Test 2

Question 1

What do tumor suppressor proteins do to cell division?

Answer 1

They inhibit it

Question 2

Cell division, which is the climax of the cell cycle, consists of

Answer 2

cytokineses plus mitosis or meiosis

Question 3

The G0 phase of the cell cycle is distinguished by

Answer 3

the absence of preparation for DNA synthesis Correct

Question 4

The mitotic spindle is made of

Answer 4

microtubules

Question 5

You are examining the rapidly dividing cells of a fish embryo and notice a cell that seems to contain two nuclei with complete nuclear envelopes and decondensing chromosomes. The middle of the cell is pinched inward. This cell must be in

Answer 5

telophase

Question 6

After a single cell undergoes meiosis in a male, how many sperm cells will be produced?

Answer 6

4

Question 7

The distribution of DNA into homologous pairs of chromosomes allows

Answer 7

cells to reduce their number of chromosomes by half during meiosis Correct

Question 8

Normal cell division requires what kind of proto-oncogenes and what kind of tumor suppressor genes.

Answer 8

activated proto oncogenes and inactivated tumor suppressor genes

Question 9

If exposure to sunlight causes a mutation in a single proto-oncogene in a diploid cell so that it becomes hyperactive, then

Answer 9

the cell might produce a protein that pushes it into rapid cell division

Question 10

cancer in humans is caused by

Answer 10

both environmental and genetic factors

Question 11

an allele is

Answer 11

a version of a gene

Question 12

If a person has one copy of each of two different alleles for a given gene, the person is ________ for that trait.

Answer 12

heterozygous

Question 13

Which of the following symbols correctly represents a person who has a homozygous genotype?

Answer 13

WW

Question 14

Mendel’s laws were able to accurately predict the pattern of inheritance for situations in which

Answer 14

one allele completely makes another allele

Question 15

Each time a person has another child, the chance that the parent passes on a given allele to a child

Answer 15

is the same

Question 16

A Punnett square is used to

Answer 16

to predict the outcome of a genetic cross

Question 17

An plant with the genotype Aa mates with a plant with the genotype AA. Which of the following is true?

Answer 17

half of the offspring will be Aa

Question 18

Two parents have ABO blood group genotypes of IAi and IAIB. Which of the following blood types could NOT belong to one of their children?

Answer 18

O

Question 19

One of the first medical tests a newborn receives determines if the child has phenylketonuria (PKU). PKU is the result of a mutation in a single gene that causes mental retardation and a host of other phenotypes (light hair and skin color, eczema, and a “mousy” smell). By detecting PKU early, doctors are able to reduce the effect of this condition with a modified diet. PKU is an example of

Answer 19

pleiotropy

Question 20

Two genes control fur color in Labrador retrievers. The first gene determines whether the pigment to be deposited in the hair will be black or brown. The second gene determines whether the pigments are put into the dog’s hair at all. A dog homozygous for the recessive allele of this second gene will be yellow because no pigment is deposited in its fur. This is an example of

Answer 20

epistatsis

Question 21

Chromosomes that are NOT involved in determining gender are known as

Answer 21

autosomes

Question 22

How do genes on autosomes play a role in sex determination?

Answer 22

The SRY gene product has an effect on autosomal genes Correct

Question 23

Inheritance is said to be both stable and variable because

Answer 23

most of the time, genetic material is transferred with complete accuracy to the next generation while still creating unique individuals

Question 24

Which of the following statements about crossing-over is true?

Answer 24

It disrupts the linkage between genes

Question 25

Genes that are located on opposite ends of the same chromosome are

Answer 25

affected by crossing-over so frequently that they may appear to undergo independent assortment

Question 26

Which of the following genetic changes would NOT be heritable?

Answer 26

a mutation in a skin cell

Question 27

An allele that appears to “skip generations” is most likely=

Answer 27

recessive

Question 28

Most inherited human disorders are the result of

Answer 28

recessive mutations of genes located on autosomes

Question 29

A man is a carrier for a recessive disease allele. A woman is not a carrier and does not have the disease. The couple has four children and

Answer 29

none of the children have the disease

Question 30

Even though it is deadly, the Huntington disease allele can remain in the population, because

Answer 30

people with the disorder often live long enough to reproduce

Question 31

A woman who is a carrier for a recessive X-linked disorder has children with a man who does not have the disease. Which of the following is true of the couple’s children?

Answer 31

Their sons have a 50 percent chance of having the disorder

Question 32

During cell division, a piece of a chromosome breaks away and is added to the end of its homologue. The homologue with the addition is an example of

Answer 32

duplication

Question 33

An XX individual develops as a male. Which of the following statements offers the most likely explanation?

Answer 33

A piece of a Y chromosome has become attached to one of the X chromosomes

Question 34

The tendency to develop diseases, such as cancer and heart disease, is

Answer 34

the result of the interaction of multiple genes and environmental factors

Question 35

Which of the following would NOT be a required biological property of genetic material?

Answer 35

It must exist in paired copies

Question 36

All cells in an organism contain a full copy of that organism’s DNA. Your ears do NOT produce digestive enzymes because

Answer 36

different genes are expressed in different parts of an organism

Question 37

Estrogen is a hormone that binds to a receptor on the surface of some cells. This binding causes regulatory molecules in the nucleus to interact with a segment of DNA that precedes some genes. This interaction activates the gene and causes gene expression. The segment of DNA that the regulatory molecules bind to is called

Answer 37

promoter

Question 38

the hydrogen bonds in DNA hold together what?

Answer 38

The bases on one strand of DNA are held to the bases on the other strand

Question 39

What part of a nucleotide accounts for the genetic variation between individuals?

Answer 39

base

Question 40

Assume a certain molecule of DNA is composed of exactly 22 percent adenine. How much cytosine would you expect to find in this molecule?

Answer 40

28 percent

Question 41

To start DNA replication, the bonds holding the strands together are broken, and the molecule begins to unwind. Which of the following statements best summarizes what happens next?

Answer 41

Each old strand acts as a template for a new strand

Question 42

A rapidly dividing cell is exposed to a chemical that converts the bond that forms between adenine and thymine to a covalent bond. Which of the following is most likely to occur?

Answer 42

DNA replication would not occur because the two nucleotide strands that make up the DNA molecule would not be able to separate

Question 43

Benzopyrene is a compound found in cigarettes that binds to the base guanine in DNA. This distorts the DNA double helix and causes changes in DNA sequence. Based on this information, benzopyrene is a

Answer 43

mutagen

Question 44

A mistake during which of the following processes would have the most long-lasting effects on an organism and its offspring?

Answer 44

a replication in germline cells

Question 45

Which of the following must occur for a mismatch error to be repaired?

Answer 45

DNA repair proteins identify damaged DNA

Question 46

Most eukaryotic DNA is

Answer 46

noncoding

Question 47

A segment of DNA is present in a gene, is transcribed, but is not used in translation. This segment of DNA is a(an)

Answer 47

intron

Question 48

If their food source changes from lactose to arabinose, bacteria turn off their genes for lactose enzymes and turn on their genes for arabinose enzymes. Why don’t bacteria express the genes for both lactose and arabinose enzymes all the time?

Answer 48

To prevent the waste of energy and resources on unneeded protein production

Question 49

The enzymes involved in ATP synthesis in the mitochondria are likely to be encoded by ________ genes

Answer 49

housekeeping

Question 50

Which of the following might lead to a genome copy number variant in which the individual has only one copy of a gene instead of the normal two copies?

Answer 50

chromosomal deletion

Question 51

Prokaryotes lack membrane-bound organelles and thus do not have nuclei; therefore

Answer 51

prokaryotic transcription and translation both take place in the cytoplasm

Question 52

Which of the following does NOT take place in the nucleus?

Answer 52

translation

Question 53

The key enzyme used during transcription is

Answer 53

RNA Polymerase

Question 54

During RNA splicing

Answer 54

introns are removed from RNA, and the remaining exons are connected to form a mature mRNA

Question 55

Which of the following is NOT a feature of the genetic code?

Answer 55

Every individual has a different genetic code

Question 56

Which molecules are involved in translation?

Answer 56

mRNA, tRNA, and rRNA

Question 57

If a particular segment of DNA has the base sequence TAC, what will be the base sequence of the anticodon of the tRNA that carries the amino acid encoded by that stretch of DNA?

Answer 57

UAC

Question 58

It is possible for a mutation to occur and yet not alter the end product of translation if

Answer 58

the new codon encodes the same amino acid

Question 59

When one base is inserted in the DNA sequence of a gene, the result is a(n) ________ mutation

Answer 59

frameshift