BIO 111- Test 8- DNA
If a double-stranded DNA has 15 thymines, how many adenines will it have?
15
Adenine and Thymine are held together by ________ hydrogen bonds.
2
If cytosine makes up 22% of the nucleotides in a sample of DNA from an organism, then adenine would make up what percent of the bases?
28%
A segment of DNA has one strand with the following sequence of bases: 3' - AGCGCATAGCAA - 5'. What would be the base sequence of a complementary strand of DNA?
5' - TCGCGTATCGTT - 3'
Suppose that you provide an actively dividing culture of E. coli bacteria with radioactive thymine. What would you expect to happen if a cell replicated its DNA and divided with the radioactive base?
DNA in both new cells would be radioactive.
Which of the following is the best definition of semiconservative replication?
The fact that a DNA molecule consists of one parental (old) strand and one new strand
The following represents a correct pairing of nitrogen bases
adenine; thymine
Which enzyme catalyzes the elongation of a DNA strand in the 5' to 3' direction?
dna polymerase
DNA is a molecule composed of a single strand of nucleotides.
false
Which enzyme is used first in replication to unwind and unzip the DNA?
helicase
Which enzyme unwinds and unzips the DNA?
helicase
When the DNA forms a chromosome, it coils around
histones
Which type of bond holds nitrogen bases together?
hydrogen
Any change in the sequence of nitrogen bases is called a __________.
mutation
Which enzyme checks the new DNA strand for mistakes?
polymerase
A 3' end of DNA would have a free
sugar
After DNA replicates. the two new strands form a double-stranded chromosome.
true
Name one scientist that is credited with the discovery of the DNA molecule.
Watson, crick, franklin, wilkins
The best description of a DNA molecule is
a double helix with sugar-phosphate sides and the nitrogenous bases in the center
Which of the following descriptions best fits the class of molecules known as nucleotides?
a nitrogenous base, a phosphate group, and a five-carbon sugar
