The main reason scientists thought that proteins, rather than DNA, were the carriers of genetic material in the cell was:
the large number of possible amino acids combinations
In the experiments of Griffith, the conversion of nonlethal R-strain bacteria to lethal S-strain bacteria:
was an example of the genetic exchange known as transformation
The first experimenters to use Griffith's transformation assay to identify the genetic material were:
Avery, MacLeod, and McCarty
Which of the following statements about DNA is false?
DNA is only found in eukaryotic cells
The bacteriophages used in Alfred Hershey's and Martha Chase's experiments showed that:
DNA was injected into bacteria
The two molecules that alternate to form the backbone of a polynucleotide chain are:
sugar and phosphate
Chargaff determined that DNA from any source contains about the same amount of guanine as __________.
cytosine
__________ used x-ray diffraction to provide images of DNA.
Franklin
X-ray diffraction studies are used to determine:
the distances between atoms of molecules
X-ray crystallography showed that DNA:
was a helix
__________ determined the structure of the molecule DNA.
Waston and Crick
The information carried by DNA is incorporated in a code specified by the:
specific nucleotide sequence of the DNA molecule
Why is DNA able to store large amounts of information?
Its nucleotides can be arranged in a large number of possible sequences
The portion of the molecule in box 5 of Figure 12-1 is:
a phosphate
In Figure 12-1, the portion of the molecule in box __________ is a pyrimidine.
1
The portion of the molecule in box 3 of Figure 12-1 is:
a purine
Hydrogen bonds can form between guanine and __________, and between adenine and __________.
cytosine; thymine
Two chains of DNA must run in __________ direction(s) and must be __________ if they are to bond with each other.
antiparallel; complementary
Which of the following nucleotide sequences represents the complement
to the DNA strand
5¢ - AGATCCG- 3¢?
3¢-TCTAGGC-5¢
When DNA copies itself,
the two stands separate and both serve as templates
Which of the following best describes semiconservative replication?
A DNA molecule consists of one parental strand and one new strand
The final product of DNA replication is:
two DNA molecules, each of which contains one new and one old DNA strand
Who first confirmed that the replication of DNA was semiconservative?
Meselson and Stahl
If DNA replication rejoined the 2 parental strands, it would be termed:
conservative
Meselson and Stahl separated DNA from different generations using:
the mutation is corrected by the DNA polymerase enzyme
When a DNA molecule containing a wrong base at one location in one strand is replicated:
The mutation is copied into one of the two daughter molecules
Which of the following causes the unwinding of the DNA double helix?
DNA helicase
A replication fork:
is a Y shaped structure where both DNA strands are replicated simultaneously
In replication, once the DNA strands have been separated, reformation of the double helix is prevented by:
single strand binding proteins
Enzymes called __________ form breaks in the DNA molecules to prevent the formation of knots in the DNA helix during replication.
topoisomerases
What prevents knot formation in replicating DNA?
topoisomerase
Which of the following adds new nucleotides to a growing DNA chain?
DNA polymerase
Why does DNA synthesis only proceed in the 5¢ to 3¢ direction?
Because DNA polymerases can only add nucleotides to the 3c end of a polynucleotide strand
The 5¢ end of each Okazaki fragment begins with:
A separate RNA primer
DNA primase is the enzyme responsible for:
making short strands of RNA at the site of replication initiation
The DNA strand that is replicated smoothly and continuously is called the:
leading strand
In DNA replication, the lagging strand:
is synthesized as a series of Okazaki fragments
Okazaki fragments are joined together by:
DNA ligase
How is the chromosome of a bacterial cell replicated?
The circular DNA molecule is replicated from one origin of replication bidirectionally
How are the chromosomes of a eukaryote cell replicated?
The linear DNA molecules are replicated from multiple origins of replication bidirectionally
Refer to Figure 12-2. The correct designation for the DNA strand labeled C is:
A strand serving as a template
Refer to Figure 12-2. The segments labeled F are responsible for:
initiating DNA synthesis
Refer to Figure 12-2. The enzyme represented by the letter D is responsible for:
linking short DNA segments
Refer to Figure 12-2. The structures represented by the letter E are called:
Okazaki fragments
Which of the following statements concerning nucleotide excision repair is FALSE?
it is a type of mismatch repair
__________, the ends of eukaryotic chromosomes, shorten with every cell replication event.
telomeres
The ends of eukaryotic chromosomes can be lengthened by:
telomerase
When cultured normal human cells were infected with a virus that carried the genes that coded for a subunit of telomerase:
the cells underwent more cell divisions than normal
Cancerous cells differ from noncancerous cells in that cancerous cells:
can maintain telomere length as they divide
Mismatch repair occurs when
enzymes remove incorrectly-paired nucleotides