Draw a labelled diagram of the digestive system.

Many people cannot digest lactose and benefit from a diet containing no lactose. Outline the production of lactose-free milk.

Explain how the kidney helps to retain useful substances in the blood and eliminate substances which the body does not need.

Award [1] each for the following structures clearly drawn and correctly labelled.
esophagus – connected to top of stomach;
stomach – connected to small intestine;
small and large intestines – connected to each other;
liver shown as larger than the stomach with gall bladder shown under/embedded in liver;
gall bladder – connected to the small intestine (via bile duct);
pancreas – connected to small intestine (via pancreatic duct);

milk contains lactose / lactose is milk sugar;
lactose is broken down to glucose and galactose;
by (the enzyme) lactase;
which is lacking in people with lactose intolerance;
lactose-free milk is sweeter than milk containing lactose;
lactase produced by small intestine / produced by yeast sometimes found in milk;
can be added directly to milk;
immobilized in beads / biotechnological techniques;
ultrafiltration of milk to remove lactose;

ultrafiltration occurs in the glomerulus;
basement membrane acts as a filter;
preventing proteins/cells from passing;
(filtered) substances pass to the Bowman’s capsule;
to proximal convoluted tubule (PCT);
(where there is) selective reabsorption;
(in PCT) all glucose/amino acids are reabsorbed;
(in PCT most) water reabsorbed;
surrounding the loop of Henle, is an area of high solute concentration;
in distal convoluted tubule, ions are exchanged between filtrate and blood;
collecting duct has role in osmoregulation;
ADH regulates the amount of water reabsorbed;
substances not reabsorbed are eliminated as urine;

The examiners do realise that they are not testing artistic ability. However all diagrams should be large enough and clear enough to show the connections between the parts. In addition, as the papers are now scanned, the lines should be bold, as should the labelling arrows. Marks were lost for not clearly showing that the oesophagus connected to the stomach, the stomach connected to the small intestine and the small intestine to the large. The location of the connection between the large and small intestine was not well known. The pancreas seemed to float around without any duct leading to the small intestine as did the liver and gall bladder. The liver was often drawn too small.

Most students were quite knowledgeable about lactose intolerance though there were a lot of misspelled words as well as incorrectly applied terms.

The knowledge of the workings of the kidney seemed to be very school-specific, with whole schools seeming to know little more than there is some filtering at the start and urine is produced in the end. Well-prepared candidates produced some impeccable answers.