Name: 
 

Ch. 9-12 Review


Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

1. 
A locus is
a.
a recessive gene.
b.
an unmatched allele.
c.
a sex chromosome.
d.
the location of an allele on a chromosome.
e.
a dominant gene.
 

2. 
Which of the following statements is true?
a.
After the centromere divides, the chromatids are called chromosomes.
b.
Centromeres are separated during anaphase.
c.
During anaphase, some microtubules ratchet past each other while others shorten.
d.
Telophase is essentially the reverse of the events of prophase.
e.
all of these
 

3. 
In eukaryotic cells, which can occur during the stages of mitosis?
a.
the duplication of chromatids
b.
the replication of DNA
c.
synapsis and crossing over
d.
fragmentation and disappearance of nuclear envelope and nucleolus
e.
all of these
 

4. 
Short hair (L) is dominant to long hair (l). If a short-haired animal of unknown origin is crossed with a long-haired animal and they produce one long-haired and one short-haired offspring, this would indicate that
a.
the short-haired animal was pure-breeding.
b.
the short-haired animal was not pure-breeding.
c.
the long-haired animal was not pure-breeding.
d.
the long-haired animal was pure-breeding.
e.
none of these can be determined with two offspring.
 

5. 
If R is dominant to r, the offspring of the cross of RR with rr will
a.
be homozygous.
b.
display the same phenotype as the RR parent.
c.
display the same phenotype as the rr parent.
d.
have the same genotype as the RR parent.
e.
have the same genotype as the rr parent.
 

6. 
Chromatids that are attached at the centromere are called what kind of chromatids?
a.
mother
b.
daughter
c.
sister
d.
programmed
e.
either mother or daughter.
 

7. 
Which of the following statements is true?
a.
Darwin did not know which mechanisms were responsible for the variation he saw.
b.
The blending theory of inheritance provides excellent support for evolution.
c.
Darwin received Mendel's paper but did not understand its significance.
d.
The explanation for genetics had no implications for evolution.
 

8. 
Which is NOT a typical site for the occurrence of meiosis?
a.
plant ovary
b.
plant root cells
c.
human testis
d.
human ovary
e.
plant anther
 

9. 
Sister chromatids are separated from each other during
a.
metaphase I.
b.
anaphase I.
c.
telophase II.
d.
anaphase II.
e.
metaphase II.
 

10. 
When a cell undergoes mitosis,
a.
the daughter cells have identical genes.
b.
the daughter cell has genes identical to those of the mother cell that produced it.
c.
the amount of cytoplasm in the mother cell and in each of the daughter cells is equal.
d.
there is an exact duplication and division of all of the organelles between daughter cells.
e.
the daughter cells have identical genes and the daughter cell has genes identical to those of the mother cell that produced it.
 

11. 
Crossing over
a.
increases variability in gametes.
b.
results in only one exchange per homologue.
c.
occurs between sister chromatids.
d.
prevents genetic recombination.
e.
is followed immediately by separation of each of the chromatids.
 

12. 
A karyotype
a.
compares one set of chromosomes to another.
b.
is a visual display of chromosomes arranged according to size.
c.
is a photograph of cells undergoing mitosis during anaphase.
d.
of a normal human cell shows 48 chromosomes.
e.
cannot be used to identify individual chromosomes beyond the fact that two chromosomes are homologues.
 

13. 
Cells with two of each kind of chromosome are described by the term
a.
polyploid.
b.
diploid.
c.
triploid.
d.
haploid.
e.
tetraploid.
 

14. 
Karyotype analysis
a.
is a means of detecting and reducing mutagenic agents.
b.
is a surgical technique that separates chromosomes that have failed to segregate properly during meiosis II.
c.
is used in prenatal diagnosis to detect chromosomal mutations and metabolic disorders in embryos.
d.
substitutes defective alleles with normal ones.
e.
all of these
 

15. 
The chromosomes and genes are actually replicated during
a.
anaphase.
b.
metaphase.
c.
interphase.
d.
prophase.
e.
telophase.
 

16. 
Which of the following statements is false?
a.
There are more than 1,000 chromosomes found in some organisms.
b.
The more highly evolved a species is, the more chromosomes it possesses.
c.
The number of chromosomes remains constant throughout a life cycle.
d.
The number of chromosomes is the same for all members of a species.
e.
There are half as many chromosomes in germ cells as there are in somatic cells.
 

17. 
With respect to chromosomes, the difference between normal human males and females is defined by which of the following?
a.
In females, one X is deleted.
b.
Females possess one X and one Y.
c.
In males an X is replaced by a Y.
d.
Females have three X's.
e.
Males have two X's and a Y.
 

18. 
Which of the following is a transfer of genes between nonhomologous chromosomes?
a.
crossing over
b.
aneuploidy
c.
trisomy
d.
translocation
e.
duplication
 

19. 
Gene A occurs on chromosome #5, gene B occurs on chromosome #21. Therefore, these two portions of the chromosomes CANNOT be
a.
genes.
b.
dominant.
c.
loci.
d.
alleles.
e.
recessive.
 

20. 
An autosomal recessive disorder
a.
requires that only one parent be a carrier.
b.
displays its symptoms only in heterozygotes.
c.
is more frequent in males than females.
d.
will appear only in children of parents who both carry the gene.
e.
is dominant in females.
 

21. 
Which of the following will NOT develop into a gamete?
a.
spermatogonium
b.
polar bodies
c.
oocyte
d.
spermatid
e.
secondary spermatocyte
 

22. 
Which of the following events does NOT occur in prophase II, but does occur in prophase I?
a.
crossing over
b.
synapsis
c.
spindle formation
d.
crossing over and synapsis only
e.
crossing over, synapsis, and spindle formation.
 

23. 
A pine tree is called a sporophyte because it
a.
develops from a germinated spore.
b.
produces spores by meiosis.
c.
is haploid.
d.
undergoes fertilization.
e.
reproduces by both sexual and asexual means.
 

24. 
Linkage mapping is a technique that determines
a.
the relationship between chromatids.
b.
the positions of genes on chromosomes relative to one another.
c.
the positions of chiasmata.
d.
the sex of offspring.
e.
the probability of a deletion.
 

25. 
Which of the following genotypes is homozygous?
a.
AaBB
b.
aABB
c.
aaBB
d.
aaBb
e.
AaBb
 

26. 
Which of the following is NOT necessary for spindle apparatus formation?
a.
microtubules
b.
proteins
c.
centrioles
d.
microtubule organizing centers
e.
tubulins
 

27. 
Concerning the sex chromosomes, which of the following is correct?
a.
The Y chromosome carries a greater number of nonsexual traits.
b.
X and Y are different in size but carry nearly equal numbers of genes.
c.
The X chromosome carries more genes for nonsexual traits.
d.
The X chromosome carries only gender-related genes.
e.
The X chromosome carries the TDF gene.
 

28. 
If short hair (L) is dominant to long hair (l), animals LL and Ll have the same
a.
parents.
b.
genotypes.
c.
phenotypes.
d.
alleles.
e.
genes.
 

29. 
If all the offspring of a testcross are alike and resemble the organism being tested, then that parent is
a.
homozygous dominant.
b.
homozygous recessive.
c.
heterozygous.
d.
recessive.
e.
incompletely dominant.
 

30. 
Which of the following does NOT produce variation?
a.
crossing over
b.
random alignment of chromosomes during meiosis
c.
asexual reproduction
d.
genetic recombination of alleles
e.
sexual reproduction
 

31. 
Sex chromosomes
a.
determine gender.
b.
vary from one sex to another.
c.
carry some genes that have nothing to do with sex.
d.
were unknown to Mendel.
e.
all of these
 

32. 
Which of the following statements is false?
a.
Crossing over tends to reduce the frequency that two linked genes are inherited together.
b.
Independent assortment of homologous chromosomes during meiosis increases variation.
c.
Crossing over leads to variation.
d.
Abnormal number or structure of chromosomes may influence the course of evolution.
e.
The closer together genes are found on a chromosome the greater is the chance that crossing over will occur between them.
 

33. 
DNA coding regions that affect the same trait are called
a.
homologues.
b.
alleles.
c.
autosomes.
d.
loci.
e.
gametes.
 

34. 
Genes are
a.
located on chromosomes.
b.
inherited in the same way as chromosomes.
c.
arranged in linear sequence on chromosomes.
d.
assorted independently during meiosis.
e.
all of these
 

35. 
Which of the following is NOT true of spindles?
a.
They are permanent cell structures.
b.
They interact with kinetochores.
c.
Some of their microtubules overlap at the cell equator.
d.
Tubulin is the main component.
e.
Their subunits continually change.
 

36. 
Chromosomal aberrations can be produced by exposure to
a.
viruses.
b.
radiation.
c.
various chemicals.
d.
viruses and radiation, only.
e.
viruses, radiation, and various chemicals.
 

37. 
Which statement is true of the behavior of chromosomes in mitosis?
a.
Each new cell receives half of the number of chromosomes in the original cell.
b.
Each new cell receives copies of all the original chromosomes.
c.
If the original number of chromosomes was 46, each new cell will have 23..
d.
The sister chromosomes are not identical due to breakages in the DNA..
e.
All chromosomes are duplicated except the sex chromosomes.
 

38. 
Sperm are formed from the direct maturation of
a.
sperm mother cells.
b.
spermatids.
c.
spermatogonial cells.
d.
primary spermatocytes.
e.
secondary spermatocytes.
 

39. 
If a parent cell has 16 chromosomes, how many sister chromatids will be present after duplication of the chromosomes?
a.
64
b.
32
c.
16
d.
8
e.
4
 

40. 
Hemophilia
a.
is rare in the human population.
b.
is more common among men.
c.
was common in English royalty.
d.
is an X-linked recessive trait.
e.
all of these
 

41. 
Various forms of a gene at a given locus are called
a.
chiasmata.
b.
alleles.
c.
autosomes.
d.
loci.
e.
chromatids.
 

42. 
Red-green color blindness is an X-linked recessive trait in humans. A color-blind woman and a man with normal vision have a son. What is the probability that the son is color blind?
a.
100 percent
b.
75 percent
c.
50 percent
d.
25 percent
e.
0 percent
 

43. 
The F2 phenotypic ratio of a monohybrid cross is
a.
1:1.
b.
2:1.
c.
9:3:3:1.
d.
1:2:1.
e.
3:1.
 

44. 
A woman is diagnosed to have the genetic disease known as Huntington's disorder. It is a rare defect caused by an autosomal dominant allele. The chance for any one of her children to inherit the disease is
a.
dependent on the sex of the child.
b.
1/3.
c.
1/2.
d.
3/4.
 

45. 
If meiosis did NOT occur in sexually reproducing organisms,
a.
growth of the zygote would be halted.
b.
mitosis would be sufficient.
c.
gametes would be haploid.
d.
the chromosome number would double in each generation.
e.
eggs would be haploid, but sperm would be diploid.
 



 
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