Draw a labelled diagram to show the structure of a membrane.

Outline how vesicles are used to transport materials secreted by a cell.

Explain how the structure of a villus in the small intestine is related to its function.

Award [1] for each of the following clearly drawn and correctly labelled.
phospholipid bilayer – double row of opposing phospholipids, tails to inside;
phospholipid – with head and two tails;
hydrophilic/phosphate/polar (heads) and hydrophobic/hydrocarbon/fatty acid/non-polar (tails) labelled;
integral protein – embedded in the phospholipid bilayer;
protein channel – integral protein showing clear channel/pore;
peripheral protein – on the surface;
glycoprotein – with carbohydrate attached on one side;
cholesterol – shown embedded in bilayer;

vesicles formed from rER transport proteins to Golgi apparatus;
these vesicles fuse with membranes of Golgi apparatus;
proteins are processed as they move through Golgi apparatus;
(transport) vesicles bud off/leave Golgi apparatus;
vesicles move through cytoplasm;
(vesicles) fuse with plasma membrane;
contents released to outside of cell / exocytosis;
cells use vesicles to secrete substances such as hormones/digestive enzymes/other appropriate example;
vesicles may contain cell products other than proteins;
Credit drawings which fully explain the points above.

To achieve [1] answer must name the structure and relate it to its function.
the villus has a large surface area to volume ratio;
microvilli increase surface area for absorption;
thin surface (epithelial) layer so products of digestion can pass easily through;
channel proteins located in plasma membrane used for facilitated diffusion;
network of capillaries inside each villus (so only short distance) for movement of absorbed products;
capillaries transport absorbed nutrients/sugars and amino acids away from small intestine;
blood flow in capillaries maintains concentration gradient;
central lymph vessel/lacteal to transport absorbed fats/fatty acids away from small intestine;
large number of mitochondria provide ATP needed for active transport;
protein pumps in membrane (of microvilli) carry out active transport;
pinocytosis occurs at surface (epithelial) layer;
Accept any of the points above shown in a drawing.

Many good membrane diagrams were seen. Phospholipids usually were shown with two tails. There was some uncertainty about the appearance of glycoproteins.

There were a variety of confused answers written about vesicles transporting materials produced by the cell.  Some candidates mistakenly began with endocytosis and the formation of vesicles as the plasma membrane pinched inwardly.  Only a few candidates stated that vesicles formed from rER and that proteins were carried to the Golgi apparatus.  

Many candidates eventually stated that vesicles fuse with the plasma membrane but some thought that the vesicles again form around the cell product to transport materials outside the cell.  Generally, candidates did not know this topic.   

Candidates knew that villi increase the intestinal surface area for greater absorption. They also knew that the thinness of the villi surface layer facilitates the passage of digestive products into the villi. Explanations usually included the role of capillaries but less often the role of lacteals. There was little mention of mitochondria, ATP, protein pumps or active transport. A few candidates mistakenly thought that villi help pass food along the digestive tract.