(4) (1)ii)€€€€ Explain, as fully as you can, why water was lost most rapidly under these...

Q1. The diagram shows part of the breathing system in a human.

(a) Use words from the list to label the parts on the drawing.

alveoli bronchiole bronchus diaphragm trachea (windpipe)

(4)

(b) Where in the lungs does oxygen enter the blood?

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(c) Which process in cells produces carbon dioxide?

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(Total 6 marks)

Q2. Blood contains red blood cells, white blood cells and platelets.

(a) Give the function of platelets.

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The photograph shows a red blood cell.

(b) The average diameter of a real red blood cell is 0.008 millimetres. On the photograph, the diameter of the red blood cell is 100 millimetres.

Use the formula to calculate the magnification of the photograph.

diameter on photograph = real diameter × magnification

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Magnification = .................................... (2)

(c) Some blood capillaries have an internal diameter of approximately 0.01 millimetres.

Use information given in part (b) to explain why only one red blood cell at a time can pass through a capillary.

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(d) (i) Red blood cells transport oxygen.

Explain how oxygen is moved from the lungs to the tissues.

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(ii) Red blood cells have no nucleus.

Explain how this feature is an adaptation to the function of red blood cells.

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(e) Oxygen is exchanged between the blood capillaries and the tissue.

Give two ways in which capillaries are adapted for exchanging oxygen with the tissues.

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(Total 10 marks)

Q3. (a) Name the process by which water is lost from plant leaves.

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(b) Some students set up the apparatus shown in the diagram to measure the water loss from a potted plant.

The apparatus was placed in different environmental conditions:

A in still air at 20 °C.

B in still air at 25 °C.

C in a wind at 20 °C.

D in a wind at 25 °C.

Readings from the balance were recorded by a datalogger at 10-minute intervals.

The results are given in the table.

(i) Under which conditions, A, B, C or D, was water lost most rapidly? (1)

Time in minutes

Balance reading in grams

A B C D

0 285.6 284.6 282.9 280.9

10 285.3 284.2 282.4 280.2

20 284.9 283.8 281.9 279.4

30 284.7 283.4 281.4 278.8

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(ii) Explain, as fully as you can, why water was lost most rapidly under these conditions.

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(Total 4 marks)

Q4. Four leaves were removed from the same plant. Petroleum jelly (a waterproofing agent) was spread onto some of the leaves, as follows:

Leaf A: on both surfaces Leaf B: on the lower surface only Leaf C: on the upper surface only Leaf D: none applied

Each leaf was then placed in a separate beaker, as shown in diagram 1.

Diagram 1

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Each beaker was weighed at intervals. The results are shown in the graph.

(a) Give evidence from the graph in answering the following questions.

(i) Which surface (upper or lower) loses water most rapidly? .............................

Evidence ...........................................................................................................

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(ii) Is water lost from both surfaces of the leaf? ....................................................

Evidence ...........................................................................................................

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(b) Diagram 2 shows the appearance of each surface of the leaf as seen through a microscope.

Upper Surface of Leaf Lower Surface of Leaf

Diagram 2

(i) Name space X and cell Y.

X ...................................................................

Y ................................................................... (2)

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(ii) Use information in diagram 2 to explain why the results are different for leaves B and C.

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(Total 6 marks)

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As they go higher up a mountain, mountaineers take less oxygen into their bodies with each breath, as shown in the table below.

MILLIGRAMS OF OXYGEN INTO BLOOD WITH EACH NORMAL BREATH

HEIGHT

MILLIGRAMS OF OXYGEN TAKEN INTO LUNGS WITH EACH NORMAL BREATH

AT FIRST

AFTER STAYING AT 4500 METRES FOR

TWO WEEKS

sea-level 300 60 90

1500 metres 250 50

3000 metres 200 40

4500 metres 150 30 45

(a) (i) How does the amount of oxygen taken into the blood with each breath vary with the amount of oxygen breathed into the lungs with each breath?

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(ii) Use the idea of diffusion to explain why the amount of oxygen taken into the blood varies in this way.

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(b) (i) How does staying at an altitude of 4500 metres for two weeks affect the mountaineers?

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(ii) Suggest an explanation for this.

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(iii) Add the two missing figures to the right-hand column of the table. (2)

(Total 8 marks)

Q6. Two balloonists decide to go up to 5000 metres. At this level the air is less dense, so the mass of oxygen in each lungful of air they breathe is less than at sea-level.

Describe, in as much detail as you can, how the mass of oxygen in the balloonists’ blood changes as they go up from sea-level to 5000 metres.

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Q7. (a) Some scientists investigated the rates of absorption of different sugars by the small intestine.

In one experiment they used a piece of normal intestine. In a second experiment they used a piece of intestine poisoned by cyanide. Cyanide is poisonous because it prevents respiration.

The results are shown in the table.

(i) Name two sugars from the table which can be absorbed by active transport.

1 ........................................................................................................................

2 ........................................................................................................................ (1)

Relative rates of absorption

Sugar Normal intestine Intestine poisoned

by cyanide

Glucose 1.00 0.33

Galactose 1.10 0.53

Xylose 0.30 0.31

Arabinose 0.29 0.29

(ii) Use evidence from the table to explain why you chose these sugars.

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(b) All of the sugars named in the table can be absorbed by diffusion.

Explain how information from the table provides evidence for this.

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(Total 6 marks)

Q8. (a) The concentration of sulfate ions was measured in the roots of barley plants and in the water in the surrounding soil.

The table shows the results.

Is it possible for the barley roots to take up sulfate ions from the soil by diffusion?

Draw a ring around your answer. Yes / No

Explain your answer.

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Concentration of sulfate ions in mmol per dm3

Roots of barley plants 1.4

Soil 0.15

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(b) Some scientists investigated the amounts of sulfate ions taken up by barley roots in the presence of oxygen and when no oxygen was present.

The graph below shows the results.

(i) The graph shows that the rate of sulfate ion uptake between 100 and 200 minutes, without oxygen, was 0.4 arbitrary units per minute.

The rate of sulfate ion uptake between 100 and 200 minutes, with oxygen, was greater.

How much greater was it? Show clearly how you work out your answer.

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Answer ..................... arbitrary units (2)

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(ii) The barley roots were able to take up more sulfate ions with oxygen than without oxygen.

Explain how.

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(Total 7 marks)

Q9. The small intestine is lined with millions of villi. The diagram shows the structure of a villus.

In the small intestine, some of the products of digestion are absorbed into the blood by active transport.

(a) Explain what is meant by active transport.

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(b) How do microvilli and mitochondria help in the active transport of the products of digestion from the small intestine into the blood?

Microvilli ....................................................................................................................

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Mitochondria ..............................................................................................................

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(Total 4 marks)

Q10. A potted plant was left in a hot, brightly lit room for ten hours. The plant was not watered during this period. The drawings show how the mean width of stomata changed over the ten hour period.

(a) Why do plants need stomata?

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(b) Name the cells labelled X on the drawing.

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(c) The width of the stomata changed over the ten hour period. Explain the advantage to the plant of this change.

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(Total 4 marks)

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Q11. The photograph shows a red blood cell in part of a blood clot. The fibres labelled X are produced in the early stages of the clotting process.

(a) Suggest how the fibres labelled X help in blood clot formation.

..................................................................................................................................... (1)

(b) The average diameter of a real red blood cell is 0.008 millimetres. On the photograph, the diameter of the red blood cell is 100 millimetres.

Use the formula to calculate the magnification of the photograph.

Diameter on photograph = Real diameter × Magnification

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Magnification = .............................................................. (2)

(c) Some blood capillaries have an internal diameter of approximately 0.01 millimetres.

(i) Use information given in part (b) to explain why only one red blood cell at a time can pass through a capillary.

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(ii) Explain the advantages of red blood cells passing through a capillary one at a time.

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(Total 7 marks)

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M1. (a) trachea / windpipe bronchus alveoli diaphragm

for 1 mark each 4

(b) alveoli / air sacs (reject capillaries) for one mark

1

(c) respiration for one mark

1 [6]

M2. (a) forming clot at site of wound 1

(b) 12 500 correct answer gains 2 marks

ignore any units 2

(c) size of RBC approximately same size as capillary

or

no room for more than one cell

or

only one can fit

or

RBC is too big allow use of numbers do not accept capillaries are narrow

1

(d) (i) in lungs oxygen diffuses (from the alveoli) into the blood 1

in the red blood cell, oxygen combines with haemoglobin, forming oxyhaemoglobin

1

in tissues oxyhaemoglobin splits up, releasing oxygen, which diffuses into the cells

1

if answer incorrect, gains 1 mark

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(ii) allows cell to have more haemoglobin for oxygen transport 1

(e) thin walls for short diffusion path 1

narrow, so have a large surface area to volume ratio 1

[10]

M3. (a) transpiration / evaporation / diffusion

ignore osmosis 1

(b) (i) D 1

(ii) any two from:

• more / faster diffusion or evaporation or transpiration

• molecules move faster

• maintains concentration gradient or keeps water concentration low in the air or brings in more dry air or removes damp air / water

2 [4]

M4. (a) (i) lower – B loses less (water / mass) than C or described in terms of petroleum jelly

accept converse re Leaf C 1

(ii) yes - B and C lose less than D or B and C lose more than A or D loses the most or A loses the least

do not accept just ‘all leaves lose some weight’ 1

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(b) (i) X = stoma

accept stomata / stomatal pore do not accept air space

1

Y = guard cell 1

(ii) petroleum jelly blocks stomata / pores or petroleum jelly prevents water loss or petroleum jelly waterproofs

allow pores are blocked in B 1

water (mainly) lost via stomata / pores / X or stomata on lower surface only

1 [6]

M5. (a) (i) increasing one increases the other

gains 1 mark

but they increase in proportion/ 1/5 taken in at first / 3/10 taken in after 2 weeks

gains 2 marks 2

(ii) idea that more/faster diffusion with higher concentration for 1 mark

or with more oxygen particles/molecules (in same space)

1

(b) (i) can take more oxygen from (the same) air/changes from 30 to 45/increases by 15

gains 1 mark

but takes 50% more or 1.5 times as much

gains 2 marks

or increases by 15 mg breath

2

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(ii) more red blood cells develop or more haemoglobin in the blood (not just ‘acclimatises’)

for 1 mark 1

(iii) 75 60

each for 1 mark 2

[8]

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ideas that

• mass of oxygen in blood unaffected/stays at 2.0g per litre at low altitudes

• mass of oxygen in blood falls at higher altitudes

• starts to fall above 2500 metres

• 75 g per litre (at 5000 metres) Don’t credit simply “gets lower as you get high”, but don’t penalise for 1 mark each

[4]

M7. (a) (i) glucose and galactose 1

(ii) any three from:

Evidence:

• absorption reduced by cyanide allow converse

• absorb faster (than other sugars)

Explanation:

• active transport needs energy

• less / no energy available / released if cyanide is there or less / no energy if no / less respiration

allow energy produced ignore cyanide prevents respiration

3

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(b) all / the sugars / they can be absorbed when gut poisoned / with cyanide or when no respiration

1

(diffusion) does not need an energy supply 1

[6]

M8. (a) No

no mark if yes max 1 for correct statement

diffusion is down the concentration gradient accept by diffusion ions would leave the root

1

to enter must go up / against the concentration gradient or concentration higher in the root or concentration lower in the soil

1

(b) (i) 0.9 or 3.25

for correct answer with or without working if answer incorrect 1.3 or their rate – 0.4 gains 1 mark or 130 – 40 or 90 gains 1 mark

2

(ii) (uptake) by active transport 1

requires energy

more energy from aerobic respiration 1

or

more energy when oxygen is present 1

[7]

M9. (a) any two from:

• transport up / against concentration gradient / low to high concentration

• uses energy

• use of protein / carrier 2

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(b) microvilli – large(r) surface area accept have carriers

1

mitochondria – release energy or make ATP

do not accept ‘makes energy’ 1

[4]

M10. (a) allow carbon dioxide to enter / gaseous exchange (oxygen neutral) (transpiration neutral)

for one mark 1

(b) guard (cells) for one mark

1

(c) stops / reduces the rate of water loss / transpiration (reject if dark initiated) stops / reduces wilting / description e.g. drooping / maintains turgor

for 1 mark each 2

[4]

M11. (a) hold cells together or prevent flow of cells or trap cells 1

(b) 12500 if correct answer, ignore working / lack of working

for 1 mark

ignore any units

2

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(c) (i) size RBC approximately same size capillary or no room for more than one cell or only one can fit or RBC is too big

allow use of numbers do not accept capillaries are narrow

1

(ii) more oxygen released (to tissues) or more oxygen taken up (from lungs)

1

and any two from:

• slows flow or more time available

• shorter distance (for exchange) or close to cells / capillary wall

• more surface area exposed 2

[7]

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(4) (1)ii)€€€€ Explain, as fully as you can, why water was lost most rapidly under these...

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Transcript of (4) (1)ii)€€€€ Explain, as fully as you can, why water was lost most rapidly under these...