1.12 Enzymes

Question 1

Main idea

Answer 1

Enzymes are specific to their substrate and increase reaction rates by lowering activation energy

Question 2

Define enzyme

Answer 2

An enzyme is a globular protein functioning as a biological catalyst.

Question 3

Define active site

Answer 3

The site on the surface of an enzyme to which the substrate or substrates bind.

Question 4

Explain substrate specificity

Answer 4

An enzyme has an active site that only fits with specific substrates.

Question 5

Describe the induced fit model of enzyme substrate binding

Answer 5

The active site is not a rigid shape

its shape will change when the substrate binds to it

this makes the fit between the substrate and the enzyme very close

Question 6

How do enzymes increase reaction rates

Answer 6

by lowering activation energy

reactions require an initial input of energy to proceed called activation energy

enzymes lower the required activation energy to allow faster reactions at lower temperatures

Question 7

Enzymes lower required collision rate

Answer 7

all reactions either with or without enzymes need collisions between molecules to occur

many molecules have strong bonds holding them together so require powerful collisions at high speed to break these bonds

Question 8

Enzymes allow optimum reaction rate at body temperature

Answer 8

Increasing the rate of collision to a rate at which these reactions would occur would require prohibitive amounts of energy, usually in the form of heat.

Enzymes stress substrate bonds so that a weaker collision is required to break them, reducing the amount of energy needed to cause these reactions to occur.