(a)
(i)
Cell structure Y in Fig. 1.1 contains a large starch granule (grain).
Name the chemical reagent used to test for starch and state the colour change that will be seen if starch is present.
reagent
colour change
[ 2 ]
[Maximum number: 1]
Fig. 1.1 shows the structures of four biological molecules A, B, C and D.
Fig. 1.1
(a)
Give the letter, A to D, of the molecule in Fig. 1.1 which:
[ 3 ]
(i)
is a nucleotide
(b)
Some of the molecules in Fig. 1.1 can form polymers.
[ 1 ]
(i)
State one way, visible in Fig. 1.1, in which the part labelled 1 of molecule A differs from the part labelled 2.
[ 1 ]
(a)
A person who has type 1 diabetes mellitus cannot produce enough insulin. This results in some glucose being excreted in the urine.
The urine can be tested for glucose using a dip stick.
Name the two enzymes present on the dip stick and outline the reaction catalysed by each enzyme.
enzyme
reaction
enzyme
reaction
[ 2 ]
[Maximum number: 3]
Lipase is an enzyme with many commercial uses. Some species of bacteria are of great interest as they produce large quantities of lipase.
(a)
To measure the activity of the bacterial lipase during their investigations, the researchers used a method based on the biological test for triglycerides.
Outline a biological test that could be carried out to show the presence of triglyceride in a liquid mixture and describe the positive result for this test.
[ 3 ]
[Maximum number: 1]
The diagram shows some similarities between chloroplasts, mitochondria and typical prokaryotes.
Which row is correct?
1
2
3
4
5
chloroplasts
circular DNA
mitochondria
linear DNA
prokaryotes
mitochondria
linear DNA
chloroplasts
70S ribosomes
prokaryotes
mitochondria
70S ribosomes
chloroplasts
linear DNA
prokaryotes
prokaryotes
70S ribosomes
mitochondria
70S ribosomes
chloroplasts
[Maximum number: 1]
The size of the measles virus is approximately 150 nm .
The Mimivirus is approximately 4.5 times larger than the measles virus, whilst the Pandoravirus is approximately 1.5 times larger than the Mimivirus.
Which viruses can be seen using both a light microscope with a maximum resolution of and an electron microscope?
measles virus
Mimivirus
Pandoravirus
key
✓ = can be seen
cannot be seen
✓
✓
✓
x
✓
✓
x
✓
x
×
[Maximum number: 1]
Tests on four samples from a mixture of biological molecules gave the results shown in the table.
Which biological molecules were in the mixture?
A
reducing sugar and protein
B
reducing sugar, non-reducing sugar and starch
C
non-reducing sugar and protein
D
non-reducing sugar and starch only
[Maximum number: 1]
After boiling a sample of milk with Benedict's solution, a yellow colour is observed.
Which conclusion about the sample of milk is correct?
A
Reducing sugars are not present.
B
Reducing sugars are present.
C
There is a high concentration of fructose.
D
There is a low concentration of sucrose.
[Maximum number: 1]
Steps 1-4 are used to test for a non-reducing sugar.
1 Put of solution into a test-tube.
2 Add a few drops of acid.
3 Neutralise with alkali.
4 Add Benedict's solution.
When is the solution boiled?
A
between steps 1 and 2
B
between steps 2 and 3 and after step 4
C
between steps 2 and 3 only
D
after step 4 only
[Maximum number: 1]
Samples of a mixture of biological molecules were tested using Benedict's reagent, biuret solution and ethanol. After testing, the solutions were blue with Benedict's reagent, purple with biuret and cloudy with ethanol.
Which molecules could the mixture contain?
Z
A
W, X and Y
B
W, X and Z
C
W, Y and Z
D
X, Y and Z