Exam 2 Fall 17

Question 1

True or False:

Mitosis takes place in your gametes, whereas meiosis takes place in your somatic cells.

Answer 1

F

Question 2

True or False:

An X chromosome is an autosome.

Answer 2

F

Question 3

True or False:

Alleles are described as alternate versions of a gene.

Answer 3

T

Question 4

True or False:

Sister chromatids are joined at the telomere.

Answer 4

f

Question 5

True or False:

Differentiation of the zygote into a multicellular organism results from selective gene expression.

Answer 5

t

Question 6

True or False:

Skin cells contain information about skin color but not about muscle proteins

Answer 6

f

Question 7

True or False:

Mutations in DNA can lead to new alleles.

Answer 7

t

Question 8

True or False:

The process by which the genotype is expressed as phenotype is known as gene expression

Answer 8

t

Question 9

True or False:

The phenotype always shows the recessive allele.

Answer 9

f

Question 10

True or False:

Proto-oncogenes are normal genes with the potential to become oncogenes.

Answer 10

t

Question 11

An example of nondisjunction is when:
A) homologous chromosomes fail to separate during meiosis
B) DNA fails to replicate before meiosis
C) a cell does not go through cytokinesis
D) meiosis stops after the first cell division

Answer 11

a

Question 12

A woman with type A blood has a child with type O blood. What is the woman’s genotype?
A. IBi
B. IAi
C. Ii
D. IAIA 
E. IAIB

Answer 12

b

Question 13

Mature human nerve cells and muscle cells

A. become cancerous more easily than other cell types.
B. continue to divide throughout their lifetime.
C. are permanently in a state of nondivision.
D. cease dividing after a predetermined number of cell generations.

Answer 13

c

Question 14

Which of the following shows the greatest promise as a cancer chemotherapy agent?

A. a drug that interferes with cellular respiration
B. a drug that prevents mitotic spindle from forming
C. a drug that prevents crossing over
D. a drug that prevents tetrad formation

Answer 14

b

Question 15

Meiosis results in 2^n possible chromosomal combinations in humans. How many chromosomal combinations are possible for gametes formed by meiosis in humans?

a) 46
b) 2,116
c) 46,604
d) 8,388,608

Answer 15

d

Question 16

Cystic fibrosis in humans is caused by mutations in a single gene and is inherited as an autosomal (non-sex-chromosome) recessive trait. A normal couple has two children. The first child has cystic fibrosis, and the second child is unaffected. What is the probability that the second child is a carrier (heterozygous) for the mutation that causes the disease?

A. 1/4 or 25%
B. 1/2 or 50%
C. 2/3 or 67% 
D. 3/4 or 75% 
E. 1 or 100%

Answer 16

c

Question 17

Cancer is not usually inherited because

A. The chromosomal changes in cancer are usually confined to somatic cells
B. The causes of cancer are not usually genetic
C. People with cancer usually die before reproducing
D. The cancerous cells usually interfere with the ability to produce gametes

Answer 17

a

Question 18

How many sex chromosomes are in a human gamete? 
A. One 
B. two
C. three
D. Four

Answer 18

a

Question 19

The term “gene expression” refers to the

A. fact that each individual of a species has a unique set of genes.
B. fact that individuals of the same species have different phenotypes.
C. process by which genetic information flows from genes to proteins.
D. flow of information from parent to offspring.

Answer 19

c

Question 20

How is it that the cells in different body tissues are able to perform different functions?

A. The cells contain different genes.
B. The cells exhibit different patterns of gene expression.
C. Different chromosomes have been inactivated in different cells.
D. The mutations that have accumulated in the cells of the different tissues control functions.

Answer 20

b

Question 21

How is it that the cells in different body tissues are able to perform different functions?

A. The cells contain different genes.
B. The cells exhibit different patterns of gene expression.
C. Different chromosomes have been inactivated in different cells.
D. The mutations that have accumulated in the cells of the different tissues control functions.

Answer 21

b

Question 22

Genetic variation is accomplished by all but one of the following. Which is it? 
A. the events of meiosis I
B. crossing over
C. independent assortment
D. the events of meiosis II

Answer 22

d

Question 23

The individual features of all organisms are the result of A. Genetics
B. The environment
C. The environment and individual needs
D. The environment and genetics

Answer 23

d

Question 24

One difference between mitosis and meiosis is ______.

A. mitosis produces cells genetically identical to the parent cell, but meiosis does not
B. mitosis produces haploid cells, but meiosis produces diploid cells
C. mitosis produces more daughter cells than meiosis
D. mitosis requires only one parent cell, but meiosis requires two parent cells

Answer 24

a

Question 25

What chromosomes belong to a normal human female? A. 22 autosomes and 2 X chromosomes B. 44 autosomes and 2 X chromosomes C. 44 autosomes, one X chromosome, and one Y D. chromosome 46 autosomes and two X chromosomes

Answer 25

b

Question 26

Justin has type A blood and his wife Brittany has type B blood. Justin's parents both have type AB blood, and Brittany's parents also both have type AB blood. What are the chances that Justin and Brittany's son Theodore has type A blood? a) 100% b) 75% c) 25% d) 0%

Answer 26

d

Question 27

``` Mitosis is necessary for all of the following EXCEPT: A) growth B) replacing worn-out cells C) repair of wounds D) production of gametes ```

Answer 27

d

Question 28

If crossing over has taken place, A) the chromosomes involved will each be a mix of maternal and paternal DNA B) the individual must be homozygous C) the chromosomes involved will end up in the same gamete D) the cells that are formed will be genetically identical

Answer 28

a

Question 29

Hemophilia is an X-linked recessive condition. A man with hemophilia (XhY) and a woman who does not carry a copy of the allele that causes hemophilia (XHXH) have a son. What is the probability that he will have hemophilia? A) 0% B) 25% C) 50% D) 100%

Answer 29

a

Question 30

``` Life cycles for eukaryotes move between a diploid and haploid phase. At some point during the diploid phase, some cells of the organism undergo: A) fertilization B) meiosis C) mitosis D) A & B E) B & C ```

Answer 30

e

Question 31

``` The phenotype of an organism is ___. A) its genetic makeup B) its physical characteristics C) a hypothesis of its evolutionary origins D) both A and B ```

Answer 31

b

Question 32

Two plants with a heterozygous genotype (Aa) are crossed. What proportion of their offspring are expected to have a heterozygous genotype (Aa)? A) all of the offspring will be heterozygous B) 3⁄4 C) 1⁄2 D) 1⁄4 E) none of the offspring will be heterozygous

Answer 32

c

Question 33

Which of the following occurs during prophase I of meiosis? A) homologous pairs of chromosomes align in the center of the cell B) homologous chromosomes pair up C) homologous chromosomes are separated D) sister chromatids are separated

Answer 33

b

Question 34

``` The role of spindle microtubules is to: A) replicate DNA B) condense chromosomes C) repair DNA D) move and separate chromosomes ```

Answer 34

d

Question 35

``` Crossing over takes place during: A) mitosis B) meiosis C) cytokinesis D) both A and B ```

Answer 35

b

Question 36

``` Mendel crossed a plant grown from a yellow seed with a plant grown from a green seed. The offspring consisted of all yellow seeds. This demonstrated that: A) yellow is the dominant phenotype B) yellow is the recessive phenotype C) yellow and green are codominant D) none of the above ```

Answer 36

a

Question 37

Duchenne Muscular Dystrophy (DMD) is an X-linked recessive trait that causes muscular weakness. The allele for DMD is represented by Xd and the normal allele is represented by XD. Neither parent has DMD, but both of their sons express the trait. What are the genotypes of the parents? A XDXD and XdY B XDXD and XDY C XDXd and XdY D XDXd and XDY

Answer 37

d

Question 38

Male-pattern baldness is an X-linked recessive trait (Xb) with the dominant normal hair gene being XB. A father with the genotype XBY and a mother with the genotype XbXb have a son. What is the percent chance that the son will inherit male-pattern baldness? ``` A 50% B 75% C 0% D 100% E 25% ```

Answer 38

d

Question 39

Color blindness is a sex‑linked trait in humans. A woman who is a carrier for color blindness has children with a man who is color blind. Which of the following is true regarding their offspring? A No daughters are color blind B All sons are carriers C All sons are color blind D Any daughter is either color blind or a carrier

Answer 39

d

Question 40

In Drosophila flies, eye color is sex-linked. The allele for red eyes XW is dominant to the allele for white eyes Xw. A male fly with red eyes XWY and a carrier female XWXw are mated. Part 1: What is the probability that the female offspring will have white eyes? ``` A 50% B 75% C 0% D 100% E 25% ```

Answer 40

c