TRANS-MARA WEST DISTRICT EXAM-2014
BIOLOGY PAPER 1
MARKING SCHEME
1.
Photolysis/provides energy required for splitting water molecules into hydrogen ions and oxygen
gas;
(1 x1 = 1mk)
2.
- Formation of the harmone thyropine;
- Nerve impulse transmission;
3.
(i)
ultra filtration
(1mk)
(ii)
Reabsorption;
(1mk)
4. (a) (i)
Manufacture/synthesis of ribosomes;
(1mk)
(ii)
Transport of lipido
(1mk)
(b) Golgi bodies/Golgi apparatus;
(1mk)
5.
(i)
For attracting and trapping small animals including rats
(1mk)
(ii)
For keeping collected specimen;
(1mk)
(iii) For catching crawling animals;
(1mk)
6.(a) Involves the movement of water molecules from a region where they are highly concentrated to a
region where they are lowly concentrated through a semi-permeable membrane.
(1mk)
(b) - Reabsorption of sugars and some salts by the kidney;
- Absorption of digested food from alimentary canal of animals into the blood stream;
- Excretion of waste products from body cells;
- Accumulation of substances into the body to affect osmotic imbalance in acid and saline
environment.
(1 x 2 = 2mks)
7.(a) Alternative forms of a gene controlling a particular characteristic
(1mk)
(b) A dominant gene expresses itself in both its homozygous and heterozygous states; while a recessive
gene can only express itself in homozygous state.
(1 x 2 = 2mks)
8.(a) (i)
Root cap;
(1mk)
(ii)
Protects the root tip from mechanical damage/abrasive effects of the soil particles as it grows
(1mk)
(OWTTE)
(b) - They are small;
- They have dense cytoplasm
- They have thin membranes;
- They lack vacuoles;
(1 x 2 = 2mks)
9.(a) (i)
A natural unit composed of a biotic and biotic factors whose instruction lead to a self
sustaining system;
(1mk)
(ii)
The maximum population of a species that a particular habitat can support; (1mk)
Acc;-Total no. of organisms a particular habitat/area/ecosystem/region/environment can support
without depleting the resources;
Total no. of population of a species in a given habitat/area/ecosystem/environment can support
without depleting the resources.
(b)
Floating hydrophytes have numerous and large stomata on the upper epidermis;
- Have aerenchyma tissues in their stems/leaves/roots to store air and for gaseous exchange;
- Those in swampy environments have pneumatophods breathing roots; (2 x 1 = 2mks)
10 (a) (i) Thromboplastin/thrombokinase;
(1mk)
(ii) Thrombin;
(1mk)
(b) Activates conversion of inactive prothrombin to active thrombin; (1mk)
(i) Blood groups;
(1mk);
(ii) Set-u A (1mk)
11.
(a) (i) Tropism/tropic response;
(1mk)
(ii) The side brushed with IAA increased concentration of this hormone (IA; This lead to
increased cell elongation/growth hence a growth harvature away from the brushed side;
(OWTTE)
(2 x1 = 2mks)
1
12. (a) Deamination;
(b) (i)
Glycogen;
(ii)
Glucose;
(1mk)
(1mk)
(1mk)
13.(a) Homologous structures have a similar embryonic origin but modified to perform different function;
Analogous structures have different embryonic origin but modified to perform similar function;
(2 x 1 = 2mks)
(b) That a phenotypically acquired characteristics can be transmitted to the offspring by their parents;
(1mk)
14 (a) - Open system
- Closed system
- Blood flows at low pressure
- Blood flows at high pressure
- Blood flows in haemowel/sinuses
- Blood is confined in vessels/closed vessels/body
body cavity/coacom /directly in
vessels;
contact with cells.
- Blood lacks pigments for
- Blood has pigment for transport of O2 and Co2
transport of O2 and Co2
(2 x 1 = 2mks)
(b) - Can contract continuously without fatigue;
- Their contraction is stated by the muscles themselves (and not by the nerves/myogemic);
(2 x 1 = 2mks)
15.(a) Vasodilation/blood flows on the surface;
- Hair lies on the skin/hair lies flat on the skin;
- Metabolic rate decreases;
- Sweating;
(2 x 1 = 2mks)
(b) It is long to increase surface area for reabsorption of water.
- It is lined with a network of capillaries to enhance reabsorption of water;
- It is u-shaped to bring about counter current multiplier effect/to concentrate salts in the medulla to
bring about reabsorption of water;
(2 x1 = 2mks)
16.(a) leads to the formation of larval utricle;
(1mk)
(b) (i)
Growth rate in rapid/fast/high and shed cuticle several times hence feed alot to have
(desired) energy;
(1mk)
(ii)
- Cells elongate before the cuticle harden;
- Some cell division take place;
(1 x 1 = 1mk)
17.
- Oxygen depletion due to excessive growth of aquatic plants leading to suffocation and death of
aquatic animals;
- Entrophication hinder light penetration affecting photosynthesis in submerged hydrophytes;
- Cause water surface blockage affecting navigation/fishing.
(3 x 1 = 3mks)
18.
- Having sexual (unprotected) intercourse with an infected person;
- Blood transfusion with infected blood;
- From infected mother to child during birth;
- Use of unsterilized, infected surgical instruments;
- Sharing cutting/piercing instruments with infected people;
(3 1 x = 3mks)
19.
- Arthropods are large multicellular organisms;
- Arthropods have jointed appendages;
- Arthropods body is covered by an exoskeleton;
- Arthropods have segmented bodies;
- Arthropods exhibited sexual reproduction with an internal fertilization. (3 x 1 = 3mks)
20.(a) (i)
Offers a large surface area for muscle attachment (1mk)
(ii)
Humerus;
(1mk)
Rej: Humerous or other wrong spellings for humerus
(b) - Cellulose
- Colenchyma tissue.
- Selerenchyma tissue.
2
- lignified xylem and tracheids;
21.(a) Anaerobic respiration
(1mk)
Rej: Respiration alone
(b) (i)
To expel all the dissolved oxygen;
(ii)
22.
23.
Glucose Enzyme
Acc C6H12O6
(2 x 1 = 2mks)
(1mk)
carbon (IV) oxide + Ethanol + Energy
2CO2 + 2C2 H5 OH + ATP;
- Natural active immunity;
- Artificial active immunity;
(1mk)
(2 x 1 = 2mks)
(i)
Funnel shaped to collect and concentrate sound waves into the external auditory meatus;
- In some animals its large and when flapped creates air currents lining about cooling effect
to the animals;
(1 x 1 = 1mk)
(ii)
Its thin and flexible to enable transformation of sound waves into vibrations
(1mk)
(iii) It’s coiled to offer a large surface area for the attachment of the sensory cells.
- Has numerous sensory cells to perceive sound vibrations.
- Has thin membrane that vibrates more increasing the intensity of sound vibrations;
- It’s filled with a fluid to enhance transmission of sound waves in it.
(1 x 1 = 1mk)
24.(a) Cerebrum;
(1mk)
(b) Nourishes the brain cells/supplies nutrients/removes metabolic wastes from brain cells.
- Acts as a shock absorbs to the CNS
(2 x 1 = 2mks)
25.
- Nasal cavity has hairs and mucus that trap solid particles and dust;
- Nasal cavity is well supplied with blood that warms and moistens incoming air.
- Has olfactory cells that are sensitive to smell;
(2 x 1 = 2mks)
26.
(a)
Budding;
(1mk)
(b)
(i)
Production of the male reproductive cell/gamete/sperm;
- Production of androgens/male hormones.
(1 x1 = 1mk)
(ii)
Fertilization takes place here/where fertilization occurs;
- Passage of the female gamete/fertilized ovum to the uterus.
(1 x1 = 1mk)
(iii)
passage of urine/sperms/semen;
(1mk).
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TRANS-MARA WEST DISTRICT EXAM