Genetic information,variation and relationships between organisms

Question 1

Messenger RNA (mRNA) is used during translation to form polypeptides. Describe how mRNA is produced in the nucleus of a cell.

Answer 1

Helicase;
Breaks hydrogen bonds;
Only one DNA strand acts as template;
RNA nucleotides attracted to exposed bases; (Attraction) according to base pairing rule;
RNA polymerase joins (RNA) nucleotides together; Pre-mRNA spliced to remove introns.

Question 2

Describe how proteins are digested in the human gut.

Answer 2

Hydrolysis of peptide bonds;
Endopeptidases break polypeptides into smaller peptide chains; Exopeptidases remove terminal amino acids;
Dipeptidases hydrolyse / break down dipeptides into amino acids.

Question 3

Describe the structure of proteins.

Answer 3

Polymer of amino acids;
Joined by peptide bonds;
Formed by condensation;
Primary structure is order of amino acids;
Secondary structure is folding of polypeptide chain due to hydrogen bonding;
Accept alpha helix / pleated sheet
Tertiary structure is 3-D folding due to hydrogen bonding and ionic / disulfide bonds;
Quaternary structure is two or more polypeptide chains.