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AP Bio Ch. 15 Study Guide Test Your Knowledge

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

 1. 
Which of the following statements is part of the chromosome theory of inheritance?
a.
Genes are located on chromosomes
b.
Homologous chromosomes and their associated genes undergo segregation during meiosis
c.
Chromosomes and their associated  genes undergo independent assortment in gamete formation
d.
Mendel’s laws of inheritance relate to the behavior of chromosomes in meiosis
e.
all of the above
 

 2. 
A wild type is
a.
the phenotype found most commonly in nature
b.
the dominant allele
c.
designated by a small letter if it is recessive or a capital letter if it is dominant
d.
a trait found on the X chromosome
e.
your basic party animal
 

 3. 
Sex-linked traits
a.
are carried on an autosome but expressed only in males
b.
are coded for by genes located on a sex chromosome
c.
are found in only one sex, depending on the sex-determination system of the species
d.
are always inherited from the mother in mammals and fruit flies
e.
depend on whether the gene was inherited from the mother or the father
 

 4. 
In which of the following structures would you expect to find a Barr body?
a.
an egg
b.
a sperm
c.
a liver cell of a man
d.
a liver cell of a woman
e.
a mitochondrion
 

 5. 
A cross of a wild-type red-eyed female with a violet-eyed male produces all red-eyed offspring. If the gene is X-linked, which of the following should the reciprocal cross produce? (Assume the red allele is dominant to the violet allele.)
a.
all violet-eyed flies
b.
3 red-eyed flies to 1 violet-eyed fly
c.
a 1:1 ratio of red and violet eyes in both males and females
d.
red-eyed females and violet-eyed males
e.
all red-eyed flies
 

 6. 
Linkage and cytogenetic maps for the same chromosome
a.
are both based on mutant phenotypes and recombination data
b.
may have different orders of genes
c.
have both the same order of genes and intergenic distances
d.
have the same order of genes but different intergenic distances
e.
are created using chromosomal abnormalities
 

 7. 
A 1:1:1:1 ratio of offspring from a dyhybrid testcross indicates that
a.
the genes are linked
b.
the dominant organism was homozygous
c.
crossing over has occured
d.
the genes are 25 map units apart
e.
the genes are not linked or are more than 50 map units apart
 

 8. 
Genes A and B are linked and 12 map units apart. A heterozygous individual, whose parents were AAbb and aaBB, would be expected to produce gametes in which of the following frequencies?
a.
44% AB     6% Ab      6% aB    44% ab
b.
6% AB     44% Ab     44% aB     6% ab
c.
12% AB   38% Ab     38% aB    12% ab
d.
6% AB       6% Ab    44% aB     44% ab
e.
38% AB    12% Ab    12% aB    38% ab
 

 9. 
Two true-breeding Drosophila are crossed: a normal-winged, red-eyed female and a miniature-winged, vermilion-eyed male. The F1s all have normal wings and red eyes. When F1 offspring are crossed with minature-winged, vermilion-eyed flies, the following offspring resulted:
233 normal wing, red eye
247 minature wing, vermilion eye
7 normal wing, vermilion eye
13 miniature wing, red eye

From these results, you could conclude that the alleles for miniature wings and vermillion eyes are
a.
both X-linked and dominant
b.
located on autosomes and dominant
c.
recessive, and that these genes are located 4 map units apart
d.
recessive, and that these genes are located 20 map units apart
e.
recessive, and that the deviation from the expected 9:3:3:1 ratio is due to epistasis
 

 10. 
A female tortoiseshell cat is heterozygous for the gene that determines black or orange coat color, which is located on the X chromosome. A male tortoiseshell cat
a.
cannot occur
b.
is hemizygous at this locus
c.
must have resulted from a nondisjunction and has a Barr body in each of its cells
d.
must have two alleles for coat color in each of his cells, one from his father and one from his mother
e.
would be hermaphroditic
 

 11. 
When we say that a few of the genes for Mendel’s pea characters were physically linked but genetically unlinked, we mean that
a.
the genes are on the same chromosome, but they are more than 50 map units apart
b.
the genes assort independently even though the chromosomes they are on travel to the metaphase plate together
c.
their alleles segregate in anaphase 1, and each gamete receives a single allele for all of these genes
d.
dihybrid crosses with these genes produce more than 50% recombinant offspring even though they are on the same chromosome
e.
Mendel could not determine that the genes were on the same chromosome because he did not perform crosses with these gene pairs
 

 12. 
Which of the following chromosomal alterations does not alter genic balance but may affect gene expression and thus phenotype?
a.
deletion
b.
inversion
c.
duplication
d.
nonidentical duplication
e.
nondisjunction
 

 13. 
Genomic imprinting
a.
explains cases in which the phenotypic effect of an allele depends on the sex of the parent from whom that allele is inherited
b.
may involve the silencing of an allele by methylation such that offspring inherit only one active copy of a gene
c.
occurs more often in females because of the larger maternanl contribution of cytoplasm
d.
is more likely to occur in the offspring of older mothers
e.
involved both a and b
 

 14. 
Which of the following statements is not true about genetic recombination?
a.
Recombination of linked genes occurs by crossing over
b.
Recombination of unlinked genes occurs by independent assortment of chromosomes
c.
Genetic recombination results in offspring with combinations of traits that differ from the phenotypes of both parents
d.
Recombinant offspring outnumber parental type offspring when two genes are 50 map units apart on a chromosome
e.
The number of recombinant offspring is proportional to the distance between two gene loci on a chromosome
 

 15. 
Tests of social behavior given to Turner syndrome volunteers (who are XO) found a correlation between scores on “behavioral inhibition” tasks and  the source of the lone X chromosome. These test results appear to be an example of
a.
genomic imprinting of a gene on the X chromosome
b.
Y-linked inheritance
c.
meiotic nondisjunction
d.
chromosomal reciprocal translocation
e.
nonreciprocal crossover
 

 16. 
Suppose that alleles for an X-linked character for wing shape in flies show incomplete dominance. The X+ alllele codes for pointed wings, the Xr for round wings, and X+Xr individuals have oval wings. In a cross between an oval-winged female and a round-winged male, the following offspring were observed: oval-winged females, round-winged females, pointed-winged males, and round-winged males. A rare pointed-winged female was noted. Cytological study revealed that she had two XX chromosomes. Which of the following events could account for this unusual offspring?
a.
a crossover between two X chromosomes
b.
a crossover between the X and Y chromosomes
c.
a nondisjunction in meiosis II between two X+ chromatids
d.
a nondisjunction between the X and Y chromosomes, producing some sperm with no sex chromosomes
e.
Both c and d together could produce an X+X+ female when an XX egg was fertilized by a sperm in which there was no sex chromosome
 

 17. 
Some girls who fail to undergo puberty are found to have Swyer syndrome, a condition in which they are externally female but have an XY genotype. Which of the following statements may explain the origin of this syndrome?
a.
A mutation in the Xist gene, which codes for RNA molecules that coat the X chromosome and initiate X-inactivation, must have occured.
b.
A nodisjunction in the egg from the mother resulted in both sex chromosomes coming from the father. Genomic imprinting of the father’s X chromosome then caused the development of a female genotype.
c.
These individuals are actually XXY; the second X is not seen because it is condensed into a Barr body. They have small testes and are sterile but otherwise appear female.
d.
A mutation or deletion of the SRY gene on the Y chromosome prevented development of testes and production of the male sex hormones required for a male phenotype.
e.
A translocation of part of an X chromosome to the Y chromosome resulted in a double dose of female-determining genes.
 

 18. 
A mutation in the mitochondrial gene has been linked to a rare muscle-wasting disease in humans. This disease is
a.
found more often in males than in females
b.
found more often in females than males
c.
inherited in a simple Mendelian fashion
d.
caused by a translocation of a nuclear gene to the mitochondria
e.
inherited from the mother and is equally likely to occur in male offspring as in female offspring
 

 19. 
The genetic event that results in Turner syndrome (XO) is probably
a.
nondisjunction
b.
deletion
c.
genomic imprinting
d.
monoploidy
e.
independent assortment
 

 20. 
A cross between a wild-type mouse and a dwarf mouse homozygous for a recessive mutation in the Igf2 gene produces heterozygous offspring that are normal size if the dwarf parent was the mother, but dwarf if the dwarf parent was father. Which of the following genetic events explains these results?
a.
sex-linked inheritance
b.
monosomy
c.
genomic imprinting
d.
inheritance of mitochondrial genes
e.
a mutant XIST allele
 



 
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