Nucleic acids

Question 1

What do DNA and RNA carry?

Answer 1

Genetic information

Question 2

What are ribosomes made up of?

Answer 2

RNA and proteins

Question 3

Structure of a nucleotide

Answer 3

A pentose sugar
A nitrogen-containing base
A phosphate group

Question 4

Type of bond that forms between nucleotides.

Answer 4

Phosphodiester bonds

Question 5

Structure of DNA

Answer 5

A DNA molecule is a double helix composed of two polynucleotides joined together by hydrogen bonds between complementary bases.

Question 6

Structure of RNA

Answer 6

RNA is a relatively short polynucleotide chain.

Question 7

How is DNA stable?

Answer 7

The phosphodiester backbone protects the more chemically reactive nitrogen-containing
organic bases inside the double helix.

Hydrogen bond form bridges between the phosphodiester uprights.

As there are three hydrogen bonds between G and C, rather than two for A and T, a higher proportion of C—G pairings makes DNA more stable.

Question 8

Semi Conservative replication

Answer 8

DNA helicase breaks the hydrogen bonds between the complentary bases to make two single strands.

One of the strands is used as the template and complementary base pairing occurs between the template strand and free nucleotides.

The nucleotides of the new strands are joined together via condensation reactions and catalysed with DNA polymerase.

The result is that two identical strands of DNA are formed.