Download genetics exam 2 2002

General Genetics Exam 2
Name ___________________________
Multiple Choice (Choose the one best answer) (2 pt.)
1. ___ Typical ratios resulting from epistatic interactions in dihybrid crosses would be __.
a)
b)
c)
d)
e)
9:3:3:1, 1:2:1
1:1:1:1, 1:4:6:4:1
9:3:4, 9:7
1:2:2:4:1:2:1:2:1
3:1, 1:1
2. ___ An experiment to determine the inheritance of pod length in soybean crossed two
plants with intermediate length pods. The following progeny were recovered from the
cross. 52 plants had long pods, 110 had intermediate length pods and 48 had short pods.
What is your hypothesis for how pod length is inherited in soybean?
a)
b)
c)
d)
complete dominance
incomplete dominance
epistasis
low penetrance
3. ___ An allele that reverses the effect of a mutation of another gene, resulting in a wildtype phenotype is a(n)
a)
b)
c)
d)
activator
repressor
suppressor
dominator
4. ___ The purpose for check points in the cell cycle is to
a)
b)
c)
d)
e)
cause cells to grow out of control leading to cancers
stop mitosis to prevent chromosome duplication
stop DNA synthesis to prevent chromosome duplication
pause the cell cycle until all the necessary building blocks are synthesized
give geneticists something else to study
5. ___ The three subdivisions of interphase are
a)
b)
c)
d)
G1, S and G2
prophase, metaphase and anaphase
M phase, mitosis and cytokinesis
pollination, fertilization and meiosis
6. ___ During interphase of the cell cycle ___.
a)
b)
c)
d)
DNA recombines
Sister chromatics move to opposite poles
The nuclear membrane disappears
DNA content essentially doubles
7. ___ In a complementation test the number of complementation groups indicates
a)
b)
c)
d)
the number of genes required for a specific phenotype
the penetrance of phenotype
the number of alleles for a gene
the number of chromosomes in an organism
8. ____ The percentage of individuals with a given genotype who exhibit the phenotype
associated with that genotype is called
a)
b)
c)
d)
penetrance
expressivity
incomplete dominance
co-dominance
9. ___ ____ result from chromosome replication and are joined together at a protein
structure called a centromere.
a)
b)
c)
d)
e)
homologous chromosomes
heterologous chromosomes
complementary chromosomes
sister chromatids
parallel chromatids
10. ___ The orderly sequence of events which occurs in the cell from one cell division to
the next is called
a)
b)
c)
d)
mitosis
interphase
the cell cycle
recombination
11. ___ A situation in which an allele causes inviability when present in two doses is called
a)
b)
c)
d)
e)
penetrance
expressivity
incomplete dominance
co-dominance
lethality
12. ___ During G1 of interphase
a) chromosomes condense, the mitotic spindle forms and the nuclear
envelope and nucleolus disappear
b) DNA synthesis occurs (chromosomes double)
c) Synthesis of proteins for cell division and general preparation for cell
division by the cell.
d) protein production increases, an increased number of organelles are made
and the cell grows in size.
13. ___ During which phase of mitosis does the nuclear envelope re-form, nucleoli
reappear and chromosomes de-condense?
a)
b)
c)
d)
prophase
metaphase
anaphase
telophase
14. ___ During anaphase of mitosis
a)
b)
c)
d)
e)
DNA recombines
Sister chromatids move to opposite poles
The nuclear membrane disappears
RNA replicates
DNA content essentially doubles
15. ___ A person who has type A blood has
a)
b)
c)
d)
A antigens on the cell surface
B antigens on the cell surface
both A and B antigens on the cell surface
no surface antigens
16. ___ The end result of meiosis is
a)
b)
c)
d)
two cells with the exact same chromosome complement of the starting cell
two cells with half the chromosome complement of the starting cell
four cells with the exact same chromosome complement of the starting cell
four cells with half the chromosome complement of the starting cell
17. ___ The phase during which homologous chromosomes pair up to form a tetrad and
crossing over occurs between homologous chromosomes is
a)
b)
c)
d)
prophase I of mitosis
prophase II or mitosis
prophase I of meiosis
prophase II or meiosis
18. ___ In rabbits, when a pure-breeding black is crossed with a pure-breeding white the
F1 are all black. However, the F2 shows 9 black, 1 white and 6 of a new color, silver. The
silver phenotype is most likely determined by
a)
b)
c)
d)
complementary alleles of two different genes.
a heterozygote of the alleles that determine black and white
passive epistasis
the presence of a dominant allele at either of the two loci and black is
determined by the presence of the dominant allele at both loci.
Fill in the blank (1 pt each)
Label the phases below (note, the diagrams are not necessarily in order)
In the diagram below, which box properly illustrates the arrangement of chromosomes
(2n = 4) during:
Metaphase of mitosis
______
Metaphase I of meiosis
______
Metaphase II of meiosis
______
Short answer (variable)
The recessive allele of an X-linked gene in fruit flies results in a yellow body color
compared to the normal (wild-type) brown body color. Using punnet squares, diagram a
cross between a true-breeding, normal bodied female and a yellow-bodied male and the
reciprocal cross between a yellow-bodied female and a normal-bodied male. What are
the phenotypes of the F1 generation from both crosses? (4 pts)
A phenotypically normal couple have a normal daughter and a son with X-linked
hemophilia. What are the genotypes of the parents? What is the probability that the
daughter is heterozygous? (2 pts)
A laboratory investigating a metabolic pathway in nematodes isolated 9 mutant strains.
The results of complementation analysis of the 9 mutants strains is illustrated below in
which a plus sign indicates complementation of the mutant phenotype. Based on these
results, how many genes appear to be involved in the metabolic pathway? Which
mutants are in each complementation group? (4 pts)
1 2 3
1 - - +
2
- +
3
4
5
6
7
8
9
4
+
+
+
-
5
+
+
+
-
6
+
+
+
+
-
7
+
+
+
+
-
8
+
+
+
+
+
+
+
-
9
+
+
+
+
+
+
-
Mating of two ferrocious jackalopes produces 54 ferrocious and
10 docile offspring. Does this fit a model of docile being a
recessive allele of a single gene if the parents are heterozygous?
Show your work. (3 pts)
Four varieties of squirrel have been studied with four different colors of fur (brown, gray,
black and white). Investigators believe that two genes are involved in determining fur
color. A series of crosses between dihybrid varieties produced offspring in the following
ratio: 98 black: 26 gray: 22 brown: 14 white. Does the data support the hypothesis that
fur color in squirrels is due to the interaction between 2 genes? (Show your work) (4 pts)