SPEC POINT 2.5

Question 1

What are nucleotides in DNA and RNA made from?

Answer 1

1. pentose sugar
2. nitrogen containing organic base
3. phosphate group

Question 2

What are the components of an RNA nucleotide?

Answer 2

Ribose sugar with a hydroxyl (OH) group at the 2’ position
Phosphate group
Organic base from A U C or G

Question 2

What are the components of a DNA nucleotide?

Answer 2

Deoxyribose sugar with hydrogen at the 2’ position
Phosphate group
Organic bases A T C or G

Question 3

Which bases are purines, and what does this mean?

Answer 3

Purine = double ringed structure

A and G

Question 4

Which bases are pyrimidines, and what does this mean?

Answer 4

Pyrimidine = single ring structure

C, U and T

Question 5

What type of bonds join nucleotides in DNA and RNA?

Answer 5

Phosphodiester bonds

Question 6

How are phosphodiester bonds formed?

Answer 6

When separate nucleotides are joined by condensation reactions occurring between the phosphate group of one nucleotide and the pentose sugar of another. This creates a sugar-pentose backbone in DNA and RNA

Question 7

What is the structure of DNA?

Answer 7

Double helix structure

Question 8

Why is DNA antiparallel?

Answer 8

It is made up of 2 polynucleotides running in opposite directions

Question 9

How do the bases pair in DNA?

Answer 9

Purine A with pyrimidine T (2 H bonds)
Purine G with pyrimidine C (3 H bonds)
Hydrogen bonds form between complementary bases

Question 10

What is the difference between RNA and DNA?

Answer 10

RNA is only made up of 1 polynucleotide strand, whereas DNA is made up of 2
RNA = ribose sugar, DNA = deoxyribose sugar
RNA is relatively short compared to DNA