3.1.4.3 Proteins - Factors Affecting Enzyme Action Flashcards Preview

SHHS - Science - NEW AQA A-Level Biology (Year 1) > 3.1.4.3 Proteins - Factors Affecting Enzyme Action > Flashcards

Flashcards in 3.1.4.3 Proteins - Factors Affecting Enzyme Action Deck (20):
1

For an enzyme to work it must:

come into contact with its substrate.

have an active site which complements the substrate.

2

How can the progress of an enzyme controlled reaction be measured? (2 methods)

measure the amount of product produced over time.

measure substrate disappearance over time..

3

Explain the initial rate of reaction shown in the graph

Q image thumb

Lots of substrate, no product.

Easy for substrate molecules to come into contact with enzyme.

All enzyme active sites filled with substrate so product rapidly produced.

 

 

4

Explain the rate of reaction shown in the graph after 1 minute

Q image thumb

Less substrate now so less product being produced.

More difficult for substrate to come into contact with active sites of enzyme

The graph eventually flattens because there is no substrate left to act on.

 

5

Explain the initial drop in starch shown in the graph below

Q image thumb

Lots of substrate, no product to get in way

Easy for substrate molecules to come into contact with enzyme.

All enzyme active sites filled with substrate so substrate rapidly reduced.

6

Explain the drop in starch shown in the graph below after 3 minutes

Q image thumb

Less substrate now and more product to get in the way.

More difficult for substrate to come into contact with active sites of enzyme

The graph eventually flattens because there is no substrate left to act on.

7

How would you calculate the rate of reaction at the red point?

Q image thumb

Draw a straight line against the point (a tangent line)

The rate of reaction is equal to the gradient of this line.

Gradient = change in Y / change in X

 

A image thumb
8

Explain the the change in reaction rate between 0-40 Degrees Celsius shown in the graph below

Q image thumb

Higher temp, more kinetic energy given to enzymes and substrate

More successful collisions between enzymes and substrate

This is shown by the rising curve which reaches its peak at 40 DegC

9

Explain the the change in reaction rate after 40 Degrees Celsius shown in the graph below

Q image thumb

Hydrogen bonds in enzyme start to break due to high temp.

The enzyme and its active site begin to change chape, substrate fits less easily and reaction slows.

Enzyme eventually changes shape so much, it denatures. Enzyme can no longer bind to substrate so reaction ends.

 

10

Many of the enzymes in the body have an optimum temperature of 40 °C. Why has the body evolved to have a temperature of 37 °C?

Body needs to use more energy to maintain 40 °C

Other, non-enzyme, proteins in the body may denature at 40 °C

During illness body temperature would increase above 40 °C. This might denature the enzymes.

11

Why do birds have a body temperature of 40 °C?

They have a high metabolic rate in order to release the energy required for flight.

12

How can we calculate the gradient of a line on a line graph?

Gradient = Change in Y/Change in X

13

Draw a Tangent on the graph to show the rate of reaction at a specific point. Label the change in X "a" and change in Y "B"

Q image thumb

A image thumb
14

How can we calculate the rate of enzyme reaction at a specific point on a graph that shows the "amount of product formed" OR "substrate used" up the Y axis and "time" along the X axis.

Draw a tangent at this point and calculate its gradient.

Gradient = Change in Y/Change in X

15

A solution with a high H+ ion concentration is an...

acid

16

A solution with a high OH- concentration is an...

alkali

17

What is the equaiton for calculating the pH of a solution?

pH = -log10[H+]

18

What happens at pH's that are outside of an enzymes optimum pH range?

The enzyme will denature

19

Explain why an enzyme denatures at pH's outside of its optimum range.

Change in pH alters the amino acid charges in the active site so substrates can no longer bind.

The change in pH can cause the ionic and hydrogen bonds holding the teriary structure to break. This changes the shape of the active site.

20

Why are enzymes denatured faster at 60 degrees compared to 40 degrees?

More kinetic energy

bonds (ionic/hydrogen) between amino acids broken faster