Enzymes

Question 1

State and explain the 3 characteristics of enzymes.

Answer 1

1) Act as biological catalysts

2) Reduce need for high temperatures. Used in metabolic reactions

3) They’re proteins, made from chains of amino acids

Question 2

What is a catalyst?

Answer 2

= Substance that increases speed of reaction without being changed or used up

Question 3

What are chemical reactions?

Answer 3

involve something being split up or joined together

Question 4

What is a Substrate?

Answer 4

= molecule changed in reaction

Question 5

Explain the ‘lock and key’ model

Answer 5

1) Every enzyme molecule has a active site. Part where substrate joins to enzyme.

2) Enzymes speed up 1 reaction, as substrate has to be correct shape to fit active site.

3) Called ‘lock and key’ model.

Question 6

Explain how temperature can affect enzyme activity

Answer 6

1) Changing temperature changes rate of enzyme-catalysed reaction

2) High temperature increases rate. Enzyme & substrate have more energy, more likely to collide to form enzyme-substrate complexes

3) But if too hot, some bonds holding enzyme together break. Changes shape of enzymes active site, so substrate can’t fit. Enzyme becomes denatured

4) All enzymes have a optimum temperature

Question 7

State how PH can affect enzyme activity

Answer 7

1) If PH too high or low it interferes with bonds holdings enzyme together. Changes shape of active site, denaturing the enzyme

2) Optimum PH usually 7