Factors affecting enzyme activity

Question 1

What is meant by an endotherm?

Answer 1

An organism that relies on it’s metabolic processes to warm their bodies and maintain their own temperature.

Question 2

What are the four factors that affect enzyme activity?

Answer 2

• temperature
• pH
• enzyme conc.
• substrate conc.

Question 3

What is the effect of temperature on enzyme activity?

Answer 3

As temperature increases, molecular kinetic energy increases. Molecules move faster, leading to more successful collisions and more frequent ESC formations.

This continues up until the temperature reaches the enzyme’s optimum temperature.

Question 4

What happens once temperature exceeds the enzyme’s optimum temp?

Answer 4

The enzyme begins to be disrupted and lose stability:
- movement of the molecules continues to increase, causing them to vibrate which can break the weak hydrogen and ionic bonds in the tertiary structure.

This disrupts the active site, causing denaturation.

Question 5

In what context is denaturation reversible?

Answer 5

Thermal denaturation is usually irreversible, denaturation by pH can often be reversed.

Question 6

Define optimum temperature:

Answer 6

The temperature at which the rate of reaction is at it’ maximum. It varies according to the habitat to which an organism is adapted.

Question 7

What is meant by thermostable?

Answer 7

Organisms that have an optimum temperature of over 80°C.

Question 8

What is the temperature coefficient (Q10)?

Answer 8

The ratio between the activities of a process at two different temperatures.

For most enzyme-catalysed reactions, rate of reaction doubles for every 10°C increase. Temperature coefficient shows how much rate changes when temp is raised by 10°C.

Question 9

What is the equation for temperature coefficient?

Answer 9

temperature coefficient = rate of reaction at (x+10)°C / rate of reaction at x°C