Biology

How many nucleotides are contained in a single codon?

3

Which of the following base pairs would be targeted and repaired by a mismatch repair system

A-G

Which of the following base pairs would be targeted and repaired by a mismatch repair system?

A-G

Which of the following are points of control for gene expression in eukaryotes?

All of the choices are correct

Which of the following viruses can cause cancer

All of the choices are correct

________ enables a single gene to encode two or more polypeptides that are different in their amino acid sequence.

Alternative splicing

Who discovered that DNA was the genetic material or transforming factor that could convert nonvirulent R-type Streptococcus pneumoniae bacterium to the virulent S-type?

Avery, MacLeod, and McCarty

Which of the following does NOT occur during transcriptional regulation in eukaryotes?

Chromatin is converted to the closed conformation

of the following does NOT occur during transcriptional regulation in eukaryotes?

Chromatin is converted to the closed conformation.

Which molecule is responsible for separating double-stranded DNA into single strands?

DNA helicase

All of the following are critical factors for DNA replication on the leading strand EXCEPT?

DNA ligase

During DNA replication, all of the following proteins are important for separating the DNA strands and allowing movement of the replication fork EXCEPT

DNA polymerase

As part of the transcriptional unit, regulatory sequences are the sites where RNA polymerase and transcription factors bind to regulate transcription.

False

Different globin polypeptides are expressed at similar levels during the embryonic and fetal stages of mammalian development.

False

In eukaryotes, 40S and 60S combine to form a 100S ribosome.

False

Myc genes tend to be overexpressed in only a few forms of cancer

False

Small effector molecules directly bind the DNA they regulate.

False

Studies by Avery, MacLeod, and McCarty with different strains of bacteria and those by Hershey and Chase with T2 bacteriophage determined that proteins are highly complex molecules that form the genetic material for bacteria and viruses.

False

The cells of every organism make only a few different tRNA molecules encoded by the same gene.

False

The movement of DNA polymerase continues unimpeded if a thymine dimer is present in the DNA double helix.

False

The timing of a mutation during development has negligible effects on the severity of the genetic defect

False

Unmethylated CpG islands are correlated with inactive genes

False

tRNA contains the genetic code for producing a polypeptide.

False

At what phase of the cell cycle does p53 halt cell division if it senses DNA damage?

G1

What molecule provides the energy for translation?

GTP

Which of the following statements about RNA processing in eukaryotes is INCORRECT?

Introns are simply excised out of pre-mRNA to produce the mature mRNA.

Why is the operon arrangement of genes beneficial to certain bacteria?

It allows the coordinated regulation of a group of genes that encode proteins with a common function

Which of the following statements about RNA polymerase in bacteria is INCORRECT

It catalyzes the addition of nucleotides to the 5′ end of a growing RNA strand.

What is the effect of DNA methylation

It inhibits transcription

What is the effect of DNA methylation?

It inhibits transcription

________can convert proto-oncogenes into oncogenes

Nonsense mutations

Which of the following occurs when the cAMP-CAP complex binds the CAP site near the lac promoter?

RNA polymerase binds to the promoter and transcription rate increases.

Which of the following is NOT a criterion for an organism's genetic material?

The genetic material must be dynamic, changing rapidly in response to changes in the environment.

What is the function of the MutS protein in methyl-directed mismatch repair

To find mismatches.

A single gene always encodes for an enzyme

True

Bacteria can regulate gene expression by controlling the rate at which mRNA is translated into protein

True

Both eukaryotes and prokaryotes require a promoter region for gene transcription.

True

Certain types of cancer are caused by viruses

True

DNA is a double helix structure whose strands are held together by hydrogen bonds with A to T and C to G base pairing.

True

DNA is used as a template to make mRNA, which contains the information to make a polypeptide

True

DNA is used as a template to make mRNA, which contains the information to make a polypeptide.

True

Most oncogenes encode proteins that function in cell growth signaling pathways.

True

Mutations can produce a polypeptide with increased function

True

Okazaki fragments are sequences of DNA most often found on the lagging strand of DNA during DNA replication.

True

RNA polymerase II of eukaryotes always requires more than one general transcription factor to initiate transcription

True

RNA polymerase II of eukaryotes always requires more than one general transcription factor to initiate transcription.

True

RNA polymerase can bind to the promoter region of the DNA even when the lac repressor is bound to the operator site.

True

Should a genetic abnormality arise, ________ prevent a cell from progressing uncontrollably through the cell cycle

checkpoint proteins

The lac operator site within the lac operon is an example of which of the following?

cis-acting element

Some genes such as that for β-actin are expressed at relatively constant levels in tissues regardless of variations in the animal's condition. What do we call this type of gene?

constitutive gene

Eukaryotic DNA methylation occurs on which base

cytosine

The most common eukaryotic ribosome carries out its function in the

cytosol.

Because more than one codon can specify the same amino acid, the genetic code is said to be

degenerate.

Ionizing radiation can produce which of the following

free radicals

Once the lac repressor binds to the lac operator site, RNA polymerase is prevented from transcribing which genes?

galactosidase and galactoside transacetylase genes

A(n) ______ is an organized unit of DNA sequences that enables a segment of DNA to be transcribed into RNA and ultimately results in the formation of a functional product

gene

The ability of cells to control their level of gene expression is called

gene regulation

Which purine base forms 3 hydrogen bonds when binding its complementary nucleotide base?

guanine

The protein of T2 bacteriophage is labeled with 35S and the DNA with 32P. Where would one detect most of the 32P if the T2 bacteriophage were allowed to infect the bacteria

inside the infected bacteria

The protein of T2 bacteriophage is labeled with 35S and the DNA with 32P. Where would one detect most of the 32P if the T2 bacteriophage were allowed to infect the bacteria?

inside the infected bacteria

This molecule catalyzes covalent bond formation between fragments of DNA.

ligase

Which of the following CANNOT be repaired by nucleotide excision repair (NER)?

mismatched bases

Which of the following LEAST belongs with the others

nucleotide excision repair

___________ are the building blocks of DNA.

nucleotides

A ________ bond holds the amino acids of a growing polypeptide chain together during the elongation stage of translation.

peptide

In producing a strand of DNA the nucleotides combine to form what type of bond?

phosphodiester

________ is directly produced from the transcription of a eukaryotic gene.

pre-mRNA

Which factors are needed to recognize the stop codon and disassemble the translation machinery?

release factors

A physician discovered a cancerous tumor in the cartilage of a patient. What type of tumor is this?

sarcoma

The mechanism of DNA replication is

semiconservative.

Which of the following serves as the "translator" or intermediary between an mRNA codon and an amino acid?

tRNA

The process that produces mRNA from DNA is called

transcription

Which protein influences the ability of RNA polymerase to transcribe genes?

transcription factors

How many distinct aminoacyl-tRNA synthetases does each cell make?

~20

Liver cells, mammary cells, and skin cells all contain the same genome; however, their respective proteomes vary drastically. This observation is best explained by what phenomenon?

cell differentiation

Which of the following would represent the "transformation principal" first proposed by Griffith through his studies on Streptococcus pneumoniae bacterium?

.DNA

How many replication forks are there at a replication origin?

2

Where is the response element found in eukaryotic genes?

50 to 100 base pairs upstream from the transcriptional start site

The lacP site lies within the lac operon and is upstream of the genes that encode for proteins involved in lactose uptake and metabolism. Which of the following statements is TRUE of the lacP site?

It is the lac promoter site where RNA polymerase binds.

________ attaches DNA sequences at the ends of eukaryotic chromosomes

Telomerase

which of the following statements about the mRNA start codon is INCORRECT?

The start codon is usually GGA

All of the following are chemical mutations EXCEPT

X-rays

The lacA gene found within the lac operon encodes for galactosidase transacetylase. This enzyme attaches a(n) ________ group to lactose and lactose analogs

acetyl

All of the following nucleotide bases are pyrimidines EXCEPT

adenine

The term N-terminus refers to the presence of a(n) ________ at the 5′ end of a polypeptide.

amino group

The ability of glucose to repress the lac operon depends on which of the following effector molecules?

cAMP