Biology final test

The start codon of an mRNA specifies which of the following amino acids?

Methionine

What type of repair mechanisms is responsible for removing bases that were incorrectly inserted into DNA during replication?

Mismatch

repair is responsible for removing bases that were incorrectly incorporated into DNA during replication.

Mismatch

A is a heritable change in the nucleotide sequence of DNA and is the source of genetic diversity leading to evolution.

Mutation

Which of these is not required for DNA replication?

NADPH

repair multiple kinds of lesions in DNA, using a single mechanism

Non-specific

How many aminoacyl-tRNA synthetases are present for each of the 20 common amino acids?

One

What is the name of the subunit that acts as the sliding clamp, which keeps the replicating enzyme complex attached to the template in eukaryotic cells.

PCNA

The enzyme peptidyl transferase is required in the formation of bonds by the ribosome.

Peptide

This type of mutation happens when a single base in DNA is substituted with another base, for example, an A becomes a G.

Point

Choose all characteristics of the transforming substance isolated by Avery, MacLeod and McCarty.

RNA-digesting enzymes did not affect its transforming ability. The elemental composition of the substance was very similar to that of DNA. DNA-digesting enzymes destroyed its transforming ability. Protein-digesting enzymes did not affect its transforming ability.

In translation termination, stop codons are recognized by what type of proteins?

Release factors

Alternative splicing allows which of the following?

A single transcript can be spliced into different mRNAs

In most cases, the start codon in mRNA is

AUG

is an inherited disease and the patients with this disease produce urine that contains homogentisic acid

Alkaptonuria

Which process can produce multiple transcripts from the same gene in eukaryotes?

Alternative splicing

Identify the physician who, in the early 1900s, proposed a relationship between genes and the production of enzymes.

Archibald Garrod

Consider the pathway for synthesis of arginine from glutamate by Neurospora crassa as shown on the diagram. A mutant for the argG gene will be able to grow on minimal media supplemented with which of the following

Arginosuccinate Arginine

For proteins that are targeted to the ER, where is the signal sequence usually located?

At the beginning of the protein (first several amino acids added during translation)

Nucleotides contain a sugar, a phosphate, and a nitrogenous

Base

Place the types of mutations found in humans in the correct order going from most frequent (on top) to least frequent (at the bottom).

SNV mutations Indels mobile element insertion CNV mutation

According to recent finding on human mutation rates based on genome sequencing, what is the most common type of mutation in humans?

SNVs

Before it can bind to the promoter, a eukaryotic RNA polymerase II has to be recruited by

Several transcription factors

Which enzymes did Avery, MacLeod, and McCarty use in order to identify the genetic material?

DNA digesting enzymes RNA digesting enzymes protein digesting enzymes

The enzyme that relieves DNA supercoiling ahead of the replication fork is

DNA gyrase

The DNA controlled by an origin is called a

replicon

DNA replication that leads to the production of double helices with one parental strand and one newly synthesized strand is consistent with

semiconservative replication

When the double stranded DNA helix is unwound, two single strands of DNA are formed. These strands have to be stabilized because their hydrophobic bases are exposed to water. The proteins that stabilize the two single strands are called

single strand binding proteins

The two general categories of DNA repair are

specific, nonspecific

several differences in prokaryotic and eukaryotic replication.

structure of chromosome (linear vs. circular) complexity of enzymology number of origins of replication

following that are components of a nucleotide.

sugar. phosphate nitrogenous base

The DNA backbone is composed o

sugars, phosphate groups

which 3 items are required for DNA replication

template nucleotides polymerase

The end of a bacterial transcription unit is marked by a

terminator sequence

Griffith's experiments were important because they showed

that the genetic material could be passed from one cell to another

target a single kind of lesion in DNA and repair that damage

Specific

Identify the process the pre-mRNA undergoes to create a functional mRNA.

Splicing

The process of alternative can produce different transcripts from the same gene in eukaryotes.

Splicing

Which of the following describes how proteins are targeted for translation to the rough ER?

The initial amino acid sequence of these proteins serves as a signal sequence that targets them to the rough ER.

What is the function of the promoter in a bacterial transcription unit?

To form a recognition and binding site for RNA polymerase

Griffith performed experiments, which demonstrated

Transformation in bacteria

Which of the following refers to the RNA-to-protein step in the expression of genes?

Translation

Which of the following sets of nucleotides is a valid mRNA codon?

UUC

helicase

Use ATP to unwind the DNA template

accurately describe the transcription bubble.

The growing RNA strand protrudes from the bubble It contains an RNA-DNA hybrid, about 9 nt long It moves along the DNA at a rate of about 50nt/sec

Features of the Watson and Crick model include

a double stranded structure a helical structure a sugar phosphate backbone

Bacterial DNA is typically replicated as

a single replicon

When scientists synthesized an RNA molecule made of U (polyU) and translated it in cell-free translation systems, they produced a protein made of

a string of the same AMINO acid

Most mature eukaryotic mRNAs have a string of nucleotides referred to as a poly- tail.

adenine

The major significance of the Hershey and Chase's experiments is that they

determined that DNA is genetic material

Franklin X-ray to suggest that DNA has a helical structure.

diffraction

An ______ cuts DNA internally and an ______ cuts at the ends of DNA.

endonuclease; exonuclease

Archibald Garrod concluded that patients suffering from alkaptonuria lack the necessary to catalyze the breakdown of homogentisic acid.

enzyme

Based on replication proteins, DNA replication in archaea is most similar to that of

eukaryotes

Which types of cells have more than one origin of replication?

eukaryotes

This type of primase is a combination of RNA polymerase and DNA polymerase that makes short RNA primers and then extends them with DNA to produce the final primer:

eukaryotic

E. coli polymerases I, II, and III have 3' to 5' activity, which provides them with a proofreading function, i.e. they can remove a mispaired base.

exonuclease

The term gene refers to gene function either at the level of traits or at the molecular level.

expression

What term can refer to gene function at the level of traits or at the molecular level?

gene expression

Eukaryotic genes may contain non-coding regions known as because they interrupt the sequence of a gene.

introns

To create a functional RNA, the pre-mRNA undergoes a process known as splicing. During the splicing process, the are removed and the remaining are connected to each other.

introns, exons

Synthesized in small fragments that are later connected

lagging strand

Identify the 2 subunits of a ribosome.

large, small

The two subunits that make up any ribosome are called the subunit and the subunit.

large, small

The enzymes in the replisome are active on

leading and lagging strands

synthesized continuously

leading strand

During DNA replication, the strand is synthesized continuously while the strand is synthesized as small fragments that are connected to each other to form a continuous strand.

leading, lagging

DNA replication in eukaryotic cells is complicated by the fact that eukaryotic cells have

linear chromosomes

primase

make a 10-12bp complementary primer to the DNA

Ribosomes cannot directly process DNA to synthesize polypeptides; they can only translate a specific type of RNA transcript, the RNA.

messenger

In eukaryotes, an intermediate is needed to carry the information in DNA to the ribosome in the cytoplasm. This intermediate is

messenger RNA

Agents that cause mutation are known as

mutagens

Radiation, UV light, x-rays, and chemicals in the environment can cause mutations in DNA and are therefore referred to as

mutagens

List several differences in prokaryotic and eukaryotic replication.

number of origins of replication complexity of enzymology structure of chromosome (linear vs. circular)

Each aminoacyl-tRNA synthetase present in a cell recognizes of the 20 common amino acids. (indicate the number)

one

How many RNA polymerases are found in prokaryote

one

During semiconservative DNA replication

one of the strands in each new double helix comes from the original molecule, and one is newly synthesized.

Repeating sugar and phosphate units in a single DNA strand make up the

phosphodiester backbone.

mutations, also known as single variations change only a single base in the sequence of DNA.

point, nucleotide

X-ray diffraction was used to determine that the diameter of a DNA molecule is

2nm

Which of these is not a modification of eukaryotic transcripts?

3' cap

How was the genetic code deciphered?

By using cell-free biochemical systems to produce proteins based on synthetic mRNAs

The universality of the genetic code is evidence for which of the following?

Common evolutionary heritage

In their experiments, Avery, MacLeod, and McCarty isolated a substance, which had a transforming activity. Which of the following destroyed that substance's ability to transform bacterial cells?

DNA digesting enzymes

Select the functions of the ribosome.

Decoding the transcribed message Forming peptide bonds

The two main eukaryotic DNA polymerases that extend DNA are

Delta, epsilon

Which of the following is a mutation that changes the structure of the chromosome itself?

Duplication

Charged tRNAs are brought to the A site in the ribosome by an elongation factor called

EF-Tu

Which have three different RNA polymerases?

Eukaryotes

In order to bring a tRNA to the A site of the ribosome, the elongation factor EF-Tu must bind to a charged tRNA and

GTP

In which of the following chromosomal entities are an individual's traits specified?

Genes

The universality of the code is one of the strongest pieces of evidence suggesting that all living things share a common evolutionary heritage.

Genetics

Which of the following enzymes involved in DNA replication are found at the replication fork in all three types of cells (bacterial, archaeal, and eukaryotic)? Choose all that apply.

Helicase Clamp loader Sliding clamp Primase Polymerases

The experiments with radioactively labeled phage that showed that DNA was the genetic material were performed by

Hershey and Chase

The noncoding DNA sequences in a gene are termed which of the following?

Introns

In the transcription elongation complex of eukaryotes, what is the function of the CTD?

It acts as a platform, which recruits elongation factors and RNA-modifying enzymes

In the transcription elongation complex of eukaryotes, what is the CTD made of?

It consists of 7 amino acids repeated many times.

What is the name of the regions at the ends of eukaryotic chromosomes?

Telomeres

Which of the following are short repeats of DNA on the ends of eukaryotic chromosomes?

Telomeres

Typically, the ribosome uses which AUG codon it encounters in an mRNA as a signal to start translation?

The first

In transcription, which DNA strand has a sequence that is identical to the produced RNA (except that U in RNA is T in DNA)?

The sense strand

In prokaryotes how do translation and transcription occur?

They are coupled

What is the nature of terminators in bacteria?

They are specific sequences in DNA

How do eukaryotic transcription factors help form the initiation complex?

They recruit RNA polymerase to the promoter

Inspect the diagram of the arginine synthesis pathway in Neurospora crassa. If an arginine nutritional mutant can grow on minimal media, supplemented with ornithine, we can conclude which of the following?

This mutant has a mutation in the argE gene.

How many nucleotide bases are in one codon?

Three

Why do eukaryotic cells have multiple origins of replication?

To ensure timely replication of multiple, relatively large chromosomes

The poly-A tail of most mature eukaryotic mRNAs is found

at the 3' end of the transcript

polymerase

attaches nucleotides to the 3' end of the DNA strand

mutations are changes that alter the structure of the chromosome itself.

chromosomal

Genes, which contain trait specifying information, are located on

chromosomes

In transcription, the DNA strand that is not copied is called the strand.

coding

The genetic code is read in groups of three nucleotide bases known as

codons

In the replisome, the is composed of primase, helicase, and accessory proteins that prime the lagging strand.

primosome

Transcription and translation of an mRNA molecule occur simultaneously in

prokaryotes

In a bacterial transcription unit, the role of the is to form a recognition and binding site for the RNA polymerase.

promoter

The function of telomeres is to

protect the ends of chromosomes

The results of the Hershey and Chase experiments suggested that DNA was the genetic material because

radioactive bacteriophage DNA was found in the cytoplasm of bacterial cells

gyrase

relieves coiling in DNA strands ahead of the replication fork

The region containing the RNA polymerase, the DNA template, and the growing RNA transcript is called the

transcription, bubble

During gene expression, the DNA-to-RNA step is known as , while the RNA-to-protein step is known as .

transcription, translation

In the central dogma, the RNA-to-protein step is termed

translation

What process involves the synthesis of a protein, and takes place on the ribosome?

translation

which takes place on the ribosome, is the synthesis of protein from an RNA transcript.

translation

The DNA structure proposed by Watson and Crick involves

two grooves (major and minor) a helical structure a sugar phosphate backbone