| Date | May 2013 | Marks available | 2 | Reference code | 13M.2.HL.TZ1.2 |
| Level | Higher level | Paper | Paper 2 | Time zone | Time zone 1 |
| Command term | Describe | Question number | 2 | Adapted from | N/A |
Question
The diagram shows how vesicles are used to transport materials in a cell.
State the name of organelle A.
State the process occurring at B.
Describe how the structure of the membrane allows the formation of vesicles.
Markscheme
Golgi apparatus/complex/body
Reject Golgi vesicle and Golgi unqualified.
endocytosis/phagocytosis/pinocytosis
Reject exocytosis.
fluidity of membrane allows change of shape/invagination/formation of vesicles;
phospholipids can move / phospholipid bilayer makes membrane fluid/flexible;
weak bonding between phospholipid tails;
bends/kinks in the phospholipid tails prevent close packing;
cholesterol affects membrane fluidity;
Examiners report
About half of the candidates identified the structure correctly as Golgi apparatus, with the others mostly suggesting rough endoplasmic reticulum even though there were no ribosomes on the outside.
Again about half of candidates answered correctly with endocytosis or a variant of this process. A wide range of other answers was given by other candidates.
This question was answered moderately well. Candidates were expected to link the fluidity of the phospholipid bilayer to the movement involved in vesicle formation.
