2.2.2 - DNA: Structure

Question 1

What Does DNA Stand For?

Answer 1

Deoxyribonucleic acid.

Question 2

What Is The Function Of DNA?

Answer 2

Stores genetic information.

Question 3

What Is DNA?

Answer 3

Polynucleotide.

Question 4

Describe The Structure Of A DNA Mononucleotide
(3 Points)

Answer 4

~ Pentose sugar is deoxyribose.

~ Each DNA mononucleotide has the same sugar and phosphate group.

~ A -> T, C -> G.

Question 5

What Are DNA Molecules Made Up Of?
(2 Points)

Answer 5

~ 2 Polynucleotide strands lying side by side, running in opposite directions

~ The strands are said to be antiparallel.

Question 6

Describe How The Sugar-Phosphate Backbone Is Formed
(5 Points)

Answer 6

~ Each DNA polynucleotide strand is made up of alternating deoxyribose sugars and phosphate groups bonded together to form the sugar-phosphate backbone.

~ The bonds are known as phosphodiester bonds.

~ The phosphodiester bonds link the 5-carbon of one deoxyribose sugar molecule to phosphate group from the same nucleotide, which itself is linked by another phosphodiester bond bond to the 3-carbon of the deoxyribose sugar molecule of the next nucleotide in the strand.

~ Each DNA polynucleotide strand is said to have a 3’ end and a 5’ end.

~ As the strands run in opposite directions they are antiparallel, on is known as the 5’ to 3’ strand and the other is known as the 3’ to 5’ strand.

Question 7

Describe How The 2 DNA Polynucleotides Chains Into A Double Helix
(4 Points)

Answer 7

~ 2 DNA polynucleotide strands join together by hydrogen bonding between the bases.

~ 2 hydrogen bonds are between A -> T.

~ 3 hydrogen bonds are between C -> G.

~ 2 antiparallel polynucleotides strands twist to form the double helix.