Enzymes

Question 1

What are enzymes?

Answer 1

biological/ made by cells ;
catalyst/ speeds up the rate of a reaction ;
made of protein ;

Question 2

How enzymes catalyse chemical reactions?

Answer 2

lock and key mechanism;
substrate fits into enzyme;
(shape of) substrate is complementary to, enzyme/active site;
ref to active site;
substrate breaks/product(s) forms/product(s) leaves enzyme;
enzyme, free for next reaction/not used up/remains unchanged;

Question 3

Why enzymes are necessary for biological processes?

Answer 3

without enzymes reactions, occur too slowly / not at all ;
A enzymes speed up reactions
reduce, activation energy / energy needed for a reaction ;
reactions take place at lower temperatures ;
enzymes are catalysts

Question 4

Explain lock and key hypothesis?

Answer 4

substrate, ‘fits’ into enzyme ;
active site (of enzyme);
shape is complementary ;
substrate is key, enzyme is lock ;
substrate / starch / nutrient, converted (into products) / AW ;
(2) products (molecules) lea ;
enzyme / amylase, can work again on another substrate ;

Question 5

Describe how enzymes in root cells synthesise starch?

Answer 5

substrate, ‘fits’ into enzyme ;
active site (of enzyme);
shape is complementary ;
substrate is key, enzyme is lock ;
substrate / starch / nutrient, converted (into products) / AW ;
(2) products (molecules) lea ;
enzyme / amylase, can work again on another substrate ;

Question 6

Effect of increasing temp. on enzyme activity?

Answer 6

increase in (kinetic) energy ;
more, collisions / AW ;
between, enzyme / active site, and, substrate / AW ;
ref. to optimum temperature / works best at ≈ 30 oC ;
denatured, at high temperature / above 30 oC / above
optimum ;

Question 7

Explain how enzymes in biological washing powders act to remove food and blood
stains from clothes?

Answer 7

protein digested to, amino acids / (poly)peptides ; A broken down /
hydrolysed
(by) protease(s) ;
fats digested to fatty acids (and glycerol) ;
(by) lipase(s) ; R ligase
(by) amylase ;
starch to, sugar, maltose, glucose ;
(by) cellulase ;
breaksdown cellulose (fibres) to release stains ; A reduces p