B2a.2 Food Tests
Q1. An athlete decides to try a new type of protein drink after he exercises.
(a)
The athlete tests the protein drink to check it contains protein.
Which solution is used to test for protein in the drink? Tick one box.
Benedict’s
Biuret
Iodine
Universal indicator
(1)
(b)
What colour will the solution turn to if there is protein in the drink? Tick one box.
Blue-black
Purple
Red
Yellow
(1)
Figure 1 shows the proportion of different nutrients in the protein drink.
(c)
What is the ratio of sugar to protein in the protein drink?
1:1
1:0:6
1:2
1:1:6
(1)
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(d)
Why is a high protein diet useful to an athlete? Tick one box.
Provides amino acids to make new muscle.
Provides fatty acids to produce urea.
Provides glucose for energy.
Provides lactic acid for anaerobic respiration.
(1)
When the athlete drinks the protein drink the substances are digested.
The products of digestion are absorbed into the bloodstream. Absorption
happens in the small intestine.
Figure 2 shows a section of the small intestine.
(e)
How is the small intestine in Figure 2 adapted to absorb the
products of digestion quickly?
Tick two boxes.
It has a large surface area.
It has a long diffusion pathway.
It has a thin surface.
The concentration inside the small
intestine is low.
It has a poor blood supply.
(2)
(f)
Figure 3 shows the proportion of different nutrients in four protein drinks.
Figure 3
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Which protein drink should an athlete with diabetes use?
Give a reason for your answer.
Drink ____________________
Reason ____________________________________________________________
___________________________________________________________________
(2)
Q2. Four foods were tested for starch, sugar and protein. The table shows the results.
Food
(a)
Test for starch:
colour after
iodine test
Test for sugar: Test for protein:
colour after
colour after
Benedict’s test
Biuret test
A
Blue-Black
Brick red
Blue
B
Orange
Blue
Lilac
C
Blue-Black
Yellow
Blue
D
Orange
Orange
Lilac
Give three conclusions about food D.
1 _________________________________________________________________
___________________________________________________________________
2 _________________________________________________________________
___________________________________________________________________
3 _________________________________________________________________
___________________________________________________________________
(3)
(b)
Starch is broken down into glucose. Which type of enzyme breaks down starch?
Tick (✓) one box.
Carbohydrase
Lipase
Protease
(1)
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(c)
Which part of a cell releases energy from glucose? Tick (✓) one box.
(1)
Mitochondria
Nucleus
Ribosomes
Vacuole
(d) Which food in the table above would be the most suitable for a person with Type 2 diabetes to
eat? Give two reasons for your answer.
Food ______________________________________________
Reason 1 ___________________________________________________________
___________________________________________________________________
Reason 2 ___________________________________________________________
___________________________________________________________________
(3)
Q3. Describe how to test a sample of food for protein, starch and sugar.
Give the colours that would be seen if the food sample contained protein, starch and sugar.
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
_____________________________________________________________________________________
___________________________________________________________________________________(6)
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Mark schemes
Q1.
(a)
biuret
1
(b)
purple
1
(c)
1:1.6
1
(d)
provides amino acids to make new muscle
1
(e)
it has a large surface area
1
it has a thin surface
1
(f)
C
1
lowest sugar (content)
1
[8]
Q2.
(a)
it does not contain starch
1
it contains sugar
ignore high / low amount
1
it contains protein
1
(b)
carbohydrase
1
(c)
mitochondria
1
(d)
B
no marks if incorrect or no food given
if no food written on answer line check the table
1
does not contain sugar
1
does not contain starch (that can be converted to sugar)
ignore references to protein
1
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[8]
Q3.
Level 3: The method would lead to the production of a valid outcome. All key steps
are identified and logically sequenced.
5−6
Level 2: The method would not necessarily lead to a valid outcome. Most steps are
identified, but the method is not fully logically sequenced.
3−4
Level 1: The method would not lead to a valid outcome. Some relevant steps are
identified, but links are not made clear.
1−2
No relevant content
0
Indicative content
Protein
•
grind up food
•
add Biuret (reagent / solution)
or
add copper sulfate (solution) and sodium hydroxide (solution)
or
add Biuret 1 and Biuret 2
•
turns purple / lilac
Starch
•
add iodine (solution)
•
turns black / blue-black / dark blue
- ignore blue / purple
Sugar
•
grind up food
•
mix with water
•
add Benedict’s (reagent / solution)
•
heat mixture (≥ 65 °C)
•
in a water bath
•
turns (brick) red / orange / brown / green / yellow
For Level 3 correct references to all three tests are needed.
[6]
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