K.C.S.E Biology Q & A - MODEL 2015PP2QN08
How is a mammalian heart structurally adapted to its function?
K.C.S.E Biology Q & A - MODEL 2015PP1QN03
.An individual is of blood group B positive.
(a) Name the antigens in the individual’s blood.
(b) Give the reason why the individual cannot receive blood from a blood group A donor.
(a) (Antigen) B; Rhesus (antigen)/Rhesus factor/Antigen D
(b) Has antibody a in the blood plasma of the recipient and will correspond with antigen A in the donor’s blood, hence there will be antigen antibody reaction/agglutination.
K.C.S.E Biology Q & A - MODEL 2014PP2QN02
The diagram below illustrates the role played by red blood cells in the transportation of carbon (1V) oxide.
(a) Other than the carbon (IV) oxide transportation in the red blood cells, name the other form of carbon (1V) oxide transportation in humans.
(b) (i) Name substance F
(ii) Name the enzyme marked C and state its role in the reaction.
(c) Explain why transportation of carbon (1V) oxide in red blood cells is advantageous.
(d) Explain the role of calcium ions in blood clotting.
(a) Carbonic acid/carbaminohaemoglobin/hydrogen carbonate;
(b) (i) Water;
(ii) Carbonic acid;
Role: catalyses reaction between carbon IV oxide and water to form (weak) carbonic acid;
(c) Prevents accumulation of acidity/maintains pH of blood since hydrogen ions combine with haemoglobin to form Haemoglobin acids;
Faster; due to the catalytic effect of carbonic anhydrase;
(d) Activates thromboplastin; thrombokinase to neutralize heparin/convert prothrombin to thrombin;
K.C.S.E Biology Q & A - MODEL 2014PP1QN24
The table provided shows the transportation of substances in the human body.
Name the substances represented by
M - lungs;
N - Urea, ammonia. ;
P - Digested food. water; mineral ions;
K.C.S.E Biology Q & A - MODEL 2013PP2QN07
Describe the process of blood clotting in human beings.
When a blood vessel is cut/injured platelets/thrombocytes/damaged tissue/wound is exposed to the air: they release thrombokinase/thromboplastin ; an enzyme that activates the conversion of prothrombin: to thrombin: in the presence of calcium ions: vitamin K/ phylloquinone ; is needed for the formation of prothrombin; Thrombin converts (soluble blood protein) fibrinogen ; into (the fibrous form) fibrin; which forms a mesh / network across the wound: The clot so formed prevents excessive bleeding: and entry of disease agents/pathogens/micro-organisms/microbes;
K.C.S.E Biology Q & A - MODEL 2013PP1QN24
Explain three protective functions of mammalian blood.
K.C.S.E Biology Q & A - MODEL 2013PP1QN11
State the advantage of possessing blood group AB.
K.C.S.E Biology Q & A - MODEL 2012PP1QN28
State two differences between open and closed circulatory systems.
Blood flows in haemocoel Blood confined in vessels;
sinuses/body cavity directly
in contact with cells
Blood flows at low pressure Blood flows at high pressure;
Blood lack pigments Blood has pigments for oxygen and
Carbon (IV) Oxide transportation
K.C.S.E Biology Q & A - MODEL 2012PP1QN23
Name the strengthening materials found in the following support tissues:
K.C.S.E Biology Q & A - MODEL 2012PP1QN11
State two ways in which heart muscles are special.
K.C.S.E Biology Q & A - MODEL 2011PP2QN07
Explain how structural features in terrestrial plants affect their rate of transpiration.
Plants in arid, semi-arid and desert habitats have leaves covered with thick/waxy cuticles; that are waterproof/impermeable to water; allowing for reduced rate of transpiration; Sunken stomata; in some desert/semi arid areas plants have water vapour accumulating in the pits; reducing rate of transpiration (as the moisture in the pit is carried away by wind.) Most plants have few or no stomata on the upper surface of leaf; the fewer the stomata the less the water lost from the plant. Some plants have small stomata/stomatal size decrease when guard cells are flaccid; thus reducing transpiration rate. Plants with small/folding leaves; expose less surface area; hence reduce the rate of transpiration. Leaves with shinny surfaces; reflect light resulting
reduced leaf temperatures; thus reducing the rate of transpiration. Some plants have leaves covered with hairs/scales; which trap a layer of moisture; the leaf surface reducing rate of transpiration. Mesophyte have a thin layer of cuticle; to facilitate high transpiration rate; brad lenses exposing large area to transpiration; Many stomata on both leaf surfaces provide many apartunes to enhance transpiration.
K.C.S.E Biology Q & A - MODEL 2011PP2QN03
Describe how oxygen in the alveolus reaches the red blood cells.
K.C.S.E Biology Q & A - MODEL 2011PP1QN25
State one economic importance of each of the following plant excretory products.
K.C.S.E Biology Q & A - MODEL 2011PP1QN16
What is the role of blood platelets in the blood clotting process?
K.C.S.E Biology Q & A - MODEL 2011PP1QN16
Describe the condition known as varicose veins.