Jun 203 Unit 1

Question 1

Name the type of reaction that joins monosaccharides together.

Answer 1

condensation

Question 2

Name one organelle that you would expect to find in large numbers in a
mucus-secreting cell and describe its role in the production of mucus.

Answer 2

3. Rough endoplasmic
   reticulum/ribosomes;
4. Make polypeptide/protein/forming
   peptide bonds

Question 3

Name the process by which oxygen passes from an alveolus in the lungs into the blood.

Answer 3

diffusion

Question 4

Describe two adaptations of the structure of alveoli for efficient gas exchange

Answer 4

1. Thin walls/cells;

2. (Total) surface area is large

Question 5

People who have been fire-breathers for many years often find they cannot breathe out properly. Explain why

Answer 5

1. Loss of elasticity/elastic tissue;
2. Scar tissue;
3. Less recoil;

Question 6

Describe the relationship between sea temperature and the number of people admitted
to hospital with cholera between January and June.

Answer 6

1. Both show little/no increase/remain
constant in January/February;
2. (Up to May) sea temperature rises
more quickly/before increase in
cholera;

Question 7

Some scientists have suggested that a rise in sea temperatures could lead to an
increase in outbreaks of cholera. Do these data support this suggestion? Give
reasons for your answer.

Answer 7

1. Positive correlation from January to
September/October (between sea
temperature and cholera cases);
2. Only records people in hospital with
cholera / may be people with
cholera not in hospital;

Question 8

In areas where there are repeated outbreaks of cholera, most people who become
infected by cholera bacteria do not become ill. Suggest and explain one reason why

Answer 8

1. Have produced memory cells;

2. After previous infection/vaccination

Question 9

The scientists measured the rate of uptake of imatinib in µg per million cells per hour.
Explain the advantage of using this unit of rate in this investigation.

Answer 9

1. To allow comparison;
2. Because different number of cells in
   samples

Question 10

Imatinib is taken up by blood cells by active transport.

Explain how the data for the two different temperatures support this statement

Answer 10

1. (At every concentration) uptake is
   faster at 37C/at higher temperature;
2. Due to faster respiration/ATP
   production

Question 11

Explain how the data for concentrations of imatinib outside the blood cells at
50 and 100 µmol dm–3 at 37 ºC support the statement that imatinib is taken up by active
transport.

Answer 11

1. Uptake at 37oC only small increase
/levelling off/almost constant;
2. As carrier proteins full;
3. Concentration of imatinib is not the
limiting factor

Question 12

Describe how you would test a sample of food for the presence of starch.

Answer 12

1. Add iodine/potassium iodide solution
   to the food sample;
2. Blue/black/purple indicates starch is
   present

Question 13

The concentration of glucose in the blood rises after eating a meal containing
carbohydrates.
The rise is slower if the carbohydrate is starch rather than sucrose. Explain why

Answer 13

1. Starch digested to maltose/by
amylase;
2. Maltose digested to glucose/by
maltase;
3. Digestion of sucrose is a single
step process whilst the digestion of starch involves two steps.

Question 14

The scientists excluded women who smoked from the study. Explain why.

Answer 14

Introduces another variable

Question 15

What do these data show about the effect that glycaemic load of the diet has on the
risk of developing CHD?

Answer 15

1. No effect on risk with diet group 1
and 2/lowest glycaemic load;
2. Above diet group 2/in higher groups,
risk increases as glycaemic load
increases

Question 16

Use the information provided to explain the effect that glycaemic load of the diet has on the risk of developing CHD

Answer 16

1. For diet group 2 and above,
increase in risk of CHD as GL
increases;
2. (Higher GL diets lead to) more
(harmful) lipids (in blood), so greater
risk of atheroma;
3. Atheroma leads to blockage of
coronary artery / increased risk of
blood clot in coronary artery

Question 17

Microfold cells do not have adaptations for the absorption of food (lines 2 - 3).
Give two adaptations that other epithelial cells have for the absorption of food.

Answer 17

1. Microvilli;
2. Carrier proteins/co-transport
   proteins/membrane-bound
   enzymes;
3. Many mitochondria

Question 18

Microfold cells have receptor proteins on their cell-surface membranes that bind to
antigens (line 5). What is an antigen?

Answer 18

Substance that causes an immune

response/ production of antibodies

Question 19

Microfold cells take up the antigens and transport them to cells of the immune system
(lines 6 - 7). Antigens are not able to pass through the cell-surface membranes of
other epithelial cells. Suggest two reasons why

Answer 19

1. Not lipid soluble;

2. Too large to simply diffuse through bilayer

Question 20

Scientists believe that it may be possible to develop vaccines that make use of
microfold cells (lines 9 -10). Explain how this sort of vaccine would lead to a person
developing immunity to a pathogen.

Answer 20

1. (Vaccine contains)
antigen/attenuated/dead pathogen;
2. Microfold cells take up/bind and
present/transport antigen (to
immune system/lymphocytes/Tcells);
3. T-cells activate B-cells;
4. B-cells divide/form clone/undergo
mitosis;
5. B-cells produce antibodies;
6. Memory cells produced;
7. More antibodies/antibodies
produced faster in secondary
response/on reinfection

Question 21

Explain how the heart muscle and the heart valves maintain a one-way flow of blood from the left atrium to the aorta.

Answer 21

1. Atrium has higher pressure than
ventricle (due to filling/contraction);
2. Atrioventricular valve opens;
3. Ventricle has higher pressure than
atrium (due to filling/contraction);
4. Atrioventricular valve closes;
5. Ventricle has higher pressure than
aorta;
6. Semilunar valve opens;
7. Higher pressure in aorta than
ventricle (as heart relaxes);
8. Semilunar valve closes;
9. (Muscle/atrial/ventricular)
contraction causes increase in
pressure