DNA Structures

Question 1

Purines

Answer 1

N

Question 2

Pyrimidines

Answer 2

Nitrogenous bases with one ring: Cytosine (C) and Thymine (T)

Question 3

Base Pairing Rules

Answer 3

A-T with 2 hydrogen bonds, C-G with 3 hydrogen bonds

Question 4

Antiparallel

Answer 4

The two strands of DNA run in opposite directions (5’→3’ and 3’→5’)

Question 5

B-DNA

Answer 5

The most common right-handed double helix form of DNA

Question 6

DNA Polymerase III

Answer 6

Adds nucleotides to the new DNA strand in the 5’→3’ direction

Question 7

Helicase

Answer 7

Unwinds and separates the DNA strands

Question 8

SSBs

Answer 8

Single-strand binding proteins that stabilize open DNA strands

Question 9

Primase

Answer 9

Adds RNA primers to initiate DNA synthesis

Question 10

Ligase

Answer 10

Seals gaps between Okazaki fragments on the lagging strand

Question 11

Leading Strand

Answer 11

Synthesized continuously in the 5’→3’ direction

Question 12

Lagging Strand

Answer 12

Synthesized in short segments called Okazaki fragments

Question 13

Semiconservative Replication

Answer 13

Each new DNA molecule has one old strand and one new strand

Question 14

Phosphodiester Bond

Answer 14

Link between the 3’ OH and 5’ phosphate of nucleotides

Question 15

Direction of Synthesis

Answer 15

DNA is synthesized in the 5’→3’ direction