Test 8 Biology

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%

DNA having the sequence 3' ATAGGC 5" is complementary to the sequence

5' TATCCG 3'

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 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

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

When DNA replicates, it makes a(n) _________ copy of itself.

identical

Which enzyme attaches nucleotides together?

ligase

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

The following represents a correct pairing of nitrogen bases

adenine : thymine

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