Download File - Rights4Bacteria

Q1.
In fish and chip shops, potatoes are cut into chips several hours before the chips are
cooked.
The amount of water in the chips must be kept constant during this time.
To keep the water in the chips constant, the chips are kept in salt solution.
A student investigated the effect of different concentrations of salt solution on the mass of five
chips.
•
He weighed each one of the five chips.
•
He placed each chip into a different concentration of salt solution.
•
After one hour he removed the chips from the salt solutions and then reweighed the chips.
Concentration of salt solution
0M
0.5 M
1M
2M
3M
Mass of chip at start, in
grams
2.6
2.8
2.8
2.5
2.6
Mass of chip after one
hour, in grams
2.7
2.8
2.7
2.3
2.1
(a)
(i)
In which concentration of salt solution did the chip gain mass? .................
(1)
(ii)
Explain why the chip gained mass in this solution.
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(2)
Page 1 of 7
(b)
In which concentration of salt solution should the chips be kept in the shop?
Give the reason for your answer.
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(2)
(Total 5 marks)
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The table shows the concentrations of some mineral ions in the cells of a pond plant and in the
surrounding pond water.
Concentration in mmol per dm3
Potassium
(i)
Calcium
Sulphate
Plant cells
49.0
7.0
7.0
Pond water
0.5
0.7
0.4
The plant cells would not have been able to absorb these mineral ions from the pond water
by diffusion. Explain why not.
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(2)
(ii)
Suggest a process which would allow these ions to be absorbed from the pond water by
the plant cells.
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(1)
(Total 3 marks)
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Q3.
The drawing shows part of a root hair cell.
(a)
Use words from the list to label the parts of the root hair cell.
cell membrane
cell wall
cytoplasm
nucleus
vacuole
(4)
(b)
The diagram shows four ways in which molecules may move into and out of a cell. The
dots show the concentration of molecules.
The cell is respiring aerobically.
Which arrow, A, B, C or D represents:
(i)
movement of oxygen molecules;
(ii)
movement of carbon dioxide molecules?
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(2)
(c)
Name the process by which these gases move into and out of the cell.
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(1)
(Total 7 marks)
Q4.
Plants need chemical energy for respiration and for active transport.
(i)
Write a balanced chemical equation which represents the process of respiration in plants.
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(2)
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(ii)
Describe the process of active transport in the root hair cells of plants.
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(3)
(Total 5 marks)
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M1.
(a)
(i)
0M
1
(ii)
water entered cells by osmosis
1
because the concentration of water outside cells was
higher than inside the cells
1
(b)
0.5 M
1
because the chip did not change mass in this solution
1
[5]
M2.
(i)
in diffusion: material moves high to low concentration
1
here: concentration in cells > concentration in water or
uptake is against the concentration gradient or by diffusion ions would move out
1
(ii)
active transport / active uptake
1
[3]
M3.
(a) (cell) wall
(cell) membrane
cytoplasm
vacuole
for 1 mark each
4
(b)
(i)
A
(ii)
B
for 1 mark each
2
(c)
diffusion
(reject osmosis)
for 1 mark
1
[7]
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M4.
(i)
C6H12O6 + 6O2 → 6CO2 + 6H2O
energy is neutral
1
formulae all correct
with no omissions / deletions
correctly balanced
credit 1 mark if the answer is the exact
reverse of an incorrect answer for (a)
1
(ii)
and three from
take up of (soluble) substances / ions against the concentration gradient
or when the concentration (of the
substance / ions) is greater inside the
cell / cytoplasm than outside it
through the (semi-permeable) (cell) membrane energy from mitochondria
or energy from respiration
not just energy
3
[5]
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