Biology Paper 1 Marking Scheme
KCSE CLUSTER TESTS 27
Biology Paper 1
Biochemistry
1 marks
Light of optimum intensity enhance photosynthesis in phytoplanktons/green plants thereby encouraging their multiplication, this leads to increase in fish population since they have abundant food, low light intensity reaches photosynthesis is phytoplanktons/green plants thereby lowering their multiplication; thus reducing fish population is through death due to starvation
3 marks
i) Leads to the emergence of new organisms/species/animals/plants/flora/fauna.
ii) Enable the well/most adapted organisms to live up to reproductive age/survive/ and pass their characteristics to their offspring. iii) Scarcity of resources / limitation of resources can name the resources e.g. food/breeding
mates/shelter.
3 marks
ADH increases the permeability of kidney tubules/nephrone to water; hence retention of water in the body; OWTTE.
2 marks
a) Golgi body /apparatus b) Secrete enzymes; produce lysosomes; transportation of hormones, modification of carbohydrates and proteins/ glycoprotein’s, packaging of carbohydrates and glycoproteins Mark the first three
3 marks
a) Chordata (1mrk)
b) Have mammary glands
Body covered with fur/hair
Have pinnae
3 marks
3 marks
i) production of root hairs
ii) Production of lateral roots
iii) Protect apical meristem/enable the root penetrate the soil
3 marks
nitrogen – making of cell wall, magnesium ;
3 marks
a) interphase
b) 46 (chromatids
2 marks
a) Motor neurone/nerve cell b) Schwann cell c) Enhance the transmission of (nerve) impulses/speed up the transmission of impulses.
3 marks
New born babies lose more heat per unit weight due to a larger surface area to volume ratio; this results to higher rate of oxygen consumption during respiration to maintains their body temperature; higher heartbeat count increases; blood circulation to supply oxygen to tissues and remove carbon (iv) oxide and other wastes
3 marks
Absorb water by osmosis, hence become turgid, presence of collenchyma/sclerechyma
3 marks
a) intermttent growth
b) Moulting/ecdysis
c) Ecdysone
3 marks
2 marks
Blood has no antigens; do not cause agglutination with the other antigens of other blood groups
2 marks
Alveoli/alveolus
2 marks
. a) Glucose Ethanol + carbon (iv) oxide + energy /C6H1206 2C2H5OH + CO2 + energy (must be balanced)
b) Manufacture of ethanol/biogas/baking (bread
3 marks
a) Water vapour lost by transpiration will cause the cobalt chloride paper to turn pinks
. b) To prevent water vapour in the atmosphere from getting into contact with the cobalt chloride paper
3 marks
Presence of villi/micro villi, long/supplied with blood capillaries/presence of lacteals presence of thin epithelium
3 marks
a) Trichomonas vaginalisis Schistosoma mansoni/ haematobium/Japonicum.
b) Malaria
3 marks
in bright light/high intensity, the circular muscles contract and radial muscles relax, the pupils becomes smaller, in dim light/ low light intensity circular muscles relax, and radial muscles contract and the pupil becomes bigger/wider
3 marks
a) herbivorous
b) Lacks upper canine and incisors
Presence of diastemia
3 marks
a) Conduction Radiation
b) Protection/ from desiccation/drying/reduce loss of moisture/water from the body
3 marks
in bright light/high intensity, the circular muscles contract and radial muscles relax, the pupils becomes smaller, in dim light/ low light intensity circular muscles relax, and radial muscles contract and the pupil becomes bigger/wider
2 marks
in higher attitude the atmospheric pressure is low/air is less premed; there is low concentration of oxygen and carbon (iv) oxide in lower altitude atmospheric pressure is high/air more premed there is high concentration of oxygen and carbon (iv) oxides
3 marks
b) Mice, lizard, snakes
c) Most/some plants will die/dry
Some/all / most organisms will starve to death.
Some/all/ some organisms may migrate Mark one
3 marks
Triceps contract and biceps will relax
3 marks
3 marks