Chapter 4: 4.1 DNA Structure and Sequence

Question 1

Important features of DNA:

The structure of DNA is —— —–

Answer 1

Double helix

Question 2

Important features of DNA:

What is a DNA comprised of? (2)

Answer 2

1. Sugar-phosphate backbone
2. Nucleotide bases

Question 3

Important features of DNA:

Complementary strands are ————- to one another

Answer 3

Anti-parallel

Question 4

Important features of DNA:

What direction do the complementary strands run?

Answer 4

5’ to 3’

Question 5

Important features of DNA:

———- —– are connected by…

Answer 5

1. Nucleotide bases
2. Hydrogen bonds

Question 6

Important features of DNA:

What are the two nucleotide bases pairings?

Answer 6

1. Adenine (A) with Thymine (T)
2. Guanine (G) with Cytosine (C)

Question 7

Important features of DNA:

——- hydrogen bond with ———–

Answer 7

1. Purines
2. Pyrimidines

Question 8

Important features of DNA:

State the purines and pyrimidines

Answer 8

Purines:
* Adenine (A) and Guanine (G)

Pyrimidines:
* Thymine (T) and Cytosine (C)

Question 9

Important features of DNA:

In RNA, what replaces Thymine?

Answer 9

Uracyl (U)

Question 10

Important features of DNA:

Describe the bonding between purines and pyrimidines

Answer 10

1. Cytosine and Guanine have 3 hydrogen bonds
2. Adenine and Thymine have 2 hydrogen bonds

Question 11

True or False:

The bond between cytosine and guanine is easier to break

Answer 11

False, it is harder to break, requires more energy (higher temperature etc.)

Question 12

State:

Mnemonic for Pyrimidines

Answer 12

CUT the Py
* Cytosine, Uracil and Thymine are Pyrimidines

Question 13

State:

Mnemonic for Purines

Answer 13

Pure As Gold
* Purines are Adenine and Guanine

Question 14

How is the DNA backbone elongated?

Answer 14

Phosphodiester bonds form between the 3’ -OH group of one nucleoside to the 5’ phosphate group of an incoming nucleoside