2.4. 1 Enzymes

Question 1

Active Site:

Answer 1

Intended area on the surface of an enzyme molecule with a shape that is complementary to the shape of the substrate molecule

Question 2

Catalyst

Answer 2

chemical that speeds up the rate of a reaction and remains unchanged and reusable at the end of the reaction.

Question 3

Extracelluar

Answer 3

outside of the cell

Question 4

Intracellular

Answer 4

inside of the cell

Question 5

Product

Answer 5

molecule produced from substrate molecule, by an enzyme-catalysed reaction

Question 6

substrate

Answer 6

molecule that is altered by an enzyme catalyzed reaction

Question 7

Why are enzymes remarkable?

Answer 7

1. Enzymes are more specific than chemical catalysts. They do not produce unwanted by-products and rarely make mistakes.
2. Cells in which they are made can also regulate their production and activity to fit the needs of the cell or organisms at the time.

Question 8

Enzyme structure determines function

Answer 8

1. For enzymes to catalyse some reactions they may need help from some Cofactors
2. Instructions for making enzymes are encoded in genes. If the gene has a mutation that alters the sequence of amino acids in the protein, then this may alter the enzyme’s tertiary structure and prevent it from functioning
3. If an enzyme that catalyses a metabolic reaction is deficient then a metabolic disorder results
4. Enzymes also catalyse the formation of the organism;s structural components such as collagen in bones, cartilages.

Question 9

Catabolic

Answer 9

metabolites are broken down to smaller metabolites

Question 10

What are metabolites?

Answer 10

Reactants, intermediates, products

Question 11

What are anabolic pathways

Answer 11

energy is used to synthesise large molecules

Question 12

What does catalase consist of

Answer 12

Four polypeptide chains and contains a haem group with iron.

• Fastest acting enzyme, having the highest turnover
• Eukaroytic cells, catalase is found inside small vesicles called peroxisomes
• When white blood cells ingest pathogens they use catalase to help kill invading microbes

Question 13

Amylase

Answer 13

1. Salivary glands and acts in the mouth to digest the polysaccharide starch to the diasccahride maltose.

Question 14

What is a Cofactor

Answer 14

1. a substance that has to be present to ensure that an enzyme-catalysed reaction takes place at the appropriate rate.
2. A cofactor that is permanently bound, by covalent bond is called a prosthetic group

Question 15

Example of a Cofactor

Answer 15

• Carbonic anhydrase contains a zinc ion permanently bound.

- Found in erythrocytes and catalyses the interconversion of co2 and water to carbonic acid

Question 16

Induced fit hypthoseis

Answer 16

1. Enzyme specificity
2. When substrate molecules fit into the enzymes active site, the active site changes shape slightly to mould itself around the substrate molecule.
3. The active site is still complementary to the shape of the molecule but when binding, there is a subtle change of shape of the side chains that give the active site more conformation.
4. Moulding enables the substrate to bind more effectively to the site
5. Non covalent forces
   5.