exam three

Question 1

All viruses have _____.
a capsid (protein coat)
a viral genome
mitochondria
two of the above
all of the above

Answer 1

two of the above

Question 2

The Ames test ______
a. provides a way to determine if any type of cell has experienced a mutation.
b. provides a way to determine if an agent is a mutagen.
c. allows researchers to experimentally disrupt gene activity by causing a mutation in a specific gene.
d. provides a way to repair mutations in bacterial cells.
e. does all of the above.

Answer 2

b. provides a way to determine if an agent is a mutagen.

Question 3

A replicated chromosome is composed of

Answer 3

two sister chromatids held together at the centromere.

Question 4

Cell differentiation is driven by _____.

Answer 4

differential gene expression

Question 5

Which of the following can have an epigenetic effect on gene expression?
chromatin remodeling
covalent histone modification
localization of histone variants
DNA methylation
All of the above can have an epigenetic effect on gene expression.

Answer 5

All of the above can have an epigenetic effect on gene expression.

Question 6

Experimental advantages of using pea plants included which of the following?
They came in several varieties.
They were capable of self-fertilization.
They were easy to cross.
Their anthers could be removed prior to pollination.
All of the above are advantages.

Answer 6

All of the above are advantages.

Question 7

______ mutations lead to the entire organism carrying the mutations and can be passed on to offspring

Answer 7

Germ-line

Question 8

____ may be the result of nondisjunction during meiosis.

Answer 8

Aneuploidy

Question 9

A mutation in a single gene can have ____ on an individual’s phenotype.

Answer 9

multiple

Question 10

Bacterial fertility plasmids (F factors) can be transferred from donor strains to recipient strains through ___.

Answer 10

conjunction

Question 11

The Ras gene, which encodes an intracellular signaling protein, is an example of ____.

Answer 11

oncogenes

Question 12

Which of the following represents homozygous dominant genotype?
HH
Hh
hh

Answer 12

HH

Question 13

Which of the following DNA mutations can be repaired by the Nucleotide Excision Repair (NER) system?
UV-induced damage, such as thymine dimers.
chemically modified nucleotide bases
chromosomal translocations
two of the above
all of the above

Answer 13

two of the above

Question 14

Human beings are diploid organisms. A normal human somatic cell has ___ chromosomes.

Answer 14

two sets of chromosomes, a total of 46 chromosomes

Question 15

_________ can cause induced DNA mutations.
Benzo(a)pyrene, a chemical found in cigarette smoke,
UV (ultraviolet) light
Errors in DNA replication
Two of the above
All of the above

Answer 15

two of the above

Question 16

Human cancer development is a long process of accumulating genetic alterations, ultimately resulting in malignancy. This statement is ___.

Answer 16

true

Question 17

DNA mutations are ______ events

Answer 17

random

Question 18

The COVID-19 viral genome is ____.

Answer 18

ssRNA

Question 19

The process whereby a cell’s morphology and function change is called ___.

Answer 19

differentiation

Question 20

Chromosomal synapsis and crossing-over occur during ____.

Answer 20

meiosis

Question 21

Which of the following would not be observed in a pedigree if a genetic disorder was inherited in a recessive manner?
Two unaffected parents have an affected offspring.
Two unaffected parents have an unaffected offspring.
Two affected parents have an unaffected offspring.
One affected and one unaffected parent have an unaffected offspring.
All of the above would be possible for a recessive disorder.

Answer 21

Two affected parents have an unaffected offspring.

Question 22

Which of the following gene mutations changes a single amino acid in a polypeptide?

Answer 22

missense mutation

Question 23

Morphogens are _____.

Answer 23

molecules that convey positional information and promote changes in development

Question 24

Checkpoints during the cell cycle are important because they

Answer 24

ensure the integrity of the cell’s DNA

Question 25

In Triple X syndrome (XXX, female), ___ X chromosome(s) is (are) inactivated as Barr bodies.

Answer 25

two

Question 26

Gene transfer in which a bacterial cell takes up bacterial DNA from the environment is called ___.

Answer 26

transformation

Question 27

During mitosis, some mitotic spindle microtubules attach to ____ of sister chromatids.

Answer 27

Kinetochores

Question 28

In terms of life cycle, many fungi and protists are _____.

Answer 28

haploid-dominant species

Question 29

According to Mendel’s Law of Segregation, every gamete receives ___ of a gene.

Answer 29

one allele

Question 30

A pea plant has the genotype TtRr. The independent assortment of these two genes occurs at ____ because chromosomes with the ____ alleles line up independently of those with the ____ alleles.

Answer 30

metaphase of meiosis I; T and t; R and r

Question 31

The P53 gene, which encodes a G1 checkpoint protein, is an example of ____.

Answer 31

tumor-suppressor genes

Question 32

Congenital analgesia is a recessive human trait. For a couple, each heterozygous for the recessive allele causing congenital analgesia, what is the probability that their first four offspring will have the disease?

Answer 32

1/256

Question 33

Genomic imprinting, such as imprinted Igf2 gene, _____ gene expression throughout the life of the individual.

Answer 33

inactivate or downregulate

Question 34

Viroids are composed solely of ___ and infect plant cells.

Answer 34

a single-stranded circular RNA

Question 35

Two hallmarks of stem cells are _____.

Answer 35

self-renewal and cell differentiation

Question 36

Which of the following is not a commonly used model organism in animal development?
Fruit fly
Mouse
Zebrafish
Nematode worm
None of the above

Answer 36

none of the above

Question 37

Three checkpoints in the eukaryotic cell cycle are ____.

Answer 37

G1 checkpoint, G2 checkpoint, and metaphase checkpoint

Question 38

The process of acquiring genes from another organism without being the offspring of that organism is known as ____.

Answer 38

horizontal gene transfer

Question 39

Genetic inheritance patterns include _____.

Answer 39

simple Mendelian inheritance
incomplete dominance
codominance
gene linkage

Question 40

Mutagens can cause mutations by ___.

Answer 40

chemically altering DNA nucleotides and disrupting DNA replication.

Question 41

HIV, a retrovirus, has a high mutation rate because ___.

Answer 41

reverse transcriptase lacks a proofreading function.

Question 42

The majority of organismal traits are ____.

Answer 42

quantitative, continuous variation over a range of phenotypes

Question 43

In biology, a series of changes in the state of a cell, tissue, organ, or organism is called ___.

Answer 43

development

Question 44

During viral infection, attachment is usually specific to a particular cell type because ___.

Answer 44

the virus recognizes and binds to specific molecules on the surface of the host cell.

Question 45

Which of the following can affect an individual’s traits?
action
gene mutation
environment
epigenetics
all of the above

Answer 45

all of the above

Question 46

In many organisms, organelles, such as mitochondria, are transmitted only via the egg. This phenomenon is known as ___.

Answer 46

maternal inheritance

Question 47

In which phase of the cell cycle are chromosomes replicated?

Answer 47

S phase

Question 48

Some genes are not located on chromosomes in the cell nucleus, but in organelles. Which of the following has extranuclear genome?
mitochondrion
chloroplast
lysosome
two of the above
all of the above

Answer 48

two of the above

Question 49

Somatic cells reproduce themselves through ___.

Answer 49

mitosis

Question 50

Meiosis creates genetic diversity through _____.

Answer 50

Random separation of homologous chromosomes and Crossing-over of sister chromatids