Quiz2 Answers - biology tech support page

Biology 2107
Spring, 2015
Quiz #2
Name: __________________________
Student ID #: ____________________
Please circle the letters that precede the most appropriate answer(s) to the question asked. Be
aware, there is only one answer to each question, if there are more than one plausible
answers, choose the one that is most specific.
1.
What is meant by a “test cross”
A
B
C
D
The cross fertilization of an ovum with a spermatozoa
A cross that checks whether or not individuals from two different species are compatible.
A cross that checks whether or not individuals from the same species are compatible.
A cross between a true-breeding strain for a particular trait under scrutiny and an
“unknown” wild-type for the given trait.
A cross between an individual with an “unknown” genotype and another individual that is
a homozygous recessive for the particular trait under scrutiny
E
2.
Assuming that the height of a pea plant is determined by a single gene at a single
locus, when crossing a tall pea plant (Tt ) with a dwarf pea plant (tt) which of the
following statements would be true
A
B
C
D
E
F
All the F1 generation would be heterozygous tall
All the F1 generation would be homozygous small
Half of the F1 generation would be homozygous small
Half of the F1 generation would be homozygous tall
If all the F1 generation were to be “selfed” 1/4 of the offspring would be homozygous
small
If all the F1 generation were to be “selfed” all the offspring would be heterozygous tall
3.
Mendel’s 2nd law states that:
A
During gamete formation the segregation of one gene pair is independent of all other
gene pairs
Two members of a gene pair segregate from each other into the gametes, whereby one
half of the gametes carries one of the traits, the other half carries the other
The union of one gamete from each parent to form a resultant zygote is random with
respect to that particular characteristic.
Like all things biological, genes come in pairs.
When fertilization occurs, the zygote gets one half of its chromosomal set from each
parent, thus restoring the pair.
B
C
D
E
4.
In which specific phase of the cell cycle of a germ-line cell is the “programming”or
“instruction” for new DNA synthesis initiated.
A
B
C
D
E
F
S-phase
Gap phase 1
Interphase
Prophase I
Prophase II
Gap phase 2
5.
Which one of the following examples from the lecture series would best fit into the
category of “multiple alleles”.
A
B
C
D
E
F
Hair colour in horses
M and N blood groups
Shape of the “purse” in Shepherd’s purse
ABO blood groups
Height in humans
Petal colour in carnations
6.
A mother of four (2 girls and 2 boys) exhibits a recessive X-linked trait. Assuming
that she married a man who did not, what is the most likely outcome in their offspring
(according to the laws of probability).
A
B
C
D
E
F
All the offspring exhibit the trait.
Both boys would appear to be wild-type.
None of the girls would exhibit the trait
None of the offspring would exhibit the trait.
One of the girls would be a carrier, while the other would exhibit the trait.
One of the boys would exhibit the trait, while the other would not.
7.
A trait is said to be “pleiotropic” when.
A
B
C
D
E
F.
It defines a phenotype that is highly variable
It has more than three loci
It s found in two different species
It gives rise to more than one phenotype
It masks the expression of other genes
It defines a phenotype that s ambivalent, neither one thing nor another
8.
What is the probability that an individual is Aa or AA for an autosomal gene, as a
result of a cross between parents that are heterozygous for the trait?.
A
B
C
D
E
F.
¼
½
¾
1
cannot be determined without knowing that what the father is
cannot be determined without knowing that what the mother is
9.
Take a look at the following figure and, using the information given as well as your
knowledge of the course thus far, give the most straight forward answer to the two
questions by circling the most appropriate answer. (2pts for each part of the answers in
this question).
(a)
The cell being observed is in:
A
B
C
D
E
F
Prophase I
Anaphase II
Metaphase
Metaphase II
Anaphase I
Telophase I A
(b)
This cell is:
A
B
C
D
E
A “germ-line” cell
A “recombinant” cell
A “somatic” cell
A “cancerous” cell
There is insufficient
information to choose
In the next four questions please circle your evaluation of the statement given. Be
Careful !
3pts.
10.
“Multiple genes” rarely, if ever, give rise to Mendelian-type distribution of their phenotype.
True
11.
If present the genotype of a dominant allele will always show through.
True
12.
False
Epistasis is the interaction between two or more genes such that expression of one gene
masks the phenotypic expression of the other(s).
True
15.
False
Almost by definition, all of the traits that Mendel analyzed in his dihybrid crosses were
derived from genes that were located on different chromosomes.
True
14.
False
The environment sometimes plays a role in determining the phenotype for a given trait
True
13.
False
False
Sex-linked traits always refer to genes located on the X-chromosome.
True
False