Bio Chapter 13
Polytene chromosomes of Drosophila salivary glands each consist of multiple identical DNA strands that are aligned in parallel structures. How could these arise?
Replication without separation
If a cell were unable to produce histone proteins, which of the following would likely be an effect?
The cell's DNA couldn't be packed into its nucleus.
At a specific area of a chromosome, the following sequence of nucleotides is present where the chain opens to form a replication fork: 3'- CCTAGGCTGCAATCC- 5' An RNA primer is formed starting at the underlined T of the template. Which of the following represents the primer sequence?
5'- ACGUUAGG- 3'
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
8%
In trying to determine whether DNA or protein is the genetic material, Hershey and Chase made use of which of the following facts?
DNA contains phosphorus, whereas protein does not.
Which enzyme catalyzes the elongation of a DNA strand in the 5' to 3' direction
DNA polymerase III
A new DNA strand elongates only in the 5' to 3' direction because
DNA polymerase can only add nucleotides to the free 3' end.
After mixing a heat-killed, phosphorescent (light-emitting) strain of bacteria with a living, nonphosphorescent strain, you discover that some of the living cells are now phosphorescent. Which observation(s) would provide the best evidence that the ability to phosphoresce is a heritable trait?
Desendants of the living cells are also phosphorescent.
Which of the following sets of materials is required by both eukaryotes and prokaryotes for DNA replication?
Double-stranded DNA, four kinds of DNA nucleotides, primers, origins of replication
During DNA replication, which of the following enzymes separates the DNA strands during replication?
Helicase
Why do histones bind tightly to DNA?
Histones are positively charged, and DNA is negatively charged
Which of the following statements best describes the eukaryotic chromosome?
It consists of a single linear molecule of double-stranded DNA plus proteins
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It joins Okazaki fragments together
Which of the following enzymes synthesizes short segments of RNA?
Primase
Which of the following statements descrives one difference between DNA replication in prokaryotes and DNA replication in eukaryotes?
Prokaryotic chromosomes have a single origin of replication, whereas eukaryotic chromosomes have many.
WHat is the function of topoisomerase?
Relieving strain in the DNA ahead of the replication fork.
Which of the following help(s) to hold the DNA strands apart while they are being replicated?
Single-strand binding proteins
In a linear eukaryotic chromatin sample, which of the following strands is looped into domains by scaffolding?
The 30-nm chromatin fiber
Which of the following characteristics can be determined directly from the X-ray diffraction photographs of crystallized DNA?
The diameter of the helix
Which is the function of DNA polymerase III?
To add nucleotides to the 3' end of a growing DNA strand
In a nucleosome, the DNA is wrapped around
histones
During DNA replication, which of the following enzymes covalently connects segments of DNA?
ligase
Which of the following lists of structures correctly represents the order of increasingly higher levels of organization of chromatin?
nucleosome, 30-nm chromatin fiber, looped domain
The leading and lagging strands of DNA formed during DNA replication differ in that
the leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction.
An Okazaki fragment has which of the following arrangements?
5' RNA nucleotides, DNA nucleotides 3'
In an analysis of the nucleotide composition of DNA, which of the following will be found?
A+G=C+T
Suppose you are provided with an actively dividing culture of Escherichia coli bacteria to which radioactive thymine has been added. What would happen if a cell replicates once in the presence of this radioactive base?
DNA in both daughter cells would be radioactive.
In DNA from any species, the amount of adenine equals the amount of thymine, and the amount of guanine equals the amount of cytosine. Which of the following investigators was (were) responsible for this discovery?
Erwin Chargaff
In his transformation experiments, what did Griffith observe?
Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
What is meant by the description "antiparallel" regarding the two strands of nucleic acids that make up DNA?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.