DNA & RNA structure

Question 1

List the components of DNA (3)

Answer 1

1. deoxyribose (pentose sugar)
2. Phosphate group
3. Nitrogenous base: A, T, G, C

Question 2

List the components of RNA (3)

Answer 2

1. Ribose (pentose sugar)
2. Phosphate group
3. Nitrogenous base: A, U, C, G

Question 3

Explain why DNA is a stable molecule (3)

Answer 3

1. Phosphodiester backbone protects the more chemically reactive bases inside the double helix
2. Hydrogen bonds form bridges between bases.
3. C-G has 3 hydrogen bonds and A-T has 2. So, a higher proportion of C-G bases to A-T bases, the more stable a DNA molecule is

Question 4

Explain how DNA is adapted to its function (5)

Answer 4

1. DNA functions as a hereditary material responsible for passing genetic information from cell to cell and generation to generation
2. It is a very stable structure that usually passes from cell to cell without significant change - phosphodiester backbone protects more reactive bases from chemical and physical forces to some extent
3. Two strands (bases) are joined only by hydrogen bonds, so they can separate for DNA replication and protein synthesis
4. Extremely large molecule with multiple sequencing that can carry immense amounts of genetic information
5. Base pairing allows DNA to replicate and transfer information via mRNA