2.1 Nucleic acids (RNA and DNA)

Question 1

What is the nucleotide structure?

Answer 1

• pentose sugar
• phosphate group
• organic nitrogenous base (A,T,G,C,U)

Question 2

What bond is formed between two mononucleotides?

Answer 2

phosphodiester bond

Question 3

What are the complementary base pairing rules?

Answer 3

Adenine can only bind toe Thymine
Guanine can only bind onto Cytosine
The percentage of the bases are equal, e.g. 24% Adenine means 24% Thymine

Question 4

Explain how the structure of DNA is related to its functions.

Answer 4

• double stranded; strength, stability, protects bases
• large/long molecule so can store lots of info
• helix/coiled, doesn’t take up much space
• base sequence allows information to be stored
• double stranded, so replication can be semi-conservative
• weak hydrogen bonds for strand separation/stable/strong

Question 5

What are the differences between DNA and RNA?

Answer 5

• DNA is double stranded whereas RNA is single stranded
• DNA’s 4 bases are A,T,G,C whereas RNA’s are A,U,G,C
• DNA has a deoxyribose sugar whereas RNA has a ribose