Nucleic acids

Question 1

What is the structure of DNA?

Answer 1

Double Helix formed by two strands of nucleotides
Each nucleotide composed of a deoxyribose sugar, a phosphate group and a nitrogenous base (A,C,T,G)

Question 2

What is the structure of RNA?

Answer 2

Single stranded molecule made up of long chain of nuclotides
Each nucleotide contains a ribose sugar, phosphate group and nitrogenous base (A,C,G,U)

Question 3

What is the difference between RNA and DNA?

Answer 3

• DNA double stranded, RNA single stranded
• DNA has deoxyribose sugar, RNA has ribose sugar
• DNA has base T, RNA has base U

Question 4

What is the structure of a ribose sugar?

Answer 4

Pentose sugar

Question 5

What is the structure of deoxyribose sugar?

Answer 5

Pentose sugar
(doesn’t have 2’ hydroxyl group comapred to ribose)

Question 6

What is the difference between purines and pyrimidines structurally?

Answer 6

Purines:
2 ring structure (one 6 membered, one 5)
(larger + more bulky)
Pyramidines:
Single 6 membered ring

Question 7

Which bases are purines?

Answer 7

Guanine
Adenine

Question 8

Which bases are pyrmadines?

Answer 8

Cytosine
Thymine
Uracil

Question 9

What enzymes break down nucleic acids?

Answer 9

Nucleases

Question 10

What is the difference between purines and pyrimidines functionally?

Answer 10

Purines has more diverse functions
e.g cAMP (adenine), G proteins (guanine), ATP

Question 11

Why are GC regions more stable and AT?

Answer 11

AT pairs form 2 hydrogen bonds
GC pairs form 3 hydrogen bonds
-> stronger bonds -> higher melting temperature