KNEC KCSE Biology Paper 1 Question Paper / 2015 KCSE Tharaka South Joint Examination

− Two names i.e ist genus and 2nd species
− Genus names start with capital letter while species start with small letter.
− Both names are written in intalics when printed / underlined when typed or handwritten. Mark any 2 x 1 = 2 marks

a). Nucleus 1 mk
b). Nuclear membrane / pore 1mk
c). Centriole 1mk

a). i). Region of elongation / rapid growth in root / radical 1mk
ii).

iii). To provide water / moisture for germination 1ml
b). i). oxygen – for oxidation of food to provide energy for germination 1mk
ii). Cotyledons – store food necessary for germination / protect plumule 1ml

− enzymes – thrombin 1mk
− thromboplastin (thrombokinase) 1mk
− metal ion – calcium ions 1mk

a). Chitin 1mk
b). Lignin 1mk

− Gill filament are thin / cell thick to facilitate faster / rapid diffusion of respiratory gases 1mk
− The surface of the gill filaments are moist to facilitate dissolution of the repiratory gases 1mk
− The gill have numerous rakers that filter food / soild particles that may damage the gill filaments
− The gill is highly vascurised to ensure efficient transport of respiratory gases Mark any 3 – @1mk = 3 mks

a).
i). More active sites of enzymes available for a large number of molecules of substrate hence increase in the rate of reaction
(rapid or fast increase in the rate of reaction)
ii). B and C
enzymes / substrate are in equilibrium / all active sites are occupied hence rate of reaction is constant
b). Raising concentration of enzymes

a). So that they could be destarched / use up all the stored starch
b). No starch in the plant
the NaOH solution absorbed carbon (IV) oxides from the air hence no photosynthesis occurred to form starch

− myelin sheath
− Nodes of ranvier

a). Protoctista 1mk
b). Phylum – arthropoda; rej Arthropods
class – arachnida rej Arachnids

a). A – Neural Spine
B- centrum
b). For attachment of abdominal muscles

a). Nastic /Haptonasty Phototaxis
b). Positive Phototaxis
c). Negative phototaxis

a). – selfig / self fertilization as in plants
– test cross / back cross
b). Haemophilia is a sex – link characteristic which is only carried by the X chromosome and a father can only donate x-
chromosome to his daughter but not son
c). Xh
Y

a). Gill
b). Creates a large surface area for maximum gaseous exchange
c). Large and curved to provide large surface for attachement of numrtous gill filaments bony / rigid to offer support

a). high chance of survival since zygote is highly protected in the body.
High chances of fertilization
b). Most of the excess amino acids are used in the development and growth of the foetus thus less amino acid are delaminated

a). R – sieve pore
S – cytoplasmic strand cytoplasm filaments rej. proto plasmic strad)
Cell labeled T – companion cell
b). Translocation (L is tied with structures)

Natural immunity is inherited / transmitted from parent to offspring
Acquired immunity is developed after suffering from a disease / through vaccination
Accept inmate / inborn for natural immunity rej. Born with it

a). Lamarckia
Inheritance of acquired characterists / environment induces production of inheritable character which is then inherited
Darwinian
Inheritance of genetically acquired characteristics / character happends to appear spontaneously which then gives
advantage of organisms therefore better – adaptable characters are then inherited by natural selection
b). Are structured greatly reduced in size and therefore not used to function acc. Third digit og wing or bird
– Halteres in flies
– presence of hind limb / (buds) in python
– Human ear muscles
Example
Human appendix / kiwi (flightless bird) with reduced wings / vestiugial wings in flies human hair / presence of hind limbs in
python, reduced pelvic girdle of whale

a). Glucagon
b). Antidiuretic hormone /ADH/vasopresin any first one

i). Alcohol
ii). Lactic acid 2 mks

More water will enter the amoeba by osmosis rate of water enter the amoeba by osmosis rate of water discharged by contractile vacuole will increase more contractile vacuoles formed

a). The ability of microscope to separate images of objects that lie close to one another
b). Stains / colour parts of the cell making it more visible / clear

− Plants are able to store the wastes in their bodies in non-toxic forms
− Plants are stationary and therefore less active hence realse less toxic wasted compared to plants which produce a lot
− Plants utilize simple inorganic substance to make their foods in amount required by the body hence less wastes while animals consume complex compounds whose breakdown releases more toxic wastes

Sweat produced does not evaporate due to high humidity and the body does not cool hence more sweat produced leading to accumulation 2mks

a). – generative nucleus 1mk
Pollen tube / tube nucleus 1mk
b). A kind of fertilization in which the male nucleus decides into two male nuclei. One of which fertilizes the functional egg
forming a zygote while the other fuses with the polar nuclei to form a primary endosperm nucleus

a). Helps in absorption of some products of digestion from alimentary canal into blood stream
b). Oxygen concentration / amount t of oxygen
− Change of temperature
− substrate / glucose concentration
− Enzyme inhibitors / metabolic poisons Any first correct two