1.5.1 nucleic acids: DNA & RNA

Question 1

Function of DNA & RNA

Answer 1

Deoxyribonucleic acid holds genetic information

Ribonucleic acid transfers genetic information from DNA to ribosomes

Ribosomes formed from RNA and proteins

Question 2

Nucleotides (monomers)

Answer 2

Contain pentose sugar, nitrogenous base, phosphate group

Make DNA or RNA which are nucleic acids (polymers)

Joined together by condensation reactions forming phosphodiester bonds

Question 3

DNA

Answer 3

2 strands joined in anti-parallel,

held together by hydrogen bonds between specific complementary base pairs, twisting into double helix

Question 4

RNA

Answer 4

Single RNA polynucleotide strand

Question 5

Differences between DNA and RNA nucleotides

Answer 5

DNA has pentose sugar deoxyribose, whereas RNA has pentose sugar ribose

DNA has base thymine, whereas RNA has uracil

Question 6

Differences between DNA and RNA molecules

Answer 6

DNA is double-stranded whereas RNA is single-stranded

DNA is longer whereas RNA is shorter

Question 7

Structure of DNA related to its function

Answer 7

Double stranded - both strands act as templates for semi-conservative replication

Weak hydrogen bonds between bases - can be unzipped for replication

Complementary base pairing - accurate replication

Many hydrogen bonds between bases - stable/strong molecule

Double helix with sugar phosphate backbone - protects bases/H bonds

Long molecule - stores lots of genetic information that codes for polypeptides

Double helix (coiled) - compact