Explain how the structure of DNA is related to its functions (6 marks) - ANSWER - sugar-phosphate (backbonedouble stranded/helix so provides strength/stability/protects bases/protects hydrogen bonds - long/large molecule so can store lots of information - helix/coiled so compact - base sequence allows information to be stored/ base sequence codes for amino acids/protein - double stranded so replication can occur semi-conservatively/strands can act as templates/complementary base pairing/A-T and G-C so accurate replication/identical copies can be made - (weak) hydrogen bonds for replication/ unzipping/ strand separation/ many hydrogen bonds so stable/strong
Papaya plants reproduce sexually by means of seeds. Papaya plants grown from seeds are very variable in their yield. Explain why. (2 marks) - ANSWER - meiosis/independent assortment/crossing over - (fusion of) genetically different gametes/random fertilisation
3 documenten
|73 pagina's
Suggest the advantages of the change in blood flow in blood vessels during exercise. [3 marks] - ANSWER -more blood flow to muscles during exercise -supplying more glucose and oxygen/ removing carbon dioxide/ lactic acid/ heat -for high rate of respiration/ t...
Give one similarity and one difference between a taxis and a tropism (2 marks) - ANSWER 1. similarity - directional response (to stimulusmovement towards/away from a stimulus 2. difference - taxis (whole) organism moves and tropism a growth (response) Sc...
Explain how the structure of DNA is related to its functions (6 marks) - ANSWER - sugar-phosphate (backbone)/double stranded/helix so provides strength/stability/protects bases/protects hydrogen bonds - long/large molecule so can store lots of information - h...