Enzymes revision questions
Q1. (a)
This student is examining plant cells.
This shows the student’s labelled diagram of one of the plant cells.
Vacuole
Cytoplasm
Nucleus
Chloroplasts
Cell membrane
Cell wall
Complete each, of the following sentences.
(i)
The cell wall is made of ..................................................................... .
(ii)
The function of the cell wall is to ........................................... the cell.
(iii)
Chloroplasts contain ........................................... which is needed for
...................................... .
(iv)
The vacuole contains ....................................... which is mostly water.
(5)
(b)
This student is investigating enzymes.
(i)
What is the temperature of the water in the beaker?
................................... °C
(1)
(ii)
What does an enzyme do?
...........................................................................................................................
...........................................................................................................................
...........................................................................................................................
(2)
(iii)
Enzymes have many uses. For example they are used in some washing powders.
Give two examples of other uses for which enzymes, or products containing
enzymes, are sold.
1. .....................................................................................................................
2. ....................................................................................................................
(2)
(c)
An enzyme is used in a chemical reaction. The graph shows the speed of the reaction
at different temperatures.
Fast
Speed
of
reaction
Slow
37 °C
Temperature
(i)
Complete the following sentence in your own words.
At 37 °C the reaction ........................................................................................
...........................................................................................................................
(1)
(ii)
What makes you think that this enzyme could work well in the human body?
...........................................................................................................................
...........................................................................................................................
(1)
(Total 12 marks)
Q2. (i)
What is the name of the process which takes place in living cells in your body and
which releases energy from oxygen and glucose?
.....................................................................................................................................
(1)
(ii)
Name the two products of the process in part (i).
............................................................... and ..............................................................
(1)
(Total 2 marks)
Q3. (a)
Starch and protein are foods which have to be digested before they can be absorbed.
For each, state the enzyme involved in the digestion process, where it occurs in the
digestive system and what is formed and absorbed.
Food
Enzyme
Where digestion occurs
What is formed and absorbed
Starch
...............
......................................
..................................................
Protein ...............
......................................
..................................................
(4)
The diagram shows part of the lining of the small intestine. Digestion involves the
breakdown of large molecules to smaller ones which are absorbed into the blood
stream through the microvilli of the epithelial cells.
Microvilli
Epithelial cell
Part of a
villus
lining the
small
intestine
Capillary
(b)
Why are epithelial cells, which form the lining of the small intestine, adapted to be the
shape shown?
....................................................................................................................................
....................................................................................................................................
(1)
(Total 5 marks)
Q4. We use enzymes in industry. These are some of the properties of enzymes:
 they work at low temperatures and this can save energy
 they work at atmospheric pressures and therefore use less expensive equipment
 they are easily broken down by high temperature or the wrong pH
 they are soluble in water, so it is difficult to separate them from water-soluble products
 they are very expensive to buy.
(a)
Use the information above to answer this question.
(i)
Give two advantages of using enzymes in industry.
1 ...........................................................................................................................
................................................................................................................................
2 ............................................................................................................................
................................................................................................................................
(ii)
Give two disadvantages of using enzymes in industry.
1 ...........................................................................................................................
................................................................................................................................
2 ..........................................................................................................................
...............................................................................................................................
(4)
(b)
Different enzymes have different jobs:
 protease enzymes break down proteins so that they are easier to digest
 lipase enzymes break down fats
 carbohydrase enzymes break down starch into sugar for energy drinks
 isomerase enzymes break down glucose into fructose which is much sweeter.
Which enzyme is used:
(i)
to help to get greasy stains out of clothes?
................................................................
(ii)
in making slimming foods?
........................................................................................
(iii)
in making baby foods?
...............................................................................................
(3)
(Total 7 marks)
Q5. Bread contains starch, protein and fat.
(a)
Complete each sentence by choosing the correct words from the box.
amino acids
fat
fatty acids
protein
starch
sugar
Amylase speeds up the digestion of .................................... . The product of this digestion
is ............................. . Protease speeds up the digestion of ............................. .
The product of this digestion is .............................................. .
(4)
(b)
Why do molecules of starch, protein and fat need to be digested?
...............................................................................................................................
................................................................................................................................
(2)
(c)
In which part of the digestive system does the digestion of starch begin?
Draw a ring around your answer.
large intestine
mouth
small intestine
stomach
(1)
(d)
What do we call substances like amylase and protease which speed up chemical
reactions?
...........................................................................................................................(1)
(Total 8 marks)