Transport is the function of the protein known as hemoglobin. State the name and function of another protein. Do not use enzymes or membrane proteins for your answer.

Name:  .............................................................
Function:  .............................................................

Explain the role of enzymes in metabolic pathways.

Describe how the link reaction and the Krebs cycle are related.

name of protein;
function of protein;
(both needed)

a. enzymes speed up/catalyse metabolic reactions;
b. by reducing the activation energy;
c. each reaction (in the pathway) has a different enzyme;
d. metabolic pathways can be controlled by controlling which enzymes are produced;
e. end-products of a metabolic pathway act as inhibitors;
f. end-product inhibitors bind to/inhibit an enzyme at the start of the pathway;

a. the link reaction produces acetyl CoA/acetyl group/CH₃CO;
b. acetyl group/CH₃CO joins with 4 carbon compound/OAA from cycle;
c. both occur in the (mitochondrial) matrix;

In (a) naming a protein and its use should have been an easy mark. Unfortunately it was very poorly answered.

In b most knew the function of enzymes and their reduction of the activation energy. However, only the better candidates gained the other marks by correctly putting them into the context of pathways.

 In c the production of Acetyl CoA from the link reaction was well understood. Unfortunately its destiny was less well known.