Bio Chapter 12: Questions

Question 1

What property distinguished Mendel’s investigation from
previous studies?
a. Mendel used true-breeding pea plants.
b. Mendel quantified his results.
c. Mendel examined many different traits.
d. Mendel examined the segregation of traits

Answer 1

Mendel quantified his results.

Question 2

Mendel crossed tall pea plants and dwarf pea plants to produce
an F1 that is all tall. If this F1 were crossed back to the dwarf
parent, what would be the outcome?
a. 3 tall:1 dwarf
c. 1 dwarf:1 tall
b. 3 dwarf:1 tall
d. All tall

Answer 2

c. 1 dwarf:1 tall

Question 3

The F1 generation of the monohybrid cross purple (PP) ×
white (pp) flower pea plants should
a. all have white flowers.
b. all have a light purple or blended appearance.
c. all have purple flowers.
d. have ¾ purple flowers and ¼ white flowers.

Answer 3

all have purple flowers.

Question 4

Which of these is NOT a part of Mendel’s five-element
model?
a. Traits have alternative forms (what we now call alleles).
b. Parents transmit discrete traits to their offspring.
c. If an allele is present, it will be expressed.
d. Traits do not blend.

Answer 4

If an allele is present, it will be expressed.

Question 5

An organism’s is/are determined by its .
a. genotype; phenotype
c. alleles; phenotype
b. phenotype; genotype
d. genes; alleles

Answer 5

phenotype; genotype

Question 6

In all of Mendel’s monohybrid crosses, the F2 plants displayed
a 3:1 ratio of dominant to recessive traits. Of those showing
the dominant trait, what proportion were true-breeding?
a. ¼ c. ⅔
b. ⅓ d. None

Answer 6

2/3

Question 7

. In a simple monohybrid cross, if true-breeding tall plants are
crossed with true-breeding plants of normal height, and the F1
plants (all tall) are allowed to self-pollinate, what fraction of
the F2 generation are both tall and homozygous?
a. ½ c. None
b. ¼ d. 1/16

Answer 7

1/4

Question 8

What is the probability of obtaining an individual with the
genotype bb from a cross between two individuals with the
genotype Bb?
a. ½ c. ⅛
b. ¼ d. 0

Answer 8

1/4

Question 9

A dihybrid cross between a plant with long, smooth leaves and
a plant with short, hairy leaves produces a long, smooth F1. If
this F1 is allowed to self-cross to produce an F2, what would
you predict for the ratio of F2 phenotypes?
a. 9 long, smooth:3 long, hairy:3 short, hairy:1 short, smooth
b. 9 long, smooth:3 long, hairy:3 short, smooth:1 short, hairy
c. 9 short, hairy:3 long, hairy:3 short, smooth:1 long, smooth
d. 1 long, smooth:1 long, hairy:1 short, smooth:1 short, hairy

Answer 9

9 long, smooth:3 long, hairy:3 short, smooth:1 short, hair

Question 10

Which is most important in explaining the idea behind
Mendel’s principle of independent assortment?
a. Meiosis I
b. Meiosis II
c. Mitosis
d. Both a and b are equally important

Answer 10

Meiosis I

Question 11

Consider a long, smooth F2 from the previous question. This
plant’s genotype
a. must be homozygous for both leaf texture and leaf length alleles.
b. must be heterozygous for both leaf texture and leaf
length alleles.
c. must be homozygous for one allele and heterozygous for
the other allele.
d. could be homozygous or heterozygous for both leaf texture
and leaf length alleles.

Answer 11

could be homozygous or heterozygous for both leaf texture
and leaf length alleles.

Question 12

In a hypothetical animal, brown eyes (B) are dominant to pink
eyes (b), and a solid coat (S) is dominant to a spotted coat (s).
An animal with brown eyes and a solid coat produces which of
the following types of gametes?
a. B, b, S, s c. BS, Bs, bS, bs
b. Bb, Ss d. Bb, BB, SS, Ss

Answer 12

BS, Bs, bS, bs

Question 13

Of the following crosses, which is a test cross?
a. WW × WW
c. Ww × ww
b. WW × Ww d. Ww × W

Answer 13

Ww × ww

Question 14

A dihybrid cross between an animal with brown fur and
two toes and an animal with white fur and three toes is
allowed to proceed to the F2 generation, where you see
9 brown two toes:3 brown three toes:3 white two toes:1
white three toes. Given this information, which of the
following is true?
a. Brown fur is dominant to white fur; two toes is dominant
to three toes.
b. White fur is dominant to brown fur; three toes is dominant
to two toes.
c. Brown fur is dominant to two toes; white fur is dominant
to three toes.
d. You can’t determine which allele is dominant or recessive
based on the information given

Answer 14

You can’t determine which allele is dominant or recessive
based on the information given

Question 15

To predict the outcome of independent events, it is
useful to
a. use the product rule.
b. use rule of addition.
c. use the law of segregation.
d. use a testcross.

Answer 15

use the product rule.

Question 16

Which statement about a testcross is true?
a. If the test individual is homozygous, the progeny will
exhibit a 3:1 ratio.
b. If the test individual is heterozygous, the progeny will
exhibit a 3:1 ratio.
c. If the test individual is homozygous, all the progeny will
appear dominant.
d. If the test individual is heterozygous, all the progeny will
appear dominant.

Answer 16

If the test individual is homozygous, all the progeny will
appear dominant.

Question 17

In beagles, glaucoma is inherited as an autosomal recessive
trait. You breed two beagles that are heterozygous for
glaucoma. What is the probability that both of their first two
pups will have glaucoma?
a. ¼ c. ⅟16
b. ¾ d. ½

Answer 17

⅟16

Question 18

Cystic fibrosis (CF) is a human condition caused by a defect
in the cystic fibrosis transmembrane regulator protein (CFTR).
Cystic fibrosis is inherited in an autosomal recessive manner.
Which is true about CF?
a. Heterozygous individuals will have CF.
b. Heterozygous individuals make enough normal CFTR for
normal cellular function.
c. An individual who carries the defective allele will have
children with CF.
d. None of the above

Answer 18

Heterozygous individuals make enough normal CFTR for
normal cellular function

Question 19

Changing one nucleotide in a gene changes the
amino acid sequence of the protein and changes the
function of the protein.
a. always; always
b. always; sometimes
c. sometimes; always
d. sometimes; sometime

Answer 19

sometimes; sometime

Question 20

Albinism is an autosomal recessive condition that results in little
or no color (pigment) in the skin, hair, and eyes of vertebrates. It
is caused by a defect in the enzyme tyrosinase. A heat-sensitive
tyrosinase is found in Siamese cats. What is a reasonable
explanation for the fact that the head and torso of these animals,
where the body temperature is relatively high, is white?
a. The normal allele degrades at high body temperatures.
b. The enzyme denatures at high body temperatures.
c. The enzyme functions more quickly at the higher
temperatures.
d. Both b and c

Answer 20

Both b and c
b. The enzyme denatures at high body temperatures.
c. The enzyme functions more quickly at the higher
temperatures.

Question 21

Phenotypes such as height in humans, which show a
continuous distribution, are usually the result of
a. an alteration of dominance for multiple alleles of a
single gene.
b. the presence of multiple alleles for a single gene.
c. the action of one gene on multiple phenotypes.
d. the action of multiple genes on a single phenotype

Answer 21

the action of multiple genes on a single phenotype

Question 22

In epistasis,
a. a portion of a chromosome is deleted.
b. one gene masks the effect of another.
c. only recessive traits are expressed.
d. the behavior of linked genes is independent

Answer 22

one gene masks the effect of another.

Question 23

The ABO blood group in humans is determined by multiple
alleles. I
A and I
B are codominant and are both dominant over I
O.
Consider a case in which a mother is type O and her newborn
infant is type A. The possible phenotypes of the father are
a. A, B, or AB. c. O only.
b. A or AB. d. A or O

Answer 23

A or AB

Question 24

You discover a new variety of plant with color varieties of
purple and white. When you intercross these, the F1 is a lighter
purple. You consider that this may be an example of blending
and self-cross the F1. If Mendel is correct, what would you
predict for the F2?
a. 1 purple:2 white:1 light purple
b. 1 white:2 purple:1 light purple
c. 1 purple:2 light purple:1 white
d. 1 light purple:2 purple:1 white

Answer 24

. 1 purple:2 light purple:1 white