-
8/2/2019 2005 Jan Module 4B
1/12
1. The table below refers to some regions of the brain and their
functions. Complete the table by
inserting the correct word or words.
Region of brain One function
Medulla
Learning and memory
Control of balance and fine movement
Hypothalamus
(Total 4 marks)
2. An investigation was carried out into the effect of cyanide
on the respiration of yeast cells.
Cyanide is an electron transport inhibitor. It binds
irreversibly with one of the electron carriers.
The yeast cells were mixed with a buffer solution which had ADP,
phosphate ions and glucose
dissolved in it. This suspension was incubated for 30 minutes
and during this time the oxygen
content of the solution was monitored using an oxygen probe.
The experiment was then repeated but cyanide was added to the
suspension after 5 minutes of
incubation.
The results obtained are shown in the graph below.
1 0
8
6
4
2
00 5 1 0 1 5 2 0 2 5 3 0
T i m e o f i n c u b a t i o n / m
N o c y a n
C y a n i d e
O x y g e n c o n t e n t o f t h e s u s p e n s i o n/ a r b i
t r a r y u n i t s
(a) State precisely where the electron transport chain is
found.
......................................................................................................................................(1)
94855231.doc 1
-
8/2/2019 2005 Jan Module 4B
2/12
(b) Explain why the oxygen content of the suspension did not
change after the cyanide was
added.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(2)
(c) Suggest why the oxygen content of the suspension of cells
without cyanide did not reach
zero.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(2)
(Total 5 marks)
3. Neurones transmit electrical impulses along their cell
surface membranes when stimulated to do
so. These impulses are called action potentials and involve
changes in the electrical potential
across the membranes due to movement of positive ions.
The diagram below shows the distribution of charge inside and
outside an unmyelinated axon as
an impulse passes along.
+ + + + + + + + + + + +
+ + + + + + + + + + + +
D C B A
A x o n
D i r e c t i o n o f i m p
94855231.doc 2
-
8/2/2019 2005 Jan Module 4B
3/12
(a) Use the most suitable term from the list below to describe
the state of the axon in regions
B, C and D. Region A has been done for you.
Depolarising Resting Repolarising
A Resting
B
......................................................................
C
......................................................................
D
......................................................................(2)
(b) The diagram below shows two action potentials recorded using
an oscilloscope.
+ 6 0
+ 4 0
+ 2 0
0
2 0
4 0
6 0
8 0
1 0 0
M e m b r a n ep o t e n t i a l/ m V
0 1 2 3 4 5 6 7 8 9
T i m e / m s
X
(i) Explain how the change in membrane potential between 0.5 and
2.0 milliseconds is
brought about.
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................(4)
94855231.doc 3
-
8/2/2019 2005 Jan Module 4B
4/12
(ii) Calculate the number of action potentials occurring per
second. Show your
working.
Answer .................................. per second(2)
(c) Explain what is taking place during the period marked X on
the diagram in part (b).
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(3)
(Total 11 marks)
4. The graph below shows how the rates of filtration and
reabsorption of glucose in human
nephrons vary with the concentration of glucose in the blood
plasma.
R a t e o f f i l t r a t i o no r r e a b s o r p t i o no f g
l u c o s e/ m m o l m i n
4
3
2
1
0
1
3
0 1 0 2 0 3 0 4 0
C o n c e n t r a t i o n o f g l u c oi n b l o o d p l a s m a
/ m m o l
F i l t r a t i o
R e a b s o
94855231.doc 4
-
8/2/2019 2005 Jan Module 4B
5/12
(a) Name the region of the nephron where glucose is filtered and
the region where it is
reabsorbed.
Region of glucose filtration
..........................................................................................
Region of glucose reabsorption
....................................................................................
(2)
(b) Name one other substance which is reabsorbed in the same
part of the nephron as glucose.
......................................................................................................................................(1)
(c) With reference to the graph, describe the relationship
between filtration rate and
reabsorption rate as the concentration of glucose in the blood
plasma increases.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(3)
(d) Using the information in the graph, explain why glucose
appears in the urine when the
plasma glucose concentration exceeds 10 mmol per dm3
.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(2)
94855231.doc 5
-
8/2/2019 2005 Jan Module 4B
6/12
(e) Suggest why the presence of glucose in the urine results in
the production of a larger
volume of urine than when glucose is not present.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(3)
(Total 11 marks)
5. Give an account of the detection of light by pigments in the
mammalian eye.
(Allow two lined pages)(Total 9 marks)
6. The discovery of the hormone leptin has caused much interest
to nutritionists since it influences
body mass index and obesity.
(a) Explain what is meant by the following terms.
(i) Body mass index
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................(2)
(ii) Obesity
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................(2)
94855231.doc 6
-
8/2/2019 2005 Jan Module 4B
7/12
(b) Explain why obese people are at a significantly greater risk
of developing coronary heart
disease than non-obese people.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(3)
(Total 7 marks)
7. Sterilisation of milk involves the following stages.
P r e h e a t i n g t
F i l t e r i n g
H o m o g e n i s i n
A u t o c l a v i n g ( ha t 1 1 5 C f o r
(a) State two effects of this sterilisation process on the
milk.
1
...................................................................................................................................
......................................................................................................................................
2
...................................................................................................................................
......................................................................................................................................
(2)
94855231.doc 7
-
8/2/2019 2005 Jan Module 4B
8/12
(b) (i) Describe how the turbidity test can be carried out on a
sample of milk.
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................(3)
(ii) Explain how the results of this test can be used to
determine whether the
sterilisation process has been effective.
...............................................................................................................................
...............................................................................................................................(1)
(Total 6 marks)
8. An investigation was carried out into the effect of packaging
on the loss of mass in tomatoes.
Freshly picked tomatoes were divided into two groups, each
containing ten tomatoes. One group
was left unwrapped, while the other was placed in a
polythene-wrapped pack.
The initial mass of both groups of tomatoes was recorded, with
an allowance made for the massof the packaging. Both groups were
kept in the same conditions of humidity and temperature and
their mass was recorded every two days for a period of six
days.
The results are shown in the table below.
Mass of tomatoes / g
Time / days Unwrapped In polythene-wrapped pack
0 730 735
2 712 729
4 694 722
6 664 714
94855231.doc 8
-
8/2/2019 2005 Jan Module 4B
9/12
(a) Explain why the unwrapped tomatoes lost mass during the
six-day period.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(3)
(b) Plastic films, such as polythene, can be used to create a
modified atmosphere inside a
package.
Explain why a modified atmosphere with increased carbon dioxide
and lowered oxygenconcentration can help extend the shelf life of
fresh fruit.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(2)
(c) Give one advantage, other than reducing loss in mass, of
using polythene-wrapped packsfor selling fruit in shops.
......................................................................................................................................
......................................................................................................................................(1)
(Total 6 marks)
94855231.doc 9
-
8/2/2019 2005 Jan Module 4B
10/12
9. The calorific (energy) value of raw and cooked potatoes is
shown in the chart below. In each
case, the sample was dried in an oven before the calorific value
of 1 gram was determined. The
results are shown in the graph below.
1 0 0 0 0
9 0 0 0
1 5 0 0
1 0 0 0
5 0 0
0
C a l o r i f i c v a l u e/ J g 1
R a wp o t a t o
B o i l e dp o t a t o
F r i e dp o t a t o
(a) How many times greater is the calorific value of fried
potato than the calorific value of
boiled potato? Show your working.
Answer .......................................(2)
(b) Suggest why there is a difference between the calorific
value of boiled and fried potato.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(3)
94855231.doc 10
-
8/2/2019 2005 Jan Module 4B
11/12
(c) Suggest why the potato samples were dried in an oven before
their calorific values were
determined.
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................
......................................................................................................................................(2)
(d) One of the factors influencing the amount of energy needed
in the diet of a person is their
basal metabolic rate (BMR).
The graph below shows how the BMR of men and women varies with
their age.
B M R / a r b i t r a r y u n i t s
7 0
6 5
6 0
5 5
5 0
4 5
4 0
3 5
0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8
A g e / y e a r s
M a l e s
F e m a l e s
(i) Explain what is meant by BMR.
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................(2)
94855231.doc 11
-
8/2/2019 2005 Jan Module 4B
12/12
(ii) Suggest why the BMR of males is higher than that of
females.
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................
...............................................................................................................................(2)
(Total 11 marks)
94855231.doc 12
