IB Biology Topic C1.1.8 Effects of Temperature, Ph and Substrate Concentration on the Rate of Enzyme Activity Revision Notes (SL/HL)

IB Biology Topic C1.1.8 Effects of Temperature, Ph and Substrate Concentration on the Rate of Enzyme Activity Revision Notes (SL/HL) | RevisionDojo

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Temperature, pH and Substrate Concentration Each Shape the Rate of Enzyme Activity

Three variables have a strong effect on the rate of an enzyme-catalysed reaction: temperature, pH and substrate concentration.
Each one changes the rate in its own pattern, shown by a characteristic graph.

Temperature: Rate Rises to an Optimum, Then Falls

As temperature rises, enzyme and substrate gain kinetic energy and move faster.
They collide more often, so more successful enzyme-substrate collisions happen and the rate goes up.
The rate is highest at the optimum temperature.

Tip

As a rough guide, the rate roughly doubles for each 10°C rise, up to the optimum.

Why the Rate Falls Above the Optimum

Above the optimum, the enzyme begins to denature, so its active site changes shape.
The substrate no longer fits, so the rate drops steeply.

Note

Denaturation is covered in detail in C1.1.7.
Here the key point is that it explains the falling side of the temperature curve.

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Temperature, pH and Substrate Concentration Each Shape the Rate of Enzyme Activity

Three variables have a strong effect on the rate of an enzyme-catalysed reaction: temperature, pH and substrate concentration.
Each one changes the rate in its own pattern, shown by a characteristic graph.

Temperature: Rate Rises to an Optimum, Then Falls

As temperature rises, enzyme and substrate gain kinetic energy and move faster.
They collide more often, so more successful enzyme-substrate collisions happen and the rate goes up.
The rate is highest at the optimum temperature.

Tip

As a rough guide, the rate roughly doubles for each 10°C rise, up to the optimum.

Why the Rate Falls Above the Optimum

Above the optimum, the enzyme begins to denature, so its active site changes shape.
The substrate no longer fits, so the rate drops steeply.

Note

Denaturation is covered in detail in C1.1.7.
Here the key point is that it explains the falling side of the temperature curve.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics

IB Biology Topic C1.1.8: Effects of Temperature, Ph and Substrate Concentration on the Rate of Enzyme Activity Notes

Temperature, pH and Substrate Concentration Each Shape the Rate of Enzyme Activity

Temperature: Rate Rises to an Optimum, Then Falls

Why the Rate Falls Above the Optimum

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Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

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Temperature, pH and Substrate Concentration Each Shape the Rate of Enzyme Activity

Temperature: Rate Rises to an Optimum, Then Falls

Why the Rate Falls Above the Optimum

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

A - Unity and Diversity9 subtopics

B - Form and Function10 subtopics

C - Interaction and Interdependence9 subtopics

D - Continuity and Change12 subtopics