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Analyse The Role of Enzymes

In this activity, students will analyse the function and production of enzymes, as well as the different conditions necessary for optimal enzyme action.

'Analyse The Role of Enzymes' worksheet

Key stage:  KS 4

GCSE Subjects:   Component 1: Concepts in Biology: Single Subject

GCSE Boards:   Eduqas

Curriculum topic:   Cell Biology

Curriculum subtopic:   Cell Metabolism

Difficulty level:  

Worksheet Overview

QUESTION 1 of 10

Without enzymes, we would never function!

 

Every chemical reaction our bodies need to survive- respiration, digestion, even thinking- all depend on fast reactions maintained by enzymes.

 

Both chemistry and biology are mad about enzymes, so let’s get going!

 

1. Question: Who are they?

Answer: Well, enzymes are actually a type of protein made by cells like stomach cells.


Reminder: A protein or polypeptide is a folded polymer with a specific sequence of amino acids.


This unique arrangement of amino acids exists in a chain, which then folds and is held in place by chemical bonds, giving a unique 3D shape.

 

For enzymes, the final structure always includes an area designed for a specific molecule called an active site, and the shape is always specific to its function, like an enzyme for insulin needs a different shape to an enzyme for starch.

 

2. Question: What do they do?

Answer: They are biological catalysts!


A catalyst speeds up reactions WITHOUT BEING USED UP


They are specifically designed for certain substances meaning every active site is a unique match to a certain ingredient ('reactants' in chemistry and 'substrates' in enzyme talk).

 

But remember- NO FIT = NO REACTION!

 

 

3. Question: How do they work?

Answer: THE LOCK AND KEY HYPOTHESIS:

a. The correct enzyme is present for the specific reaction, with its active site being the right fit for the starting substrate.


b. The substrate binds to the enzyme in the active site to make the enzyme-substrate complex


c. From here, the enzyme has a different effect depending on the reaction, sometimes breaking down the substrate or even forming the desired product, but the enzyme always goes on to be reused.

 

 

Factors for optimal enzyme activity

 

The factors to consider with enzymes include their optimal temperature and pH!

 

Temperature pH

There are 3 key points with TEMPERATURE:

 

- Every enzyme has its favourite temperature, other wise their chemical bonds break and their active sites DENATURE

- Changing the temperature will change the amount of successful molecular collisions

- Too much heat can lead to denaturation

 

Denaturation means the active site starts to breakdown because too high a temperature is breaking the chemical bonds, ruining the active site and slowing the reaction.

 

Regarding molecular collisions, the enzyme and the substrate need kinetic energy to move around so they have a better chance of hitting each other and reacting. But if the temperature dips too low, there is less movement and so less chance of successful collisions being made, slowing down the reaction.

 

However, it’s important to note that not every collision leads to a successful complex as sometimes the substrate goes into the active site but doesn’t react, but optimal conditions mean more collisions and so successful collisions over time are more likely, maintaining a fast rate of reaction.

This can also have a big impact on the active site shape, again because of the sensitivity of the chemical bonds between the amino acids in the folded 3D structure.

 

This leaves the active site vulnerable and if the pH makes a huge change outside the enzyme’s comfort zone, the active site will be denatured, and the substrate won’t be able to fit, which, you guessed it, slows the reaction right down!

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Column A

Column B

Catalyst
A protein that SPEEDS UP the rate of reaction with...
Enzyme-Substrate Complex
A reactant or starting ingredient
Denaturation
When so many chemical bonds are broken between the...
Substrate
When a substance fits exactly into the active site...

Why is it important that an active site is unique?

So the body has a better control over the number of reactions being catalysed

The body doesn't have the ability to make one catalyst that can cover all chemical reactions

So other cells can't steal each other's enzymes and one is left deficent

True or False: 

 

'All molecular collisions between the enzyme and the substrate successfully lead to an enzyme-substrate complex'

So the body has a better control over the number of reactions being catalysed

The body doesn't have the ability to make one catalyst that can cover all chemical reactions

So other cells can't steal each other's enzymes and one is left deficent

An enzyme is made of what subunit?

Fill in the blanks below:

Arrange the example events with the events below that refer to the 'Lock and Key Hypothesis:

Column A

Column B

Enzyme
Glucose
Substrate
Starch
Enzyme- Substrate Complex
Amylase
Product
Amylase binding to Starch

Here is a scenario:

 

'In the stomach, Lipase works best as a catalyst in 37 degrees at pH 2 to break down fats.'

 

Indicate whether the rate of reaction would increase or decrease if the following changes were made:

Kinetic energy is an important point when discussing which concept?

The chemical bonds between the amino acids

Molecular Collisions

The amino acid sequence

Optimal pH

Select all the conditions below that have to be present for an enzyme- substrate complex to successfully occur:

The substrate has to fit into the active site

The enzyme has to be new

The reaction has to take place in the enzyme's optimal temperature

The reaction can only take place once all the product has been cleared away

The reaction has to take place in the enzyme's preferred pH

When an active site has lost its shape so much that it can't do its function, we say it is what?

  • Question 1

khbvk

CORRECT ANSWER

Column A

Column B

Catalyst
A protein that SPEEDS UP the rate...
Enzyme-Substrate Complex
When a substance fits exactly int...
Denaturation
When so many chemical bonds are b...
Substrate
A reactant or starting ingredient
  • Question 2

Why is it important that an active site is unique?

CORRECT ANSWER
So the body has a better control over the number of reactions being catalysed
  • Question 3

True or False: 

 

'All molecular collisions between the enzyme and the substrate successfully lead to an enzyme-substrate complex'

CORRECT ANSWER
  • Question 4

An enzyme is made of what subunit?

CORRECT ANSWER
AMINO ACIDS
AN AMINO ACID
EDDIE SAYS
It's a protein/polypeptide so it's made from an amino acid chain folded on itself with chemical bonds making a 3D shape. This structure allows it to do its job as a catalyst using its specific active site for a specific reaction.
  • Question 5

Fill in the blanks below:

CORRECT ANSWER
  • Question 6

Arrange the example events with the events below that refer to the 'Lock and Key Hypothesis:

CORRECT ANSWER

Column A

Column B

Enzyme
Amylase
Substrate
Starch
Enzyme- Substrate Complex
Amylase binding to Starch
Product
Glucose
  • Question 7

Here is a scenario:

 

'In the stomach, Lipase works best as a catalyst in 37 degrees at pH 2 to break down fats.'

 

Indicate whether the rate of reaction would increase or decrease if the following changes were made:

CORRECT ANSWER
  • Question 8

Kinetic energy is an important point when discussing which concept?

CORRECT ANSWER
Molecular Collisions
  • Question 9

Select all the conditions below that have to be present for an enzyme- substrate complex to successfully occur:

CORRECT ANSWER
The substrate has to fit into the active site
The reaction has to take place in the enzyme's optimal temperature
The reaction has to take place in the enzyme's preferred pH
  • Question 10

When an active site has lost its shape so much that it can't do its function, we say it is what?

CORRECT ANSWER
DENATURED
---- OR ----

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