Enzymes

Question 0

Name two processes that occur in plant or animal cells that require the use of enzymes.

Answer 0

Digestion

DNA Replication

Question 1

Give a detailed account of how enzymes work, referring in your answer to their specificity.

Answer 1

Enzymes are proteins that speed up a reaction without being used up in that reaction.
They are very specific and each one catalyses just one particular reaction. This specificity is related to their 3D- shape and in particular, the shape of the active site, which matches just one substrate. The shape of the active site can be changed in changes in ph or temperature, denaturing the enzyme.

Question 2

Some biological washing powders contain enzymes similar to the ones found in our digestive system. Many of these enzymes are extracted from bacteria.
Suggest why such enzymes are included in washing powder?

Answer 2

Enzymes are included to break down food stains.

Question 3

Why is 40 C the recommended temperature for washing powders?

Answer 3

Because it is the optimum temperature for these enzymes.

Question 4

Suggest what would happen to enzymes in an 80C wash.

Answer 4

Enzymes would be denatured and unable to work so the stains woulod not be removed.

Question 5

Give two advantages of using immobilised yeast cells in the production of alcohol?

Answer 5

1) easy to seperate the yeast cells from alcohol

2) It`s very easy to reuse the immobilised yeast.

Question 6

How did you test the presence of alcohol?

Answer 6

The dichromate test
put potassium dichromate solution in test tube
add 5 drops of the test solution
add 5 drops of concentrated sulphuric acid
warm test tube gently in a beaker of hot water
Potassium dichromate turns from orange to green in presence of alcohol

Question 7

What term is used for the substances that result from action of an enzyme on its substrate?

Answer 7

Product

Question 8

In relation to an enzyme, explain the term optimum activity.

Answer 8

Is the fastest rate for the enzyme.

Question 9

Name the Enzyme you used in your investigations.

Answer 9

Catalase

Question 10

Name the substrate you used in your investigations.

Answer 10

Hydrogen peroxide.

Question 11

Answer the following in relation to enzymes:

What is their chemical nature?

Answer 11

protein

Question 12

Comment on the shape of enzymes.

Answer 12

Folded shape

Question 13

Recording to your investigation, why was it necessary to keep the ph constant ?

Answer 13

Because ph affects the rate of enzyme action by interfering with the shape of the enzyme.

Question 14

How did you keep the ph constant in your investigation?

Answer 14

A buffer solution was added to keep the pH constant.

Question 15

How did you vary the temperature in the course of the investigation?

Answer 15

Temperature was varied by using water baths set at different temperatures.

Question 16

How did you know that the enzyme was working?

Answer 16

Bubbles of oxygen were observed, which produced foam with the washing up liquid.

Question 17

“Enzymes are essential for metabolism”

explain why this statement is true

Answer 17

Enzymes are biological catalysts- they speed up reactions without being used up themselves. Some reactions in the body would not happen quickly enough without enzymes; enzymes are said to control the reactions.

Question 18

State wheter the process is anabolic or catabolic:

PROTEIN SYNTHESIS

Answer 18

anabolic

Question 19

State wheter the process is anabolic or catabolic:

CONVERSION OF ADP TO ATP

Answer 19

anabolic

Question 20

State wheter the process is anabolic or catabolic:

Reactions in which product molecules are larger than substrate molecules.

Answer 20

anabolic

Question 21

State one way by which an enzyme may be denaturated.

Answer 21

An enzyme may be denatured by exposure to high temperatures.

Question 22

Give two features of a denatured enzyme.

Answer 22

They have lost their 3D shape and they are no longer able to catalyse the reaction.

Question 23

Apart from carbon, hydrogen and oxygen, there is one other element always present in the building blocks of enzymes. Name the element.

Answer 23

Nitrogen