MAY 2010
BIOLOGY
PAPER I
MARKING SCHEME
1.
a. Beneficial effect: can help land reclamation/ filling old quarry/ land not
abandoned/safe space instead of putting refuse in other open spaces/avoids burning of
wastes/ land can be reused
1 mark
Do not accept cleaner environment/ more green land/recycling/less toxic
wastes/disposed waste cannot reach river/introduce nutrients/remove eyesore/develop
new habitats/quarry used for good environmental use
Problem: site can attract pests (such as rats)/increased traffic/pungent
smells/leaching/river can be contaminated
1 mark
Do not accept eyesore/visual/light pollution/toxins leach to water table
b. Reduces access to pests/allows bacteria and fungi to decompose organic
compounds/generates biogas that can be used to fuel machinery
1 mark
Do not accept less smell/good for soil/not a eyesore/can be later planted with trees
c. Reduction in the greenhouse gas (carbon dioxide); less soil erosion; provides
valuable wildlife habitats for local fauna
(1 mark each)
3 marks
If students mention reduce global warming award half a mark/if students mention
homes or spaces i/o habitats award half a mark
Accept: increases awareness/aesthetic /recreational value/encourages afforestation/
Do not accept maintain levels of oxygen/tourist attraction/mention of transpiration
d. Increases air content in soil
1 mark
Prevents waterlogged soils
1 mark
Accept mixing of nutrients/removal of weeds/soften soil/soil is not hard/easier to sow
seeds
Do not accept keeps soil fertile/prevent erosion
e. Apply small quantities of fertiliser; do not apply fertiliser if rain is forecast; apply
fertiliser only when crops are growing; never apply fertiliser to bare fields; do not
dispose of waste fertiliser into rivers or ponds. Any TWO
2 marks
Accept use natural/organic fertilisers/green manure/do not over-water
f. Reduction in greenhouse emissions; less combustion of fossil fuels
1 mark
If students mention less pollution/no gases released/it is renewable/less damage to
environment give half a mark
Total: 11 marks
2.
a.
A: Diabetes/diabetic
1 mark
B: Anaemia
1 mark
Award half a mark if spelling is incorrect (correct phonetics)
b. Malfunctioning pancreas
1 mark
c.
i Scurvy
ii Rickets
Award half a mark if spelling is incorrect (correct phonetics)
1
1 mark
1 mark
Do not accept oesteoporosis
Due to lack of calcium and
Vitamin D in the diet thus causing bending of bones
1 mark
1 mark
2 marks
e. Night blindness is caused by a lack of Vitamin A in the diet.
1 mark
Carrots are a good source of Vitamin A that can help to prevent night blindness.
1 mark
Total: 9 marks
3a. Osmosis is the diffusion of water molecules down a water potential gradient.
2 marks
If students mention water movement from a high concentration of water to a low
concentration of water award 2 marks
Award 2 marks if semi permeable membrane is mentioned along with water
concentration
b.
i Arrow entering the cell - X
1 mark
Arrow leaving the cell - Y
1 mark
ii Cell X becomes turgid.
Cell Y becomes flaccid/plasmolysed
Do not accept swelling up/shrinks/soft/rigid
Do not penalise students for wrong spelling of terms.
c. Plant cells have a thick cell wall
that withstands the pressure made by water entering cell.
1 mark
1 mark
1 mark
1 mark
d. Water moves out of the cherries as the solute concentration of the sugar solution is
very high.
1 mark
Cells become plasmolysed.
1 mark
Total: 10 marks
4a.
Structure
Group of organisms
Cone
Gymnosperms
flower (multiple of 3)
Monocot
Jointed appendage
Arthropod
Fin
Fish
Tentacles
Coelenterate
Flower (multiple of 5)
Dicot
(1 mark each) 6 marks
Do not accept wrong spelling – do not award any mark
b. Bryophytes do not have vascular tissue while ferns do.
2 marks
(Accept Bryophyes lack lignified cells while ferns have lignified walls./
Do not award marks if students mention true roots, stems, leaves )
c. Ferns have a waxy cuticle covering their leaves therefore they reduce water loss.
2 marks
Total: 10 marks
2
5a.
Box 3 (Lag phase)
Box 4(log phase)
Little or no growth
Period of constant growth/rapid growth
rate/maximum growth rate Do not accept
accelerating growth rate
Box 1 (Stationary phase)
Growth rate becomes limited /population
is maintained but no new growth
Box 2 (Death phase)
Decelerating/decreasing growth rate
(1 mark each) 4 marks
Award 0.5 mark if students refer to cell number.
b.
i Redworm and water louse
2marks
ii Tolerant to low oxygen levels
1 mark
Lack of competition in oxygen – deficient water.
1 mark
(Accept an increase in nutrients; predation; award 0.5 marks for tolerant to
pollution/sewage)
iii The increase in mayfly population increases rapidly
1 mark
resulting in interspecific competition between the two species/mayfly preys on water
lice.
1 mark
Accept: water louse is intolerant to sewage award 1 mark
Total: 10 marks
6a. Leaf 1
1 mark
All stomata are exposed/none of the stomata pores are clogged/blocked with vaseline.
1 mark
b. Leaf 3 has a higher transpiration rate than leaf 4 because leaf 3 has fewer blocked
stomata than leaf 4 thus showing that most stomata are found on the underside of
these leaves/more stomata present on the underside of leaf.
2 marks
c. The surface area determines the number of stomata on the leaf surface. The same
surface area guarantees that all four leaves have an approximately same number of
stomata. (Accept only one factor should be varied at a time)
2 marks
If students mention for accuracy/fairness of experiment award 1 mark
d. Temperature, air humidity and air currents.
Any TWO
2 marks
Accept same surface area of leaf
Do not accept light/sunlight accept light intensity
e. Transpiration is useful to cool the plant. (Accept to have the necessary water for
photosynthesis/ uptake of water & minerals.)
1 mark
Total: 9 marks
3
7 a. Lime water B turns milky
1 mark
this is because carbon dioxide is produced by green plant during respiration. 1 mark
Lime water A remains clear
1 mark
This is because sodium hydroxide solution removes all carbon dioxide from incoming
air.
1 mark
b.
Test tube
A
B
C
Change predicted
No colour change expected/remains
the same/remains yellow
Do not accept it is yellow/turns
brown
Orange precipitate/brick red/brown
Blue black colour/deep
purple/purple black
Simple reducing sugar present
Accept glucose/maltose is present
Starch present
Simple reducing sugar
absent/accept no sugar present
Do not accept starch is present
(0.5 mark each) 4 marks
Total: 8 marks
8a. Bird ringing provides a record of migration patterns or routes/aspects of bird
ecology including survival rates/breeding rates/helps research bird population
dynamics eg. to find how long they live and learn about aspects of their behaviour.
2 marks
b. The reed beds provide a habitat to several fauna including reptiles and small
mammals. OR They also provide safety to several species of birds
2 marks
Any ONE or equivalent
Do not accept to provide oxygen/prevent flooding/to prevent erosion
Give 1 mark for source of food/start off a food chain
c. Narrow leaves with parallel veins.
1 mark
Award 0.5 mark for long leaves
d. i Fleshy leaves to store water /prevents leaves from drying up
1 mark
ii Xylem
1 mark
Total: 8 marks
9a.
D
No colour change present
Remains blue (do not accept lilac)
Reason
No starch present/starch digested
to maltose
4
(1 mark for each correct label award the mark ONLY if spelling is correct)
(Accept sap instead of vacuole )4 marks
b. The cell membrane is a thin skin that surrounds the cell while the cell wall is a
rigid/firm coat round the outside of the cell.
2 marks
The cell membrane holds the cell together and controls what goes in and out of the
cell. While the cell wall is made of cellulose and helps the cell keep its shape.2 marks
c.
Description
Tissue used in the translocation of organic
solutes
Tissue conducts nerve impulses
Contracts to support and move the body
Tissue found in leaf containing numerous
chloroplasts
Tissue acts as the living protective layer in leaf
Tissue carries substances round the body
Name of tissue
Phloem
Nervous tissue
Award 0.5 mark if nerve
tissue/brain tissue is mentioned
Do not accept nerve
cell/neurone
Muscle tissue/muscoloskeletal
tissue
Mesophyll
Award 0.5 marks for palisade
layer
Do not accept photosynthetic
tissue
Epidermis
Do not accept dermis
Blood
Accept ONLY blood
(1, 1, 1, 1, 1 mark)
Total: 14 marks
10a
i Sweat is produced to decrease body temperature/to cool body
Award 0.5 mark to keep constant body temperature.
ii Alveolar surface is moist/lungs are humid
Do not accept produced during respiration.
iii Most of the water is reabsorbed in the large intestine.
Do not accept to decrease constipation/faeces are solid/easier egestion/to
dehydration
b.
i Adrenal glands
ii Renal artery
iii Nephron /kidney tubule
1 mark
1 mark
1 mark
prevent
1 mark
1 mark
1 mark
5
c.
i Ultrafiltration occurs – this separates substances from rest of blood.
(if filtration only is mentioned award 0.5 mark)
ii Selective reabsorption of glucose and minerals ( and some water).
(if reabsorption only is mentioned award 1 mark
If absorption only is mentioned award 0.5 mark)
iii Selective reabsorption of water.
(Accept mention of longer nephron )
2 marks
2 marks
2 marks
Total: 12 marks
6