Jan 2013 Unit 1

Question 1

Formula for Pulmonary ventilation

Answer 1

Tidal volume x ventilation rate

Question 2

This photograph was taken using a transmission electron microscope. The structure of
the organelles visible in the photograph could not have been seen using an optical
(light) microscope. Explain why

Answer 2

1. Has low resolution/not high
   enough resolution;
2. (Because) wavelength of light
   not short enough/too long

Question 3

The water potential of solution B was higher (less negative) than the water potential of
solution A.
Explain why

Answer 3

Starch is not (very) soluble/does not

dissolve well

Question 4

Addition of a phosphate group to the non-functional form of TK leads to production of the functional form of TK.
Explain how.

Answer 4

1. (Phosphate) changes shape of
TK/changes shape of
enzyme/changes the active site;
2. Active site forms/becomes the
right shape

Question 5

Suggest how faulty TK leads to chronic myeloid leukaemia.

Answer 5

1. Faulty TK has functional active
site without phosphate;
2. (So, faulty) TK functional all the
time/TK not controlled (by
phosphate)

Question 6

Using all of the information, describe how imatinib stops the development of chronic
myeloid leukaemia.

Answer 6

1. Non-competitive inhibitor/binds
to site other than active site;
2. Causes TK to be in nonfunctional
form/active site not
formed/wrong shape/E-S
complex not formed;
3. So, (uncontrolled) cell division
stopped/slowed/controlled;

Question 7

In these patients, the right ventricle still produces sufficient blood flow to keep the
patient alive.
Suggest why the left ventricle requires the help of the artificial heart but the right
ventricle does not.

Answer 7

1. Left ventricle pumps to whole
body (except lungs)/pumps
blood further;
2. Left ventricle does most
work/produces a greater
pressure/produces a greater
force;

Question 8

Valves A and B have the same functions as heart valves involved in the cardiac cycle.
Name the heart valve that has the same function as:

Answer 8

1. (Valve A) atrioventricular valve;

2. Semi-lunar valve;

Question 9

Which type of artificial heart was the more successful? Use calculations to support
your answer.

Answer 9

X because (no mark)
1. 52.1% survived without
replacement compared to
12.1% / difference of 40%;
2. 10.9% required repair or
replacement of artificial heart
compared to 41.4% / difference
of 30.5%;
3. 37% died compared to 46.6% /
difference of 9.6%;

Question 10

The groups of men selected for this investigation were matched.
Other than being men, suggest one factor for which they should have been matched

Answer 10

age

Question 11

Explain why the pulse recordings in the doctor’s surgery were taken when the men
were lying down.

Answer 11

Patients were at rest

Question 12

The pulse felt in the artery in the wrist can be recorded and used to measure heart
rate.
Suggest why the pulse felt can be used to measure heart rate

Answer 12

1. Caused by pressure/surge of
   blood;
2. From (one) contraction/beat of
   (left) ventricle/heart;

Question 13

The portable heart rate monitor recorded the men’s heart rates continuously.
This gave more reliable mean heart rates than those obtained by recording the pulse in
the wrist for 1 minute.
Suggest why it is more reliable

Answer 13

1. Monitor records heart rate over
long period of time/all the
time/more data collected;
2. Anomalies in recording have
less effect

Question 14

A journalist, who saw these results, stated that they showed there is no such thing as
white-coat hypertension.
Do these data support this statement? Give reasons for your answer

Answer 14

1. Men with condition always have
   higher heart rates;
2. But no direct measurements of
   blood pressure

Question 15

People with AIDS die because they are unable to produce an immune response to
pathogens (lines 2– 4).
Explain why this leads to death.

Answer 15

1. Infected by/susceptible to
   (other) pathogen(s)/named
   disease caused by a pathogen
   (from environment);
2. Pathogen(s) reproduce/cause
   diease (in host);
3. Damage cells

Question 16

Explain why each of the following means that a vaccine might not be effective against
HIV.
HIV rapidly enters host cells (lines 6 –7)

Answer 16

1. (HIV enters cells) before
   antibodies can bind to/destroy it;
2. Antibodies cannot enter cells

Question 17

HIV shows a lot of antigenic variability (lines 7– 8).

Answer 17

1. Antigen (on HIV) changes;
2. (Specific) antibody/receptor no
   longer binds to (new) antigen;

Question 18

So far, these types of vaccine have not been considered safe to use in a mass
vaccination programme (lines 14 – 15).
 Suggest why they have not been considered safe

Answer 18

1. Inactive virus may become
active/viral transformation;
2. Attenuated virus might become
harmful;
3. Non-pathogenic virus may

Question 19

Some substances can cross the cell-surface membrane of a cell by simple diffusion
through the phospholipid bilayer.
Describe other ways by which substances cross this membrane.

Answer 19

By osmosis (no mark)
1. From a high water potential to a
low water potential/down a
water potential gradient;
2. Through aquaporins/water
channels;
By facilitated diffusion (no mark)
3. Channel/carrier protein;
4. Down concentration gradient;
By active transport (no mark)
5. Carrier protein/protein pumps;
6. Against concentration gradient;
7. Using ATP/energy (from
respiration);

Question 20

Atheroma formation increases a person’s risk of dying.

Explain how.

Answer 20

1. Atheroma is fatty
material/cholesterol/foam
cells/plaque/calcium
deposits/LDL;
2. In wall of artery;
3. (Higher risk of)
aneurysm/described;
4. (Higher risk of) thrombus
formation/blood clot;
5. Blocks coronary artery;
6. Less oxygen/glucose to heart
muscle/cells/tissue;
7. Reduces/prevents respiration;
8. Causing myocardial
infarction/heart attack