Unit 1: Protein Booklet LOs

Question 1

1

Answer 1

Proteins are made of a chain of amino acids

Question 2

2.

Answer 2

The order of amino acids determines the function of a protein

Question 3

3. What can proteins function as?

Answer 3

Structural, enzymes, hormones, antibodies and receptor proteins.

Question 4

4. Describe the properties of an enzyme

Answer 4

Made of proteins- Proteins have many functions which include enzymes. Enzymes are therefore made of protein and protein is made from a chain of amino acids.
Biological catalysts- Enzymes speed up cellular reactions and are unchanged in the process. They speed up all biochemical reactions that take place in all living things.
Specific- The part of the enzyme which binds to a substrate is called the active site. The active site of each type of enzyme has a different shape from any other type of enzyme so that it will only bind to one type of substrate. This makes enzymes specific to one type of substrate.
Most active at optimum conditions- Each enzyme is most active in it’s optimum conditions. Enzymes and other proteins can be affected by temperature and PH.
Denatured at high temperature- In certain conditions, an enzyme will become denatured. This is where the active site changes and will no longer allow the substrate to bind to it. This lowers the rate of reaction.

Question 5

5. Explain the importance of enzymes.

Answer 5

Enzymes are biological catalysts. This means that they speed up all biochemical reactions and remain unchanged by the reaction. Enzymes can be involved in degradation and synthesis reactions. A degradation reaction is where a large substance is broken down into smaller products. A synthesis reaction is where smaller substrate molecules are built into larger products.

Question 6

6. Describe an enzyme reaction.

Answer 6

Enzymes can be involved in degradation and synthesis reactions. During an enzyme reaction, the enzyme and it’s substrate fit together to form a complex in the same way as a key fits a lock. In a degradation reaction, the larger substrate binds to the enzyme’s active site and the substrate is broken down into smaller products. In a synthesis reaction, smaller substrate molecules bind the enzyme’s active site and these molecules are built up into larger products

Question 7

7. Explain the specificity of enzymes for their substrate.

Answer 7

The part of the enzyme which binds to the substrate is called the active site. The active site of each enzyme has a different shape from any other type of enzyme so that it will only bind to one type of substrate. This makes enzymes specific to one type of substrate.

Question 8

8. Give examples of degradation reactions.

Answer 8

Amylase
Starch——————->Maltose
Phosphorylase
Hydrogen peroxide————————>starch

Question 9

9. Give an example of a synthesis reaction

Answer 9

Phosphorylase
Glucose-6-phosphate————————>starch

Question 10

10. Name the factors which affect enzyme activity

Answer 10

Temperature and PH

Question 11

11. Explain what is meant by the phrase ‘optimum conditions’

Answer 11

At low temperatures, the molecules move slowly so the reaction is slow. At high temperatures, the shape of the active site changes and will no longer allow the substrate to bind to it. This lowers the rate of reaction. The conditions when the enzyme is most active is it’s optimum conditions.

Question 12

12. Describe and explain an enzyme activity graph

Question 13

13. Explain what happens when an enzyme is denatured.

Answer 13

In certain conditions, the shape of the active site changes and will no longer allow the substrate to bind to it. This lowers the rate of reaction.