Download Biology paper 1 ms MBOONI WEST SUB – COUNTY JOINT

Biology paper 1 ms
MBOONI WEST SUB – COUNTY JOINT EXAMINATION 2013
BIOLOGY
PAPER 1
MARKING SCHEME
1. (a) Mitochondrion; (Reject mitochondria)
(1mk)
(b) Golgi bodies/Golgi apparatus;
(1mk)
2 (a) Habitat –A specific locality/place (with a particular set of conditions) where organisms live;
Ecological niche- Is a position that an organism occupies in a habitat/food chain /feeding relationship;
3. Maintains salt- water balance/osmotic pressure to optimum levels; in the body tissues /fluids; that is favourable to
normal functioning of cells;
4. It has a large surface area exposed to its aquatic environment; gaseous exchange is therefore by (simple) diffusion
across its membrane;
(2mks)
5. (a) Dicotyledonae;
(1mk)
(b) Centrally placed star shaped Xylem with phloem (alternatively) between the arms of the Xylem;
(b) is tired to (a)
(1mk)
(c)
6. (a)
Numerous/Elongated to increase surface area for absorption of water/minerals/both;
Thin walled for faster absorption of water/mineral salts/or both;
Numerous mitochondria to provide energy for absorption of mineral salts;
Large sap vacuole to create high osmotic pressure;
Any one correct 1x1 =1mk
Semi- circular canalsMaintenance of body balance and posture;
(1mk)
(b) Eustachain
It equalizes air pressure in the outer and middle ear to prevent distortion of the ear drum/tympanic membrane;
(1mk)
7. (a) Epicotyl;
(1mk)
(b) - It enables the seedling to be firmly anchored in the ground;
- It enables the seedling to obtain water and mineral salts;
(2mks)
8. Due to increased carbon (IV) oxide/green house gases;
The atmosphere forms a layer which prevents escape of terrestrial/ground radiation into the outer atmosphere; heat
is therefore retained in the lower atmosphere; This results in increased atmospheric temperatures hence global
warming;
(3mks)
9. (a) Femur
(1mk)
(b) (i)
K – Pelvic girdle/ innominated born;
(1mk)
(Reject the fused bones);
(ii)
L – Tibia;
Accept Tibia and fibula.
Reject Fibula and tibia.
10. (a) Deamination;
(1mk)
(b) Removal of excess amino acids;
- Availing energy in the body;
- Formation of glycogen/fat for storage;
(any 2 correct 1x2 =2mks)
(b) is tired to (a)
11. (a) Photosynthesis;
(b) Carbon (IV) oxide concentration; (the valency power correctly)
Temperature;
Amount of chlorophyll;
(b) is tired to (a)
(Any two correct 1x2 =2mks)
12. Y - Chromosome – Tuft of hair from the pinna/ premature baldness; (1mk)
X – Chromosome – Colour blindness/Haemophilia;
Duchenne muscular dystrophy; (1mk)
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Biology paper 1 ms
13. (a) A rat is endothermic/homoithermic;
It requires more energy to maintain;
Its body temperature constant ;unlike a lizard which is exothermic/poikilothermic; hence uses environmental
heat to generate body temperature;
14. (a) Magnification = Eye piece lens maginification X objective lens magnification;
X 450 = X45;
X 10
(Reject if 45X is absent missing)
The working should be seen for the answer to score
(b) Use to bring an image (of a specimen) into sharp focus;
1mk
15
Skeletal muscles
Smooth muscles
(i)Multinucleated.
Uninucleated;
(ii)Striated/stripped.
Not striated/not stripped;
(iii)Long(muscles)fibres.
Short(muscle)fibres;
(iv)In blocks/cylindrical(in shape)
Spindled shaped.
Any two 2x1 = 2mks
16.(It facilitates the) reabsorption of useful substances in the kidney tubules into the blood stream;
- (It facilitates the) absorption of digested food from the gut into the blood stream;
- (It helps in the) movement of waste products from body into the blood stream/excreation of waste products
from the body cells into the blood stream;
(Any first two correct 2x1 = 2mks)
17.
Beneficial characteristic are retained/ because;
(i) New offspring are identical to the parent;
(ii) Organism matures faster;
(iii) It does not depend on population/fertilization/fruit and seed dispersal;
(iv) New plants obtain nourishment from their parent plant/ hence they can survive temporarily during unstable
environmental conditions;
(Any first three correct 3x1 = 3mks)
18. a) Entamoeba histolytica; (rules of Binomial nomeclacture followed)
(1mk)
b)
(i) Proper (sanitary) disposal of faeces and urine/use of deep pit latrines/flash toilets for disposal of faeces and
Urine;
(ii) All drinking water boiled/chemically treated to kill the eggs/miracidia/cercariae;
(iii) People should not bath/swim in water infested with snails;
(iv) People should wear protective shoes/water proof shoes/gumboots when walking in waters infested with
snails/swampy areas;
(v) Spray water infested with snails with molluscicides;
(Any first three correct 3x1 = 3mks)
19. (a) (i)Trachea; (1mk)
(ii)Diaphragm; (1mk)
Reject wrong spelling
(b) The ballons will inflate;There will be an increase in volume and a decrease in pressure in the bell jar; and air
will fill the balloons;/Air enters the balloons;
(Total 3mks max... 2mks)
20. (a) A situation where organisms have homologous structure/structure with common embryonic origin; which is
modified to perform different function; to adapt organism to different ecological riches/habitats/due to
exploitation of different ecological riches/habitats;
(b) It involves combining different breeds of species; resulting to Hybrid vigour/the offspring are better adapted
than their parents/Heterosis. (2mks)
21. (a) Sweepnet/insect net;
(1mk)
(ii) Pooter;
(1mk)
(b) (i) Unicellular, others colonial/some thalloid;
(ii) Are mobile; moving by pseudopodial/cilia/flagella;
(iii)Some are heterotrophic while others are autotrophic;
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Biology paper 1 ms
Any first two correct
(2x1 =2mks)
22. (a) Luteinising hormone; (reject Lh/wrong spelling) (1mk)
(b) -Increasing progesterone; inhibits follicle stimulating hormone; from
-Stimulating the maturation of another graafian follicle;
-Stimulating hormone;
23.Water vapour accumulates in stomatal pits making the environment around the stomata humid; this lowers the
saturation deficit;(hence less water is lost into the atmosphere)
24. (a) Prophase I ;(Reject wrong spelling/prophase 1/i)
(b) Recombination of genes; leading to variation;
(2mks)
25 (a) Herbivorous; (reject t herbivore)
(1mk)
(ii) Lack of canines/ presence of diastema ; lack of incisors on the upper jaw/has horny pad; (1mk)
a (ii) tied to (i)
(b) Vitamin B12 /Cobalamine; (1mk)
26. (a) Blood flow at a higher pressure; (since the heart pumps it twice)
- Blood flow faster to the tissues; (any one correct 1mk)
(b)-Numerous to increase surface area for exchange of materials;
-In close contact with the tissues/cells to ensure that every cell is well supplied with nutrients.
-Thin walled/one cell thick walled/thin Epithelium for faster exchange of materials;
-Narrow lumen to ensure that blood cells have to pass through it inn single file/to enhance ultrafitration;
(any two correct 2x1 = 2mks)
27. (a) Abscisic acid; (reject wrong spelling/AbA)
(1mk)
(b) - Thin walled; numerous mitochondria;
-Dense cytoplasm;
- No vacuoles;
-Small in size; (any first two correct 2x1 = 2mks)
28.
It protects the inner delicate tissues;
- It prevents dehydration or desiccation;
- Provide a surface for attachment of muscle; (which are essential for movement).
(any first two correct 2x1 = 2mks)
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