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55 terms

Bio Exam 3

Mastering Bio Questions Ch16 and 17
STUDY
PLAY
Which of these is a difference between a DNA and an RNA molecule?
DNA is double-stranded, whereas RNA is single-stranded.
You can tell that an image of a DNA nucleotide apart from an RNA nucleotide because you see a _____.
sugar with two, and not three, oxygen atoms
In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.
1' ... 5'
Nucleic acids are assembled in the _____ direction.
5' to 3'
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.
thymine ... cytosine
Who demonstrated that DNA is the genetic material of the T2 phage?
Hershey and Chase
The radioactive isotope 32P labels the T2 phage's _____.
DNA
Hershey and Chase used _____ to radioactively label the T2 phage's proteins.
Sulfate 35
After allowing phages grown with bacteria in a medium that contained 32P and 35S, Hershey and Chase used a centrifuge to separate the phage ghosts from the infected cell. They then examined the infected cells and found that they contained _____, which demonstrated that _____ is the phage's genetic material.
labeled DNA ... DNA
_____ are the short sections of
DNA that are synthesized on the lagging strand of the relicating DNA.
Okazaki fragments
The new DNA strand that grows continuously in the 5' to 3' direction is called the ________.
leading strand
After replication is complete, the new DNAs, called ________ , are identical to each other.
daughter DNA
During DNA replication, an open section of DNA, in which a DNA polymerase can replicate DNA, is called a _________.
replication fork
The enzyme that can replicate DNA is called _________.
DNA polymerase
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.
thymine ... cytosine
After DNA replication is completed, _____.
each new DNA double helix consists of one old DNA strand and one new DNA strand
The first step in the replication of DNA is catalyzed by _____.
helicase
The action of helicase creates _____.
replication forks and replication bubbles
Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments?
DNA polymerase can assemble DNA only in the 5' to 3' direction
The synthesis of a new strand begins with the synthesis of a(n) _____.
RNA primer complementary to a preexisting DNA strand
An old DNA strand is used as a _____ for the assembly of a new DNA strand.
template
What catalyzes DNA synthesis?
DNA polymerase
Which of the following statements about DNA synthesis is true?
Primers are short sequences that allow the initiation of DNA synthesis.
Which part of a deoxynucleoside triphosphate (dNTP) molecule provides the energy for DNA synthesis?
Phosphate groups
Which of the following enzymes creates a primer for DNA polymerase?
Primase
Which of the following statements about Okazaki fragments in E. coli is true?
They are formed on the lagging strand of DNA.
Which of the following enzymes is important for relieving the tension in a helix as it unwinds during DNA synthesis?
Topoisomerase
True or false? Single-stranded DNA molecules are said to be antiparallel when they are lined up next to each other but oriented in opposite directions.
TRUE
Where would RNA polymerase
attach?
DNA
In his work with pneumonia-causing bacteria and mice, Griffith found that
some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic.
E. coli cells grown on 15N medium are transferred to 14N medium and allowed to grow for two more generations (two rounds of DNA replication). DNA extracted from these cells is centrifuged. What density distribution of DNA would you expect in this experiment?
one low-density and one intermediate-density band
A biochemist isolates and purifies various molecules needed for DNA replication. When she adds some DNA, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?
DNA ligase
In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?
A + G = C + T
The elongation of the leading strand during DNA synthesis
depends on the action of DNA polymerase.
The spontaneous loss of amino groups from adenine results in hypoxanthine, an uncommon base, opposite thymine in DNA. What combination of molecules could repair such damage?
nuclease, DNA polymerase, DNA ligase
In a nucleosome, the DNA is wrapped around
histones
What name is given to the process in which a strand of DNA is used as a template for the manufacture of a strand of pre-mRNA?
transcription
What name is given to the process in which the information encoded in a strand of mRNA is used to construct a protein?
translation
What name is given to the process in which pre-mRNA is edited into mRNA?
RNA processing
Polypeptides are assembled from _____.
amino acids
RNA processing converts the RNA transcript into _____.
mRNA
What is the process called that converts the genetic information stored in DNA to an RNA copy?
Transcription
DNA does not store the information to synthesize which of the following?
Organelles
Transcription begins at a promoter. What is a promoter?
A site in DNA that recruits the RNA Polymerase
Which of the following statements best describes the promoter of a protein-coding gene?
The promoter is a nontranscribed region of a gene.
What determines which base is to be added to an RNA strand during transcription?
Base pairing between the DNA template strand and the RNA nucleotides
Which of the following terms best describes the relationship between the newly synthesized RNA molecule and the DNA template strand?
Complementary
What happens to RNA polymerase II after it has completed transcription of a gene?
It is free to bind to another promoter and begin transcription.
Which of these correctly illustrates the pairing of DNA and RNA nucleotides?
GTTACG
CAAUGC
The direction of synthesis of an RNA transcript is _____.
5' —> 3'
During RNA processing a(n) _____ is added to the 5' end of the RNA.
modified guanine nucleotide
During RNA processing a(n) _____ is added to the 3' end of the RNA.
a long string of adenine nucleotides
Spliceosomes are composed of _____.
snRNPs and other proteins
The RNA segments joined to one another by spliceosomes are _____.
exons
Translation occurs in the _____.
cytoplasm