Read the information in the passage



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Q1. Read the information in the passage.

 


 

Replacing a damaged heart valve can dramatically improve the blood circulation and the supply of oxygen to the body’s tissues. The operation to replace a heart valve is a long one during which the patient’s blood goes through a bypass machine.
Sometimes the artificial valve can fail to work. If the surface of the valve becomes rough, small blood clots can form on its surface then break away and be carried around the body by the blood.

Evaluate the advantages and disadvantages of artificial heart valves.

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(4)








Q2. Red blood cells have a diameter of about 8 micrometres.

Some capillaries have an internal diameter of about 10 micrometres.

Red blood cells, with antibodies bound to them, stick together.

B antigens are found on the surface of red blood cells in people who have blood group B.

Use this information to explain why transfusion of group B blood into a person of blood group A is unsafe.

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(3)









Q3.          The diagram shows four parts of blood.


          (a)     Complete the table to give the name and function of the parts labelled A, B and C.



Letter

Name

Function

 

A

 

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B

 

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C

 

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(6)




(b)     Red blood cells contain haemoglobin. Explain how this enables red blood cells to pick up oxygen from the alveoli and release it to cells in other parts of the body.

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(4)
(Total 10 marks)

 

Q4.          Oxygen is transported round the body by the blood.

Blood leaving the human lung can carry about 250 milligrams of oxygen per litre.
However, only 7 milligrams of oxygen will dissolve in one litre of water at body temperature.

(a)     Suggest an explanation for the difference.

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(2)




(b)     Blood leaving the skeletal muscles during exercise may contain only 30 milligrams of oxygen per litre.

Explain what causes the difference in oxygen concentration between the blood leaving the lungs and the blood leaving the skeletal muscles.

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(4)
(Total 6 marks)

 

 




Q5. The photographs show the same cells of a common pond plant.

Photograph A shows the cells in a hypotonic solution.

Photograph B shows the same cells in a hypertonic solution.


Photograph A                    Photograph B

 



A & B AELODEA IN HYPOTONIC SOLUTION by fickleandfreckled [CC- BY-2.0], via Flickr.

(a)     What is a hypertonic solution?

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(2)




(b)     What word is used to describe plant cells placed in:

(i)      a hypotonic solution

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(1)
(ii)     a hypertonic solution?

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(1)
(c)     Explain what has happened to the plant cells in Photograph B.

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(4)




(d)     Animal cells will also change when placed in different solutions.

Some red blood cells are put in a hypotonic solution.

Describe what would happen to these red blood cells and explain why this is different from what happened to the plant cells in Photograph A.

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(4)
(Total 12 marks)










Q6. Plants exchange substances with the environment.

(a)     Plant roots absorb water mainly by osmosis.


Plant roots absorb ions mainly by active transport.

Explain why roots need to use the two different methods to absorb water and ions.

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(4)




(b)     What is meant by the transpiration stream?

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(3)














Q7.          A woman suffers a severe infection that affects her kidneys. She is sent to hospital for treatment with a dialysis machine.

A simplified diagram of a dialysis machine is shown below.



 

     Some of the components of the woman’s blood and of the dialysis fluid entering the machine are shown in the table.

 

 

Component

Woman’s blood
entering machine


Dialysis fluid
entering machine


 

Blood cells







 

Glucose







 

Urea






      Key: = present        = absent


Use the information in the table to explain the composition of the dialysis fluid entering the machine.

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(4)
Q8.          (a)     Explain, as fully as you can, why respiration has to take place more rapidly during exercise.

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(2)




(b)     During exercise the process of respiration produces excess heat. Explain how the body prevents this heat from causing a rise in the core (deep) body temperature.

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(4)

(Total 6 marks)

 

 



Q9. In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Homeostasis keeps conditions in the body relatively constant.

The amount of water in the body is controlled by homeostasis.

Kidney function is controlled by a gland in the brain.


Describe how the water content of the blood is controlled.

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(Total 6 marks)



Q10.          In South Asia, forests are being cleared to grow palm oil trees. The palm oil is mainly used to produce fuel for motor vehicles.

The graph shows the production of palm oil in one South Asian country.



Clearing forests and replacing the forests with palm oil trees to produce fuel for motor vehicles will affect the composition of the atmosphere.

Explain how.

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(5)


Q11. Burning some fossil fuels produces acid rain. Explain how acid rain is formed and state one of its effects.

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(4)

 

 


 

M1.     any four from:



to gain 4 marks candidates should include at least:

one advantage and one disadvantage

Advantages

(improved circulation / O2 supply) provides:

•        more cell respiration

•        more energy released

•        (more) active life / not so tired / more physical activity

Disadvantages

•        danger of surgery / operation

•        infection from surgery / operation

•        valve may need replacing

•        clots may form and block blood vessels

may need to take anti-coagulants – eg warfarin

•        clots may cause heart attacks / strokes



4









M2. Group A has anti-B antibodies which bind to B-antigens

1

join / clump RBCs together so too big to pass through capillary / block capillary



1

any one consequence: lack of O2 / food / blood supply to body cells or cells can’t respire



ignore ‘cells die’ / ‘person dies’ - look for cause

1

[3]








M3.          (a)     A white blood cell/leucocytes / phagocytes / lymphocytes

SEPARATE MARKING POINTS

1

          make/contain antibodies/antitoxins


or
destroy/engulf/kill bacteria

do not accept fight infection
do
not accept fight disease

1






B platelets

1

help clot the blood



do not accept stick together
do
not accept from scabs

1






C plasma

1

          carries/transports all the cells/digested food/waste products/hormones/carbon


dioxide/platelets/dissolved minerals/antibodies/antitoxins/water

allows blood to flow



1




(b)     any four from:

(oxygen) diffuses

1

          has affinity for/combines with oxygen / forms oxy-haemoglobin



do not accept absorbed

1




in areas of high oxygen concentration



n.b. ‘pick up oxygen’ is stem of question

1

          in conditions of low oxygen concentration it breaks down and releases the oxygen



low oxygen concentration can be implied e.g. active muscles

1

[10]
M4.          (a)     blood has red (blood) cells / haemoglobin

1






haemoglobin combines with / carries oxygen

ignore ‘mix’

NB Blood can form oxyhaemoglobin = 2 marks

1




(b)     blood gains oxygen / becomes oxygenated (in the lungs)



idea of acquiring oxygen must be unambiguous

1




blood loses oxygen to the muscles / cells



1




because muscles are respiring (aerobically)



1




to provide energy (for exercise)



1

[6]

 

M5. (a)     more concentrated



must be a comparison

1

than the cell / cytoplasm



accept more salty / solutes / ions

accept cell is less concentrated than solution for 2 marks

1




(b)     (i)      turgid



1




(ii)     plasmolysed



accept flaccid

1




(c)     any four from:

•        water left the cells (in A)

•        by osmosis

•        from dilute to more concentrated solution

accept high to low water potential or from high to low water concentration

•        via partially permeable membrane

•        so cell membrane shrank away from cell wall

4




(d)     water enters the cells (by osmosis)



allow 1 mark for:

1

they burst / lyse / lysis occurs



water leaves and cell shrinks (if they think it is hypertonic solution)

1

animal cells have no cell wall or plant cells have a cell wall



1

cell wall prevents lysis / bursting / allows turgidity



allow correct description

1

[12]










M6. (a)    solution in soil is more dilute (than in root cells)

concentration of water higher in the soil (than in root cells)

1




so water moves from the dilute to the more concentrated region



so water moves down (its) concentration gradient or water moves from a high concentration of water to a lower concentration

1




concentration of ions in soil less (than that in root cells)



1




so energy needed to move ions



or

ions are moved against concentration gradient



the direction of the concentration gradient must be expressed clearly

accept correct reference to water potential or to concentrations of water

1




(b)     any three from:

•        movement of water from roots / root hairs (up stem)

•        via xylem

•        to the leaves

•        (water) evaporates

•        via stomata

3















M7.              there is glucose in the dialysis fluid

1

so that glucose does not go out of the blood


or
so that blood glucose concentration unaffected / stays constant

1

there is no urea in the dialysis fluid



1




so that urea diffuses out of the blood into the dialysis fluid and is removed from the body



1







M8.          (a)     more energy needed,
for increased muscular activity

for 1 mark each

2




(b)     increased sweat production,


evaporation of sweat cools body,
vasodilation OWTTE,
more heat loss (by radiation)

for 1 mark each

4

[6]

 


 


M9. Marks awarded for this answer will be determined by the Quality of Communication (QC) as well as the standard of the scientific response. Examiners should also refer to the information on page 5, and apply a ‘best-fit’ approach to the marking.

0 marks
No relevant content.

Level 1 (1 – 2 marks)
There is a brief description of kidney function including a mention of pituitary gland or hormones but roles may be confused.

Level 2 (3 – 4 marks)
There is a clear description of kidney function in relation to fluctuations in blood water levels and the roles of the pituitary gland or hormone is mentioned with correct role.

Level 3 (5 – 6 marks)
There is a clear and detailed scientific description of kidney function in relation to fluctuations in blood water levels and of the roles of the pituitary gland and ADH.

examples of biology points made in the response:

•        if water content too low, ADH released

•        from pituitary gland

•        into the blood

•        (causing) kidney reabsorbs more water

•        more concentrated / small volume urine produced

•        if water content too high, ADH lowered / not produced

•        less water reabsorbed by kidney

•        more dilute / larger volume urine produced

full marks may be awarded for detailed description of either water loss or gain

[6]









M10.

                      ignore references to oxygen / sulfur dioxide / nitrogen oxides / acid rain                  ignore global warming



Effects of deforestation

deforestation increases the amount of carbon dioxide in the atmosphere



award this point only if linked to deforestation

1




any two from:

•        due to less photosynthesis or less carbon dioxide taken in
or carbon dioxide not locked up in (forest) trees

•        due to burning of forest / from machinery

•        due to activity of microorganisms / decay

2






Effects of growing palm for fuel

carbon dioxide released when palm oil used as fuel



1




(eventually) CO2 intake and output might balance out or burning palm


oil carbon neutral

accept less carbon dioxide than from burning fossil fuels

1

[5]

 

M11.          SO2/NO2/CO2 (or words)


or
oxides of nitrogen dissolves/combines/reacts (in water)

do not accept mixes

1

makes an (weak) acid



n.b. acid as an adjective not a noun

1




any one from:

acidification of water/soil

damage to trees/plants



1

          damage/dissolve/erosion of cement or


marble/limestone or metals or
buildings or statues

accept corrodes

kills fish

loss of leaves

1

[4]

 

 





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