Deck 8: DNA: The Chemical Nature of the Gene

Question 1

Which form of DNA has a left-handed helix and its sugar-phosphate backbone zigzags back and forth?

A)A-DNA
B)B-DNA
C)Z-DNA
D)All forms of DNA have this secondary structure.

Answer 1

C
Z-DNA

Question 2

The genes for ribosomal RNA and transfer RNA contain which kind of the three major classes of DNA?

A)highly repetitive DNA
B)moderately repetitive DNA
C)unique-sequence DNA
D)It varies from gene to gene.

Answer 2

B
m oderately repetitive DNA

Question 3

DNA consists of repeating units of nucleotides.Which is NOT a component of a nucleotide?

A)a ribose sugar
B)purine or pyrimidine nitrogen-containing bases
C)a deoxyribose sugar
D)phosphate
E)DNA contains all of the above.

Answer 3

A
a ribose sugar

Question 4

Which is NOT true of most bacterial DNA?

A)It is packaged into a confined space using proteins.
B)It appears as a distinct clump called a nucleoid.
C)It is linear.
D)It exists in a series of twisted loops.

Question 5

Which is NOT one of the tools that Watson and Crick used to solve the structure of DNA?

A)all available data on the chemistry of DNA
B)model building of possible structures
C)Rosalind Franklin's X-ray diffraction data of DNA
D)new and revolutionary experimental data that they collected themselves
E)all of the above

Question 6

Telomeres _________ the end of chromosomes.

A)transcribe
B)replicate
C)stabilize
D)destabilize

Question 7

Which is true of the secondary structure of DNA?

A)Nucleotide bases are on the outside of the DNA molecule.
B)Sugar-phosphate groups are on the inside of the DNA molecule.
C)Bases on complementary strands are held together by hydrogen bonds.
D)Cytosine pairs with adenine.
E)Thymine pairs with guanine.

Question 8

The packaging of DNA into a confined space is what level of DNA structure?

A)primary
B)secondary
C)tertiary
D)quaternary

Question 9

Heterochromatin is characterized by all of the following,EXCEPT that it

A)is present all over the inactive X chromosomes in mammals.
B)contains genes that require high levels of transcription.
C)is present on most of the Y chromosome.
D)remains highly condensed throughout the cell cycle.
E)is present at centromeres and telomeres.

Question 10

Before DNA was known to be the genetic material,scientists knew that genetic material must do or be all of the following,EXCEPT that

A)genetic material must contain complex coding information.
B)genetic material must be composed of many different units to account for the variability seen in nature.
C)genetic material must replicate faithfully.
D)genetic material must encode the phenotype.

Question 11

What would Avery,Macleod,and McCarty have concluded if their results had been that only RNAse treatment of the heat-killed bacteria prevented transformation of genetic virulence?

A)that DNA was the genetic material
B)that RNA was the genetic material
C)that protein was the genetic material
D)that DNAse or protease,but not RNase,stimulates transformation

Question 12

If a piece of chromatin contained 200 copies of the histone H4,then how many nucleosomes would be present?

A)100
B)200
C)400
D)We cannot say: nucleosome structures are randomly placed throughout chromatin.

Question 13

What would Hershey and Chase have concluded if phage ghosts contained ³²P label but were absent from infected E.coli? Furthermore,they found ³⁵S lacking in the ghosts and present in the infected E.coli.

A)that protein was the genetic material in phage
B)that DNA was the genetic material in phage
C)that somehow the radioactivity prevented DNA from getting into E.coli
D)that protein and DNA together made up the genetic material

Question 14

Which statement is true regarding negative supercoiled DNA?

A)That negative supercoiled DNA is underrotated allows for easier strand separation during replication and transcription.
B)Negative supercoiled DNA is not usually seen in cells.
C)Negative supercoiled DNA has 10 base pairs per turn of its helix.
D)Negative supercoiled DNA carries more negative charges than positive supercoiled DNA does.
E)All of the above statements are true.

Question 15

According to Chargaff's rules,if a genome is 30% adenine,then what percentage of the genome should be guanine?

A)30%
B)35%
C)40%
D)20%
E)70%