DNA Structure

Question 1

What is DNA?

Answer 1

It’s a store of genetic information

Question 2

What form is DNA present in nucleus?

Answer 2

It’s present as a chromatin

Question 3

What can damage DNA?

Answer 3

Radiation, chemicals

Question 4

What are 3 different forms of DNA?

Answer 4

A form, B form + Z form

Question 5

What are 2 helical forms of DNA?

Answer 5

A form + B form

Question 6

What is difference between the 3 different forms of DNA?

Answer 6

A form= major groove + minor groove are similar in size, 11 base pairs + right handed helix
B form= 10 base pairs, right handed helix
Z form= left handed helix

Question 7

Describe the structure of DNA?

Answer 7

Repeating sugar phosphate base units are linked by 3’-5’ phosphodiester bonds
Each strand has polarity—there is 5’ + 3’ ends
2 strands of DNA are antiparallel
DNA is negatively charged
DNA is acidic

Question 8

What are base pairs of DNA?

How many H bonds forms each base pair?

Answer 8

Cytosine + guanine => 3 H bonds which form base pairs

Adenine + thymine => 2 H bonds which form base pairs

Question 9

What is a pyrimidine?

Answer 9

One 6-membered ring of carbon + nitrogen atoms

Members of pyrimidine family are Cytosine, thymine + uracil

Question 10

What is purine ?

Answer 10

Larger than pyrimidine

6- membered ring fused to a 5-membered ring

Question 11

What is importance of DNA repair?

Answer 11

Maintains genome stability