smaller and simpler than eukaryotic cells.
d. In prokaryotes, most genes are carried on a circular DNA molecule.
e. Daughter prokaryotic chromosomes are separated by some sort of active
movement away from each other and the growth of new plasma membrane between
them.
3. The process by which the
cytoplasm of a eukaryotic cell divides to produce two cells is called:
a. interphase.
b. cytokinesis.
c. metaphase.
d. anaphase.
e. prophase.
4. Which of the following
occurs during interphase?
a. condensing of the chromosomes
b. duplication of the chromosomes
c. separation of chromosomes
d. cytokinesis
e. lining up of chromosome along the center of the cell
5. When animal cells are
grown in a petri dish, they typically stop dividing once they have formed a
single, unbroken layer on the bottom of the dish. This arrest of division is an
example of:
a. cancer.
b. cell constraint.
c. density-dependent inhibition.
d. cell division repression.
e. growth factor desensitization.
6. Which one of the
following is NOT a function of mitosis? Mitosis helps organisms
a. grow.
b. regenerate lost parts.
c. reproduce asexually.
d. repair tissues.
e. All of the choices are correct.
7. Which of the following
statements is FALSE?
a. Meiosis only occurs in the ovaries and testes.
b. All sexual life cycles involve an alternation of diploid and haploid stages.
c. Mitosis produces daughter cells with half the number of chromosomes as the
parent cell.
d. A normal human zygote has 46 chromosomes (23 pairs).
e. A haploid cell has half the chromosomes of a diploid cell.
8. During which stage of
meiosis do synapsis and the formation of tetrads occur?
a. interphase I
b. prophase I
c. interphase II
d. prophase II
9. Independent orientation
of chromosomes at metaphase I results in an increase in the number of:
a. gametes.
b. homologous chromosomes.
c. possible combinations of characteristics.
d. sex chromosomes.
e. points of crossing over.
10. If a chromosome fragment
breaks off and then reattaches to the original chromosome but in the reverse
direction, the resulting chromosomal abnormality is called a(n):
a. deletion.
b. inversion.
c. translocation.
d. nondisjunction.
e. reciprocal translocation.
11. Mendel conducted his
most memorable experiments on:
a. peas.
b. roses.
c. guinea pigs.
d. fruit flies.
e. clones.
12. Which one of the
following is FALSE?
a. The genetic makeup of an organism constitutes its genotype.
b. An organism with two different alleles for a single trait is said to be
heterozygous.
c. Alleles are alternate forms of a gene.
d. An allele that is fully expressed is referred to as recessive.
e. The expressed physical traits of an organism are called its phenotype.
13. A carrier of a genetic
disorder who does not show symptoms is most likely to be __________ to transmit
it to offspring.
a. heterozygous for the trait and able
b. heterozygous for the trait and unable
c. homozygous for the trait and able
d. homozygous for the trait and unable
14. Imagine that beak color
in a finch species is controlled by a single gene. You mate a finch homozygous
for orange (pigmented) beak with a finch homozygous for ivory (unpigmented) beak
and get numerous offspring, all of which have a pale, light orange beak. This
pattern of color expression is most likely to be an example of:
a. incomplete dominance.
b. codominance.
c. pleiotropy.
d. polygenic inheritance.
e. crossing over.
15. A person with AB blood
illustrates the principle of:
a. incomplete dominance.
b. blending inheritance.
c. pleiotropy.
d. polygenic inheritance.
e. codominance.
16. How many sex chromosomes
are in a human gamete?
a. one
b. two
c. three
d. four
e. five
17. Any gene located on a
sex chromosome:
a. is called a recessive gene.
b. is called a dominant allele.
c. is called a sex-linked gene.
d. will exhibit pleiotropy.
e. will exhibit codominance.
18. Explain the difference
between complete dominance, codominance and incomplete dominance.
Give an example of each type of inheritance pattern.
19. You conduct a cross
between two flowers for flower color. If the genotypes of the parent flowers
are: Pp x Pp, what are resulting genotypes and their proportions in the
offspring?
(Note: Purple (P) is dominant and white (p) is recessive)
20. You conduct a cross
between two flowers for flower color and plant height. If the genotypes of the
parent flowers are: ppTt x PpTt, what are resulting phenotypes and their
proportions in the offspring?
(Note: Purple (P) is dominant and white (p) is recessive; tall (T) is dominant
and short (t) is recessive)
21. Color blindness is a
recessive sex-linked trait. A
color-blind woman marries a man with normal vision.
Can this couple have a color-blind daughter?
Why or why not? (Note: N= normal vision; n= color-blindness)
22. The monomers of DNA and
RNA are:
a. amino acids.
b. monosaccharides.
c. nucleotides.
d. fatty acids.
e. triglycerides.
23. Which of these is always
true with regard to a DNA double helix?
a. The amount of adenine is equal to the amount of uracil, and the amount of
guanine is equal to the amount of cytosine.
b. The amount of adenine is equal to the amount of thymine, and the amount of
guanine is equal to the amount of uracil.
c. The amount of adenine is equal to the amount of guanine, and the amount of
thymine is equal to the amount of cytosine.
d. The amount of adenine is equal to the amount of cytosine, and the amount of
guanine is equal to the amount of thymine.
e. The amount of adenine is equal to the amount of thymine, and the amount of
guanine is equal to the amount of cytosine.
24. The shape of a DNA
molecule is most like:
a. a set of railroad tracks.
b. a diamond ring.
c. a twisted rope ladder.
d. a gold necklace.
e. the letter X.
25. Experiments have
demonstrated that the "words" of the genetic code (the units that
specify amino acids) are:
a. single nucleotides.
b. two-nucleotide sequences.
c. three-nucleotide sequences.
d. nucleotide sequences of various lengths.
e. enzymes.
26. A base substitution
mutation in a gene sometimes does not result in a different protein.
Which of the following factors could account for this?
a. the mutation affects only the sequence of the protein's amino acids, so the
protein stays the same
b. the rarity of such mutations
c. a correcting mechanism that is part of the mRNA molecule
d. the fact that such mutations are usually accompanied by a complementary
deletion
e. some amino acids are produced from more than one codon
27. Translation consists of
which of the following?
a. the conversion of genetic information from the language of nucleic acids to
the language of proteins
b. the conversion of genetic information from DNA nucleotides into RNA
nucleotides
c. the addition of nucleotides to a DNA template
d. the conversion of genetic information from the language of proteins to the
language of enzymes
e. DNA replication
28. Which one of the
following best describes the sequence of events of translation?
a. codon recognition → translocation → peptide bond formation
→ termination
b. peptide bond formation → codon recognition → translocation
→ termination
c. codon recognition → peptide bond formation → translocation
→ termination
d. codon recognition → peptide bond formation → termination →
translocation
e. peptide bond formation → translocation
→ codon recognition → termination
29. Any change in the
nucleotide sequence of DNA is called a(n):
a. mutation.
b. advantage.
c. codon.
d. translation.
e. anticodon.
Answers:
1. D
7. C
13. A
2. A
8. B
14. A
3. B
9. C
15. E
4. B
10. B
16. A
5. C
11. A
17. C
6. E
12. D
18. Complete dominance: the phenotypes of the heterozygote and the
dominant homozygote are identical. Example:
any of Mendel’s pea traits.
Incomplete
dominance: the heterozygote has an
intermediate phenotype Example:
pink flower color of the heterozygote in snapdragons and carnations.
Codominance:
both alleles are equally expressed in the phenotype of the heterozygote.
Examples: AB blood type in humans; M, N and MN blood group in humans
19.
Genotypic ratios: ¼ PP, ½ Pp, ¼ pp
20.
|
|
PT
|
Pt
|
pT
|
pt
|
|
pT
|
PpTT
|
PpTt
|
ppTT
|
ppTt
|
|
pt
|
PpTt
|
Pptt
|
ppTT
|
pptt
|
Phenotypic ratios: 3/8
purple & tall, 3/8 white & tall, 1/8 purple & short, 1/8 white &
short
21. No, because a
color-blind daughter would need to have the genotype XnXn
so she would need two copies of Xn.
She will inherit one copy from her mother since the mother’s genotype
is XnXn, but her father has genotype XNY since
he has normal vision. So the
daughter will have genotype XNXn and will have normal
vision.
22. C
23. E
24. C
25. C
26. E
27. A
28. C
29. A
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