exam three Flashcards
All viruses have _____.
a capsid (protein coat)
a viral genome
mitochondria
two of the above
all of the above
two of the above
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.
b. provides a way to determine if an agent is a mutagen.
A replicated chromosome is composed of
two sister chromatids held together at the centromere.
Cell differentiation is driven by _____.
differential gene expression
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.
All of the above can have an epigenetic effect on gene expression.
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.
All of the above are advantages.
______ mutations lead to the entire organism carrying the mutations and can be passed on to offspring
Germ-line
____ may be the result of nondisjunction during meiosis.
Aneuploidy
A mutation in a single gene can have ____ on an individual’s phenotype.
multiple
Bacterial fertility plasmids (F factors) can be transferred from donor strains to recipient strains through ___.
conjunction
The Ras gene, which encodes an intracellular signaling protein, is an example of ____.
oncogenes
Which of the following represents homozygous dominant genotype?
HH
Hh
hh
HH
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
two of the above
Human beings are diploid organisms. A normal human somatic cell has ___ chromosomes.
two sets of chromosomes, a total of 46 chromosomes
_________ 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
two of the above
Human cancer development is a long process of accumulating genetic alterations, ultimately resulting in malignancy. This statement is ___.
true
DNA mutations are ______ events
random
The COVID-19 viral genome is ____.
ssRNA
The process whereby a cell’s morphology and function change is called ___.
differentiation
Chromosomal synapsis and crossing-over occur during ____.
meiosis
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.
Two affected parents have an unaffected offspring.
Which of the following gene mutations changes a single amino acid in a polypeptide?
missense mutation
Morphogens are _____.
molecules that convey positional information and promote changes in development
Checkpoints during the cell cycle are important because they
ensure the integrity of the cell’s DNA
In Triple X syndrome (XXX, female), ___ X chromosome(s) is (are) inactivated as Barr bodies.
two
Gene transfer in which a bacterial cell takes up bacterial DNA from the environment is called ___.
transformation
During mitosis, some mitotic spindle microtubules attach to ____ of sister chromatids.
Kinetochores
In terms of life cycle, many fungi and protists are _____.
haploid-dominant species
According to Mendel’s Law of Segregation, every gamete receives ___ of a gene.
one allele
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.
metaphase of meiosis I; T and t; R and r
The P53 gene, which encodes a G1 checkpoint protein, is an example of ____.
tumor-suppressor genes
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?
1/256
Genomic imprinting, such as imprinted Igf2 gene, _____ gene expression throughout the life of the individual.
inactivate or downregulate
Viroids are composed solely of ___ and infect plant cells.
a single-stranded circular RNA
Two hallmarks of stem cells are _____.
self-renewal and cell differentiation
Which of the following is not a commonly used model organism in animal development?
Fruit fly
Mouse
Zebrafish
Nematode worm
None of the above
none of the above
Three checkpoints in the eukaryotic cell cycle are ____.
G1 checkpoint, G2 checkpoint, and metaphase checkpoint
The process of acquiring genes from another organism without being the offspring of that organism is known as ____.
horizontal gene transfer
Genetic inheritance patterns include _____.
simple Mendelian inheritance
incomplete dominance
codominance
gene linkage
Mutagens can cause mutations by ___.
chemically altering DNA nucleotides and disrupting DNA replication.
HIV, a retrovirus, has a high mutation rate because ___.
reverse transcriptase lacks a proofreading function.
The majority of organismal traits are ____.
quantitative, continuous variation over a range of phenotypes
In biology, a series of changes in the state of a cell, tissue, organ, or organism is called ___.
development
During viral infection, attachment is usually specific to a particular cell type because ___.
the virus recognizes and binds to specific molecules on the surface of the host cell.
Which of the following can affect an individual’s traits?
action
gene mutation
environment
epigenetics
all of the above
all of the above
In many organisms, organelles, such as mitochondria, are transmitted only via the egg. This phenomenon is known as ___.
maternal inheritance
In which phase of the cell cycle are chromosomes replicated?
S phase
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
two of the above
Somatic cells reproduce themselves through ___.
mitosis
Meiosis creates genetic diversity through _____.
Random separation of homologous chromosomes and Crossing-over of sister chromatids
