1.
Test for Protein
a. Positive result shown by tube number?
b. Name of reagent or indicator to test protein is…..
c. This food test needs to be heated or no?
2.
Test for Starch
a. Positive result shown by spot number?
b. Name of reagent or indicator to test starch is…..
c. This food test needs to be heated or no?
3.
Test for Reducing Sugar
a. Positive result shown by tube number?
b. Name of reagent or indicator to test sugar is…..
c. This food test needs to be heated or no?
4.
Test for Lipid/Fat
a. Positive result shown by tube number?
b. Name of reagent or indicator to test sugar is…..
c. This food test needs to be heated or no?
5.
Indicators: Iodine solution
a. The reagent was used to test food that contain …
b. Mention 3 sample foods that contain nutrient (a)!
c. Positive result shown by spot number?
6.
Indicators: Biuret solution
a. The reagent was used to test food that contain …
b. Mention 5 sample foods that contain nutrient (a)!
c. Positive result shown by tube number?
7.
Indicators: Benedict’s Solution
a. The reagent was used to test food that contain …
b. Mention 5 sample foods that contain nutrient (a)!
c. Positive result shown by tube number?
8.
Indicators: Alcohol
a. The reagent was used to test food that contain …
b. Mention 5 sample foods that contain nutrient (a)!
c. Positive result shown by tube number?
9.
Enzymes
An analyst does following experiment!
Tube Solution added
Indicator
A
Albumin + Water
Biuret
B
Albumin + Protease
Biuret
If the tubes keep about 30’, what will happen to each tube and explain it!
10.
Enzymes
An analyst does following experiment!
Tube Solution added
Indicator
A
Starch + Water
Iodine
B
Starch + Amylase Iodine
If the tubes keep about 30’, what will happen to each tube and explain it!
11.
Enzymes
An analyst does following experiment!
Tube Solution added
Indicator
A
Starch + Water
Benedict’s
B
Starch + Amylase Benedict’s
If the tubes keep about 30’ then heated, what will happen to each tube and explain
it!
12.
Enzymes
An analyst does following experiment!
Tube Solution added
Indicator
A
Albumin + Water
Biuret
B
Albumin + HCl
Biuret
C
Albumin + Protease
Biuret
D
Albumin + HCl + Pepsin
Biuret
If the tubes keep about 30’, what will happen to each tube and explain it!
13.
Enzymes
An analyst does following experiment!
Tube Solution added
Indicator
A
Starch + Water
Iodine
B
Starch + Heated
Iodine
C
Starch + Amylase
Iodine
D
Starch + Amylase + Heated
Iodine
If the tubes keep about 30’, what will happen to each tube and explain it!
14.
Test for Protein
a. State the positive result of this food test!
b. Mention 3 apparatus that needed for this experiment!
c. Protein made from?
15.
Test for Lipid/Fat
a. State the positive result of this food test!
b. Mention 3 apparatus that needed for this experiment!
c. Lipid made from?
16.
Test for Starch
a. State the positive result of this food test!
b. Mention 3 apparatus that needed for this experiment!
c. Carbohydrate made from?
17.
Test for Protein
a. Positive result shown by tube number?
b. Describe 4 steps to test foods that contain Protein!
18.
Test for Reducing Sugar
a. Positive result shown by tube number?
b. Describe 4 steps to test foods that contain Reducing Sugar!
19.
Test for Lipid/Fats
a. Positive result shown by tube number?
b. Describe 4 steps to test foods that contain Lipids!
20.
Test for Starch
a. Positive result shown by spot number?
b. Describe 4 steps to test foods that contain Starch!
Name:
Answer Sheet
1
a.
Class:
No:
c.
6
a.
b.
b.
c.
c.
2
a.
7
a.
b.
b.
c.
c.
3
a.
8
a.
b.
b.
c.
c.
4
a.
9
Tube A:
b.
Tube B:
c.
10
5
Tube A:
a.
Tube B:
b.
11
Tube A:
c.
Tube B:
16
12
a.
Tube A:
b.
Tube B:
c.
Tube C:
17
a.
Tube D:
13
Tube A:
b.
Tube B:
18
a.
Tube C:
b.
Tube D:
19
14
a.
b.
b.
c.
15
a.
20
a.
a.
b.
b.
Practical Test Grade 7th Chapter 4 and 5
1. A student investigated the time taken for amylase to
breakdown a 10% starch solution into glucose at 37oC. The
student repeated the investigation five times with result as
below table!
Time taken for amylase to produce glucose (s)
Test 1
Test 2
Test 3
Test 4
Test 4
120
125
110
115
118
(i) Calculate the rate of amylase enzyme activity for the 10%
starch solution.
The tubes keep about 30’, the change/s that will occur on
each tube is/are
A
B
C
D
4. Below are some experiments.
(i) The diagram shows two foods carried out on solution X.
Rate =………………..
(ii) The investigation was done at 37oC, state one other
variable that the student should have controlled during this
investigation.
(iii) Explain why enzymes can only catalyse specific reaction.
What nutrients are present in solution X?
(iv) What happens to an enzyme when its active site
changes shape irreversibly?
2. Carbohydrates, fats and proteins are food groups found in
a balanced diet.
(i) Name one element contained in all these food groups
………………………………………………………………………
……………………………………………………………
(ii) The data show the concentrations of sugar and starch in
an onion.
Total sugar / g per 100g
Starch /g per 100g
3.7
0
The onion is tested with Benedict’s solution an iodine
solution. Predict the results in colour change and explain
briefly the reason of the results.
Test
Results
Reason
Benedict’s
(ii) The lists give three foods and five food groups
Each food is made up of main food group
Draw the lines to link each food to its main food group.
Type of food
Food Group
Fat
Potato
Protein
Butter
Mineral
Carbohydrate
Iodine
5. Tina investigates the enzyme amylase. She already
knows these facts.
The enzyme amylase breaks down starch in the mouth.
The pH in the mouth is 7.
Iodine solution is very dark blue when there is starch.
Iodine solution is yellow when there is no starch.
She uses this apparatus.
Chicken
Vitamin
3. An analyst does following experiment!
(i) Tina wants to check her prediction by doing an
investigation. Some variables need to be kept the same and
some need to be changed. Tick () the variables she needs
to keep the same.
7. Three test tubes were set up as follows. The test tubes
were kept at 37 oC.
- Test tube A contained 2 cm 3 of starch suspension and 2
cm3 of salivary amylase.
- Test tube B contained 2 cm 3 of starch suspension and 2
cm3 of pancreatic lipase.
- Test tube C contained 2 cm 3 of starch suspension and 2
cm3 of distilled water.
(ii) Tina wants to control risks when carrying out this
investigation. Suggest one way she could make sure she is
safe.
Tina writes her results in a table.
pH
Result
3
Stay dark blue
5
Changes from dark blue to yellow very slowly
7
Changes from dark blue to yellow very slowly
9
Changes from dark blue to yellow very slowly
11
Stay dark blue
(iii) What conclusion can you draw from Amrit’s results?
(iv) Suggest one way to improve Amrit’s investigation.
6. A student did an experiment with the enzyme pepsin. He
used six text tubes labelled A-F.
 Pepsin solution of the same volume was placed in each
test tubes.
 The pepsin solution in tubes D, E and F was boiled for
two minutes.
 Three drops of hydrochloric acid were added to tubes B
and D.
 Three drops of sodium hydroxide were added to tubes
C and E.
 Solid egg white was added to each of the six test tubes.
 The test tubes were then placed in a water bath at 36
oC.
a. What is the nutrient tested in the experiment?
b. Complete the result of the experiment in the table below.
A
B
C
D
E
F
Before
White
White White White White White
heating
After
Slightly
Clear
heating
clear
c. If he wanted to make sure the nutrient has been digested
completely, suggest the most suitable reagent.
d. Compare A and B after heating, suggest a reason for the
difference in the result.
(i) Complete the following table to show what would happen
if iodine solution was added to each of the test tubes after 24
hours. Explain the result obtained for each test tube.
Test
tube
A
Colour
Explanation
B
C
(ii) What would have been the effect of increasing the
temperature to 45oC?