ch 9

which of the following is a characteristic of double-stranded DNA?

2 nanometers in width 10 base pairs per turn 0.34 nanometers per base pair

Which of the following DNA sequences is complementary to 5' TAGAC 3'?

5' GTCTA 3'

According to Chargaff's rule, which of the following statements about double-stranded DNA is NOT true?

A + T = C + G

Which of the following DNA molecules is the most stable?

GCGTGCAC CGCACGTG

Unzipping the DNA helix

Helicase

Which is the correct order of events when a protein is made in the process of translation?

Initiation, elongation, termination

Final binding of nicks in DNA during synthesis and repair

Ligase

Synthesizing an RNA primer

Primase

The processes of transcription and translation differ between prokaryotes and eukaryotes in the following way:

Prokaryotes transcribe and translate simultaneously.

Which type of plasmids confer the ability of an organism to survive treatment by antibiotics?

R factors

Before the lagging strand can begin assembling new DNA nucleotides, which of the following must occur?

RNA primase constructs a short RNA primer.

If one strand of DNA contains the bases ACAGT, what would be the complementary bases on the mRNA strand?

UGUCA

What happens when a hairpin loop forms in mRNA?

The RNA polymerase and the mRNA dissociate from the DNA.

Repressible operons (such as the arg operon)

are usually in the "on" mode

Which of the following is a true statement concerning protein synthesis in eukaryotic organisms?

Transcription occurs in the nucleus and translation occurs in the cytoplasm.

Introns are removed and exons are spliced together

before translation

Nucleotides are the building blocks of

both DNA and RNA.

DNA polymerase

can only add nucleotides in a certain direction.

are groups of three bases in mRNA that specify one amino acid in the amino acid chain

codons

Which of the following require physical contact between two bacterial cells for DNA transfer?

conjugation

The following pertain to ribosomes during protein synthesis except

contain codons within their rRNA molecules

What binds with an inactive repressor to make an active repressor?

corepressor

Which pentose sugar is found in DNA?

deoxyribose

A nucleotide is oriented 5' or 3' depending on the location of the _______ on the strand of DNA.

deoxyribose carbons

The DNA of a chromosome is ___-stranded.

double

One bacterial chromosome replicates to become two chromosomes with

each made of one strand of DNA from the original chromosome and one newly synthesized strand.

In eukaryotic cells, gene expression is regulated in response to ___ stimuli such as nutrient and toxin levels, and also during growth and ___ .

environmental, development

Proteins that remove incorrect bases and replace them with correct ones are termed ______ repair enzymes.

excision

The process in which mutations are removed and replaced with the correct bases is called

excision repair

The purpose of RNA synthesis is to provide a new copy of DNA as the original strand deteriorates over time

false

The trp operon consists of __________ structural gene(s).

five

A sequence of bases within a gene that will be transcribed, but removed from the transcript prior to translation is a/an

intron

Eukaryotic mRNA contains non-coding regions called ______.

introns

Which DNA sequences are found within a gene but do not encode the protein specified by that gene?

introns

are DNA sequences found within a gene that do not encode the protein corresponding to the gene.

introns

When a repressor binds to the operator site on DNA

it blocks RNA polymerase and mRNA synthesis.

The lac repressor binds to what site within the lac operon?

lacO

What molecule is synthesized as a copy of a gene from the DNA template strand?

mRNA

Which of the following types of RNA is the transcribed version of a structural gene in DNA, that is later read for translation into protein?

mRNA

The three types of RNA are

messenger, transfer, ribosomal

A ____ is the basic unit of DNA structure.

nucleotide

RNA is a chain of

nucleotides

Which of the following occurs first in transcription?

formation of a holoenzyme

addition or deletion of bases that changes the reading of mRNA codons

frameshift mutation

A segment of DNA encoding a protein or an RNA molecule is a

gene

The complete set of chromosomes and genes in an organism is referred to as the

genome

Which term represents all of the genetic information within a cell?

genome

Which is incorrect about inducible operons?

have genes turned off by a buildup of end product

The enzyme that unwinds a segment of the DNA molecule is

helicase.

is another term for genetics--the study of inheritance in living things.

heredity

dsDNA

herpesvirus

Eukaryotic chromosomes differ from prokaryotic chromosomes because only eukaryotes have

histone proteins chromosomes in a nucleus several to many chromosomes elongated linear, not circular, chromosomes

The initial transfer RNA occupies the __________ on the ribosome.

p site

The bond connecting amino acids is a(n) ____ bond.

peptide

A __________ is the physical expression of the genes present and can change depending upon what genes are turned "on."

phenotype

is a small circular segment of DNA found in the cytoplasm of bacteria that is capable of independent replication and usually contains nonessential genes.

plasmid

Hfr transfer involves all of the following except

plasmid gene transfer

Mutations that involve the addition, deletion or substitution of one or a few bases are referred to as _______ mutations.

point

Which of the following are parts of a nucleotide in DNA?

phosphate, nitrogenous base, deoxyribose sugar

The correct structure of DNA components can be presented as

phosphate-sugar-base.

Which process repairs DNA that has been damaged by ultraviolet radiation using visible light?

photoactivation

Donor and recipient bacterial cells are connected by the sex ___ during conjugation

pili

refers to the transfer of genes from donor to recipient microorganisms, where the recipient strain shows a change in genetic makeup at the end.

recombination

The ___ of the genetic code results in several codons encoding the same amino acid.

redundancy

___ RNA may exert control on several levels in both prokaryotes and eukaryotes.

regulatory

During semiconservative _____ the DNA is duplicated prior to binary fission.

replication

ssRNA

poliovirus

What must occur prior to cell division to ensure that each new cell has a complete set of DNA chromosome(s)?

replication

The site where the old DNA strands separate and new DNA strands will be synthesized is called the

replication fork

Transcription begins when RNA polymerase binds to the

promoter on DNA

DNA polymerases are responsible for

proofreading/repair. building the DNA chain.

The ___ protein is capable of repressing an operon.

repressor

The protein product of a repressor gene is the ___ which binds the operator to stop transcription.

repressor

Split genes

require spliceosomes to excise introns and then join exons.

DNA polymerase

requires a template for the synthesis of DNA. Correct

Which pentose sugar is found in RNA?

ribose

Protein synthesis occurs on ____.

ribosomes

DNA replication is said to be

semi-conservative

During ___ DNA replication, the newly made double helices are composed of one parent template and one newly synthesized strand.

semiconservative

___ mutations in DNA are caused by random mistakes in replication and not known to be influenced by any mutagenic agent.

spontaneous

random change in the DNA arising from errors in replication that occur without a known cause

spontaneous mutation

Which are components of an operon in a sequence of DNA?

structural genes, operator

changing of single base in the DNA code that may result in the placement of a different amino acid

substitution mutation

The RNA molecules that carry amino acids to the ribosomes during protein synthesis are called

tRNA

During replication, each parent DNA strand serves as a __________ for synthesis of new DNA strands.

template

The Rho protein is involved in the __________ stage of transcription.

termination

Full induction of the lactose operon requires

that lactose be present without glucose.

In some degradative pathways, in the absence of an inducer (e.g., arabinose)

the activator protein can't bind to DNA, and RNA polymerase can't bind to the promoter site. Correct

Translation is characterized by

the blueprint of the RNA molecule used to bind amino acids together to form proteins.

Two different mechanisms for copying the DNA strands are used because

the strands are oriented in opposite directions. Correct

The process of transcription is similar to

the synthesis of the leading strand during DNA replication.

The term , ___ or codon, is a sequence of 3 nucleotides in DNA that encodes an amino acid.

triplets

In the presence of tryptophan, tryptophan binds to the

trp repressor.

If you know the sequence of nucleotides in mRNA, you can deduce the DNA sequence it was transcribed from.

true

Unlike DNA, RNA is usually single-stranded.

true

In RNA, which nitrogenous base pairs with adenine?

uracil

The nitrogenous base thymine is only found in DNA, while ___ is only found in RNA.

uracil

Vancomycin-resistant enterococci (VRE) arise when, through genetic transfer, a MRSA strain acquires the operon _____ located within a _______.

vanA, transposon

Put the following steps in order describing the viral process of a retrovirus, such as HIV.

viral RNA ssDNA dsDNA new viral RNA

A mechanism that blocks transcription

will block the production of mRNA.

The process of __________ always results in the same genes being transferred between bacteria.

specialized transduction

Supercoiling

Gyrase

retrovirus

HIV

In a chromosome, the DNA is composed of ______ strands.

2

If the codon GGU is positioned in the A site of the ribosome, which of the following will occur

A tRNA with the anticodon CCA will deliver its amino acid to the site

Which component of DNA determines the 3' and 5' ends of the strands?

Carbons in the deoxyribose sugar

Which of the following best describes transcription?

DNA -> RNA

Which best describes the flow of genetic information in a cell?

DNA encodes RNA which encodes protein

The enzyme that travels along the leading strand assembling new nucleotides on a growing new strand of DNA is

DNA polymerase

Removing RNA primers, replacing gaps between Okazaki fragments with correct nucleotides, repairing mismatched bases

DNA polymerase I

Adding bases to the new DNA chain, proofreading the chain for mistakes

DNA polymerase III

The flow of genetic information in a cell is a process starting with ___ which encodes ___ which encodes protein

DNA, RNA

Genetic inheritance in microorganisms is best defined by which term?

Heredity

in bacterial conjugation, which type of donor has the fertility factor integrated into the chromosome?

Hfr

DNA polymerase ____ is the main enzyme involved in the building of the new DNA chain, whereas DNA polymerase ____ is involved mostly with removing the primers and repairing damaged DNA.

III/I

Which of the following is correct regarding sigma factor?

It recognizes the promoter region.

On one of the strands of bacterial DNA, the new complementary strand is synthesized discontinuously into small pieces of DNA called

Okazaki fragments.

What three components make up RNA structure?

Phosphate, nitrogenous base, ribose sugar

The main enzyme responsible for transcription is

RNA polymerase

Which of the following are functions of RNA polymerase?

Synthesizes an RNA molecule from DNA template Unwinds the DNA so that transcription can take place

After mRNA is made, what generally occurs?

The mRNA is translated to protein.

What is the purpose of the Ames test?

To determine the carcinogenic potential of a chemical

Transcription is characterized by

a messenger RNA molecule synthesized from the DNA molecule in the nucleus.

Genetic transfer of ______ to a methicillin-resistant Staphylococcus aureus (MRSA) strain produces vancomycin resistant enterococci (VRE).

a transposon containing the vanA operon

If an organism lost the ability to make primase, what would it be unable to do?

add a short sequence of complementary RNA to the existing DNA strand Correct

The two strands of the DNA molecule are

antiparallel

Synthesis of mRNA is

in the 5' to 3' direction with new nucleotides being added to the 3' end of the mRNA molecule

In the absence of tryptophan, the trp repressor is

inactive and cannot bind to the operator.

result from exposure to known mutagens, which are primarily physical or chemical agents that damage DNA

induced mutation

If the wild type DNA sequence reads THE CAT ATE THE BIG RAT, what type of mutation would change the sequence to THE CAT ATE THE BAG RAT?

missense

The mechanisms of ___ transformation involve genes that can regulate cellular genomes and control the onset of cell division.

oncogenic

A(n) ______ is a cluster of genes that perform related functions found in ______

operon; prokaryotes Correct

Coordinated sets of genes that are regulated as a single unit are referred to as ______

operons

What component of RNA is different from one individual (or one bacterium) to the next?

order of nitrogenous bases

The site on a chromosome where DNA replication begins is called the ____ of replication.

origin

What usually terminates the process of translation?

presence of a stop codon on mRNA

Translation of mRNA into protein begins before transcription is complete in

prokaryotes only

are able to shift from one part of the genome to another.

transposons

The process of synthesizing RNA from a DNA template is

transcription

involves the transfer of DNA via bacteriophages.

transduction

Which of the following is not true of conjugation?

transfers genes for a polysaccharide capsule

Which gene transfer method involves the uptake of free DNA by competent bacterial cells?

transformation

"Jumping genes" are known as

transposons