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Year 8 Revision of Written test
Homeroom:
Date:
1. The graph shows the time taken for 1 gram of starch to be digested at different temperatures.
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10
9
8
7
Time for starch digestion
(minutes)
6
5
4
3
2
1
0
0
10
20
30
40
50
60
70
Temperature (oC)
(a)
(i)
At which temperature was the starch digested
most quickly?
40oC
(ii)
most slowly?
60oC
(b)
At which two temperatures did it take 4 minutes for the starch to be digested?
(i) 23oC
(ii) 50oC
(c)
Which of these types of enzymes digests starch?
proteases
carbohydrases
lipases
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carbohydrases
(d)
What is starch digested into?
sugar/maltose/glucose
(e)
How to test for starch?
Starch turns iodine solution from brown to
dark blue
(f)
Describe how you would carry out a starch test. What would show a positive result?
 add iodine solution to sample,
dark blue colour indicates starch is present
(g)
Describe how you would carry out a test for glucose.
What would show a positive result?
 add Benedict's reagent to sample;
 heat in water bath;
 orange colour indicates glucose is present;
2. Complete the following table by choosing the correct function from the table. Write the number of the
function in the box. The first one has been completed as an example.
FUNCTION
1. Chews and grinds food.
4. Stores bile.
2. Absorbs water from food.
5. Produces acid and a protein-digesting enzyme.
3. Produces bile.
6. Absorbs digested food into the blood.
Part of digestive
system
Teeth
Gall bladder
Stomach
Liver
Small intestine
Large intestine
Function
1
4;
5;
3;
6;
2;
3. The diagram shows the main parts of the digestive system
2
Mouth
A
P
Stomach
Q
Small
intestine
R
Large
intestine
S
(a)
Name structure A. Choose from this list below.
duodenum
rectum trachea
oesophagus
oesophagus
(b)
How is food moved along structure A?
peristalsis
(c)
As food passes along the digestive system enzymes are added to it. There are three types of digestive enzyme lipases, carbohydrases and proteases. Which of these types of enzyme is produced in:
(i) the mouth?
carbohydrases
(ii) the stomach?
proteases
(d)
The pancreas also produces digestive enzymes. Which of the positions, P, Q, R or S shows the position of the
pancreas?
Q
(e)(i)
In which part of the digestive system are villi found?
small intestine
(iii) What is the function of villi?
Absorption
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4. The diagram below shows part of the human digestive system.
B
A = stomach;
B = liver;
C = duodenum/small intestine;
D = colon/large intestine;
(a)
On the diagram, name the parts A, B, C and D.
(b)
Name one part of the digestive system where:
(i)
A
C
D
bile is produced.
liver/B
(ii) faeces are stored.
rectum
(iii) the digestion of protein begins.
stomach/A
(iv) carbohydrase, protease and lipase enzymes are produced.
small intestine/ileum/C/pancreas
5. The table below lists some features of 3 digestive juices. If a feature is correct place a tick () in the
appropriate box and if it is incorrect place a cross in the appropriate box. The first feature has been answered
for you.
Feature
is slightly alkaline
(pH above 7).
contains a proteindigesting enzyme.
Saliva
Gastric juice
Pancreatic juice

X

X


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contains lipase.
helps to kill bacteria
taken in with food
contains amylase
passes down the
oesophagus
is produced by the
stomach
6. (a)
(i)
X
X

X

X

X


X
X
X

X
Name the part of the digestive system where:
most absorption of digested food takes place.
small intestine/ileum
(ii) most absorption of water takes place.
large intestine/colon
(b)
The diagram shows a villus used to absorb food from the digestive system. During absorption
food passes from the intestine into the blood.
epithelium of villus
blood vessels
(i)
State two ways in which a villus is adapted to speed up absorption.
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Any two of:
 large surface area/
 thin surface/thin
epithelium/epithelium one cell
thick;
 good blood supply
(ii) Name one process by which digested foods may be absorbed.
diffusion/active transport
(c)
Describe what happens to food which is not digested and absorbed.
water absorbed;
forms faeces;
passed out of anus;
7. The table shows the nutritional requirements of a 16 year old male.
Mass
Energy requirement per day
Energy required from carbohydrates
Energy required from fat
Mass of protein required per day
74 kg
9,180 kJ
2/3 of daily requirement
1/3 of daily requirement
1.2 g per kg of body mass
Carbohydrate has an energy value of 17 kJ per gram and fat has an energy value of 35 kJ per gram
(a)
Calculate the mass of protein needed per day by the 16 year old male. Show your working.
74 x 1.2g =88.8 grams;
(correct answer scores 2. Allow 1 mark
for correct working but incorrect answer)
(b) (i) Calculate how much energy the 16 year old should obtain from carbohydrate. Show your working.
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2/3 of 9180 =6120 kJ;
(correct answer scores 2. Allow 1 mark
for correct working but incorrect answer)
(ii) Calculate the mass of carbohydrate the 16 year old would need to eat to supply the energy needed from
carbohydrate. Show your working.
1 gram of carbohydrate =
17 kJ.
6120/17=360grams
of carbohydrate
(correct answer scores 2. Allow 1 mark for correct working but incorrect answer)
(c)
Eskimos of the same age have a daily energy requirement which is 40% higher. Suggest a reason for this.
extra energy needed to
maintain body temperature
in cold conditions
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