chapter 9 sb

A codon contains how many nucleotides?

3

What is the length of a typical tRNA molecule?

75-95 bases

During translation elongation, peptide bonds form between:

Amino acids

What is the central dogma hypothesis of genetics?

DNA encodes RNA which encodes protein

Which is true regarding DNA replication?

Each new DNA helix contains one parent strand and one newly synthesized strand.

Which type of mutation is generally most harmful to cells?

Frameshift mutation

What is the result of a point mutation that changes a template gene sequence from 3'-TACGCCATATAT-5' to 3'-TACGCCATCTAT-5'?

Nonsense mutation

A mutation that affects only a single base pair in DNA is termed a(n) mutation.

POINT

Mutations that are generally most harmful to cells because they cause the greatest change in the amino acid sequence of a protein by change the reading frame of the mRNA are called mutations.

frameshift

Random fragments of host DNA are taken up by the bacteriophage during assembly in Blank______ transduction.

generalized

An agent that induces changes in DNA is a(n)

mutagen

A small number of are considered beneficial in that they provide the cell with a useful change in structure or physiology. Antibiotic resistance in bacteria is an example.

mutations

Early termination of the protein is the result of a Blank______ mutation.

nonsense

A fragment of DNA with the wild type sequence 5'-AGCTGACGACCAGGTGACCAG-3' is found in a mutant to be 5'-AGCTGAGGACCAGGTGACCAG-3'. The term that best describes this mutation is Blank______.

point mutation

During replication, the enzyme synthesizes primer sequences.

primase

The _____ of the lac operon is a gene that encodes a repressor protein.

regulator

A particular part of the host genome is included in the virus during Blank______ transduction.

specialized

True or false: The parent strands in a DNA molecule are used as templates to synthesize complementary strands of DNA.

true

Which of the following signifies translation termination?

A nonsense codon is reached and the peptide is released from the ribosome

The three methods of gene transfer in bacteria are , , and .

Blank 1: conjugation Blank 2: transformation Blank 3: transduction

The pentose sugar in RNA is , while in DNA the pentose sugar is .

Blank 1: ribose Blank 2: deoxyribose

Which two of the following statements are correct regarding DNA replication elongation?

DNA polymerase I removes the RNA primers used to initiate DNA synthesis. Replication proceeds at a rate of 750 bases per second.

In regard to DNA replication elongation, which two statements are correct?

DNA polymerase I removes the RNA primers used to initiation synthesis. DNA ligase joins the lagging strand fragments.

True or false: Operons are found in fungi and helminths.

False

True or false: Plasmids are insertion sequences that can lead to changes in genotype within a cell or between cells.

False Reason: Insertion sequences that can lead to changes in genotype within a cell or between cells are called transposons. Plasmids are small circular pieces of DNA.

Which strand is replicated continuously without segments during DNA replication?

Leading

True or false: Many copies of a specific protein can be synthesized from a single mRNA transcript in a polyribosomal complex.

True

True or false: Ribose is the pentose sugar in RNA.

True

True or false: The anticodon for the codon 5'-AUG-3' is 3'-UAC-5'.

True

The structure of DNA was discovered in 1953 by

Watson and Crick

Most bacterial plasmids carry an origin of replication and at most Blank______ genes.

a few dozen

The specific sequence of three mRNA nucleotides, based on a DNA triplet, that encodes a particular amino acid, is a(n)

codon

A recombinant is defined as an organism that

contains and expresses genes that originated in another organism

Ensuring that the DNA code will be maintained during cell growth and cell is one of the two essential effects of the structure of DNA.

division

Watson and Crick discovered the structure of DNA in 1953, and described it as a(n)

double helix

Binding of lactose to the lactose repressor protein causes the repressor to

leave the operator sequence

DNA segments that code for proteins are referred to as genes.

structural

DNA segments that code for proteins are referred to as

structural genes

Select the enzymes that function in DNA replication.

Ligase DNA polymerase Helicase

Which two of the following statements regarding plasmids are true?

Many bacteria carry plasmids in addition to their chromosome. Plasmids may contain genes that specify resistance to antibiotics.

During DNA replication, the lagging strand is replicated in a discontinuous manner forming fragments.

Okazaki

In bacteria, a regulatory gene, a control region, and structural genes collectively are referred to as a(n)

Operon

Which operational unit in bacteria consists of a regulatory gene, a control region, and structural genes?

Operon

Which antibiotic does NOT target transcription or translation in bacteria?

Penicillin

Which of the following is a type of mutation that affects only a single base pair in DNA?

Point

Which enzyme synthesizes primer sequences during replication initiation?

Primase

Which three of the following events in protein synthesis occur post-translationally?

Protein folding Removal of the formyl methionine Addition of cofactor

Which process in bacteria do the antibiotics in the group including erythromycin and spectinomycin specifically inhibit?

Protein synthesis

In the central dogma, DNA encodes which encodes protein.

RNA

The antibiotic rifamycin, used to treat tuberculosis, binds and inhibits the activity of

RNA polymerase

Which is the main event of transcription initiation?

RNA polymerase binds the DNA promoter

Which of the following occurs during transcription termination?

RNA polymerase reaches a terminator region.

Which two of the following statements regarding eukaryotic transcription and RNA processing are correct?

Splicing to remove introns occurs in the nucleus. A series of adenosines is added to the mRNA.

Which kind of gene encodes a protein?

Structural

Which two statements about DNA replication in bacteria and eukaryotes are correct?

Telomere DNA gets progressively shorter with each copy. Eukaryotes initiate replication from multiple origins of replication.

What determines the order of amino acids in the primary structure of a protein?

The DNA sequence of a gene

Which two statements regarding eukaryotic transcription and RNA processing are correct?

The exon-intron junction is recognized by a spliceosome. Transcription occurs before splicing.

Which two of the following statements regarding tRNA structure are correct?

The overall structure is termed a cloverleaf. tRNA has regions that are double-stranded RNA.

Which two of the following statements comparing DNA replication in bacteria and eukaryotes are correct?

Topoisomerases relieve the superhelical tension as DNA is replicated. Eukaryotic DNA is linear whereas bacterial DNA is circular.

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

Transformation

The uptake of free DNA by competent bacterial cells occurs during bacterial

Transformation.

Insertion sequences that can lead to changes in genotype within a cell or between cells are called "jumping genes" or

Transposons

The biosynthesis of the amino acid histidine requires several enzymes whose genes are organized in the his operon. The his operon would be expected to be active when the cell is growing in a medium containing Blank______.

a low concentration of amino acids

The regulator of the lac operon is a gene that encodes

a repressor protein

The arginine operon is "on" when the cell is

actively growing

The lactose repressor protein ihas two binding sites, one for the operator DNA sequence and another for lactose, the presence of two binding sites means that it is

allosteric

Nucleotide is to nucleic acid as is to protein.

animo acid

In DNA, the two strands of the helix are arranged in a(n) orientation

antiparallel

Binding of arginine to the arginine repressor protein causes the repressor to

bind to the operator sequence

True or false: Okazaki fragments are formed during DNA replication of the leading strand.

false

In DNA replication, unwinds (unzips) the double helix, primase synthesizes the short RNA primer, and DNA adds nucleotides to the new chain.

helicase polymerase

Because lactose is ultimately responsible for stimulating protein synthesis from the lac operon, it is called the

inducer

The binding of arginine to the arginine repressor protein causes the repressor to bind to the operator region. This happens because arginine

induces a conformational change in the protein

The binding of lactose to the lactose repressor protein causes the repressor to leave the operator region. This happens because lactose

induces a conformational change in the protein

Many catabolic operons are Blank______, while those that encode anabolic enzymes are Blank______. Multiple choice question.

inducible; repressible

Which molecule is the inducer of the lac operon?

lactose

In the lac operon the binds to the operator.

lactose repressor

A copy of the DNA template corresponding to a protein-encoding gene is

mRNA

During translation initiation, the ribosome binds to the RNA transcript.

messenger

Building blocks of DNA, called , contain the same sugar and phosphate, but different nitrogenous bases.

nucleotides

When a cell is actively growing, the arg operon is Blank______, and arginine is Blank______.

on; actively synthesized

The control locus of the lac operon contains a region of DNA that acts as an on/off switch for transcription called a(n) Blank______.

operator

The lactose repressor protein binds to the Blank______ of the lac operon.

operator

dna. is the enzyme that synthesizes DNA strands in the 5' to 3' direction.

polymerase

"Finishing touches" on proteins are termed Blank______ modification. Multiple choice question.

posttranslational

Protein synthesis is more efficient in prokaryotes than in eukaryotes for all of the following reasons except

prokaryotic ribosomes are 70S rather than 80S

RNA polymerase binds to the region of the DNA to initiate transcription.

promoter

The control locus of the lac operon is composed of the Blank______, a region of DNA that is recognized by RNA polymerase.

promoter

During protein synthesis, many copies of a specific can be synthesized from a single mRNA transcript in a polyribosomal complex.

protein

An organism that contains and expresses genes that originated in another organism is called a

recombinant

During DNA replication the newly made double helices are composed of one parent template and one newly synthesized strand and therefore the replication is considered

semiconservative

The following sequence is found at the beginning of a gene in the wild type: 5'-ATGCCAGGTCGTACA-3'. In a related strain of bacteria, the sequence is 5'-ATGCCCGGTCGTACA-3'. Since the codons CCA and CCC both encode proline, this mutation is best described as a _____ mutation.

silent

True or false: During DNA replication, both the leading and lagging strands are synthesized in the 5' to 3' direction.

t

In a DNA molecule the parent strands are used as a(n) templateBlank 1Blank 1 template , Correct Unavailable to synthesize a complementary strand of DNA.

template

The process of transcription Blank______ results in the release of a completed RNA transcript.

termination

The antibiotic rifamycin can be used to treat tuberculosis because

the drug is more active against bacterial RNA polymerase than the human enzyme

The lactose repressor protein is allosteric, meaning that it has two binding sites, one for Blank______ and another for Blank______.

the operator DNA sequence lactose

The different types of nucleotides in DNA contain

the same sugar and phosphate, but different nitrogenous bases

The process of introducing foreign genes to a plant cell by adding the DNA directly to the cell medium is termed

transfection

The process of introducing foreign genes to a yeast cell by adding the DNA directly to the cell medium is termed

transfection

Fill in the blank question. One reason protein synthesis is more efficient in bacteria than in eukaryotes because bacterial and are simultaneous.

Blank 1: transcription Blank 2: translation

What is the function of mRNA?

It carries a copy of a DNA sequence to the ribosome.

Which strand is replicated discontinuously in segments during DNA replication?

Lagging

Which best describes the antiparallel orientation of strands in DNA?

One strand is 5' to 3' and the other is 3' to 5'.

True or false: The structure of DNA is essential for providing variety since the order of nucleotides is responsible for the unique qualities of each organism.

true