Effects of substrate concentration and temperature on rate of enzyme activity | Biology

Starter quiz

What type of molecule are enzymes?

proteins ✓

lipids

carbohydrates

amino acids
True or false? Enzymes can affect the rate of a reaction.

True ✓

False
Enzymes ______ the amount of activation energy needed for a reaction to take place.

'lower' ✓
What region on an enzyme does the substrate bind to?

substrate site

active site ✓

complex site

enzyme substrate complex site
What can be said about the shape of the active site and the substrate shape?

they are the same

they are complementary ✓

the substrate is like a lock and the enzyme is like a key
Put the steps in order to show how an enzyme works.

1

⇔

the substrate and enzyme collide

2

⇔

the substrate binds to the enzyme

3

⇔

an enzyme substrate complex forms

4

⇔

a chemical reaction takes place

5

⇔

the product(s) are released

6

⇔

the enzyme is free to catalyse another reaction

True or false? The concentration of substrate will affect the rate of reaction.

True ✓

False
At high temperatures the shape of the enzyme's active site can change, and it no longer fits the substrate. We say the enzyme has become ...

denatured ✓

energised

unbonded

denaturalised
Match the labels to what is happening.

a- At low temperatures

⇔

there are fewer successful collisions so the reaction rate is lower. ✓

b- At the optimum temperature

⇔

all active sites are full and reaction rate is as high as it can be. ✓

c- At high tmeperatures

⇔

the enzyme is denatured. The reaction cannot be catalysed. ✓
Which part of an enzyme does the substrate need to collide with for a reaction to take place?

'active site' ✓
What is the rate of reaction?

how much substrate has been used up

how much substrate has not been used up

how long it took for the reaction to finish

how much product is formed per unit of time ✓
Below are two graphs showing the rates of enzyme facilitated reactions. Match the graph to the factor affecting the rate of reaction.

Temperature

⇔

Graph B ✓

Concentration of substrate

⇔

Graph A ✓

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The rate of a reaction is the amount of change (e.g. substrate broken down or product made) per unit of time.
Enzyme reaction rate increases as substrate concentration increases, until an optimum when all active sites are full.
Enzyme reaction rate increases with temperature due to more collisions, until an optimum when all active sites are full.
Enzyme reaction rate decreases as temperature increases above the optimum, as the active site becomes denatured.
Interpretation of graphs showing effects of substrate concentration and temperature on enzyme reaction rate.

Enzymes die rather than denature.

The word denature is clearly introduced and a CfU explores the word die vs denature.

Rate of reaction - A measure of how much change occurs per unit of time.
Concentration - A measure of the quantity of a dissolved substance in a given volume of solution.
Optimum - The conditions where maximum rate of reaction occurs.
Denatured - A permanent change in the shape of an enzyme which stops it from working.