K.C.S.E Biology Q & A - MODEL 2019PP2QN06
The table below shows the rate of product formation for two enzymes, H and J over a range of pH values
(a) On the same axis, plot graphs of the rate of product formation against pH.
GRAPH PAPER (b) Account for the rate of product formation for enzyme H between: (i) pH 1.0 and 3.0 (ii) pH 3.0 and 7.0. (c) From the graph, determine: . (i) the pH value at which the rate of product formation of the two enzymes was the same (ii) the value of the rate of product formation for enzymes H and J at the pH value stated in (c)(i) above (iii) the optimum pH value for enzyme J (d) State one variable that may lead to the change in the optimum rate of product-formation of the two enzymes. (e) Suggest with a reason, the likely part of the human alimentary canal where enzyme H would be found.
answers
​(b) (i) Rate of product formation increases with the increase in pH to the optimum then decreases;
pH 5 is the optimum pH value for activity of enzyme H; between pH 1 and 2 enzyme H/enzyme molecules are activated; Between pH 2 and 3 enzyme H (enzyme molecules) are denatured/destroyed; (. Enzyme is inactivated/ less active for denatured (ii) Rate of product formation (sharply) decreases with increase in pH; Enzyme H is (not formed by increase in pH hence is denatured); No product forms above pH 4.0 to 7.0; because all enzymes (enzyme molecules) are denatured; (c) (i) 4.0 (ii) 15.0 mg/hr (iii) 7.0 (d) -Temperature -Substrate concentration; -Enzyme concentration; -Cofactors -Co-enzymes -(Enzyme) inhibitors (e) Stomach; Acidic medium/Low pH
K.C.S.E Biology Q & A - MODEL 2019PP2QN03
State one importance of irritability to living organisms.
answers
​(a) Enable living organisms to avoid dangerous/harmful/hash climatic environmental conditions; Enable living organisms obtain/access favourable environmental conditions (light, water, oxygen,
K.C.S.E Biology Q & A - MODEL 2019PP1QN24
Plasmodium vivax and Plasmodiuin ovale are transmitted by a mosquito. State with a reason whether the two organisms can interbreed.
answers
​(a) they can interbreed; because they belong to the same genus;
They cannot interbreed; because they do not belong to the same species.
K.C.S.E Biology Q & A - MODEL 2019PP1QN21
Make a diagram of a simple, bibbed leaf with a serrated margin.
answers
K.C.S.E Biology Q & A - MODEL 2019PP1QN19
Below is a diagram of the human digestive system.
​(a) Label with Y on the diagram where enzyme amylase is produced.
(b) Besides the digestive role, explain one other function of the part labelled H.
answers
(b) Endocrine function/secrets (insulin/ glucagon) hormones; responsible for blood sugar regulation;
K.C.S.E Biology Q & A - MODEL 2019PP1QN18
Name the type of tooth in carnivores mainly used for piercing and killing of preys.
answers
K.C.S.E Biology Q & A - MODEL 2019PP1QN11
Explain each of the following physiological observations:
(a) sportsmen release little, concentrated urine at the end of a strenuous exercise (b) a rabbit has a higher oxygen demand than a camel
answers
​(a) during /after the exercise one sweat ; (profusely to cool the body/eliminate some nitrogenous (wastes) a lot of water is lost through this ; one is dehydrated ;(the little) water that is left in the body system (further) selectively reabsorbed in the kidney tubules (resulting in less but concentrated urine;)
(b) a rabbit has a higher surface area to volume ratio/ smaller in size hence has a bigger surface area exposed to heat loss to the environment/ lose heat faster/ its more active than the camel; hence need more oxygen to(aerobically) respire (to synthesize the needed energy to support its activity /lifestyle; K.C.S.E Biology Q & A - MODEL 2019PP1QN09
Below is a photograph of Brassica oleracea, Sukuma wiki leaf.
​(a)State two observable features that adapt the leaf to gaseous exchange.
(b) Explain the relationship between photosynthesis and aerobic respiration within the leaf.
answers
​.(a) broad leaf blade /lamina; that expose more stomata for gaseous exchange; acc broad leaf alone
(b) photosynthesis (within the leaf in the presence of light energy) yield simple carbohydrates /glucose /sugars which form the main substrate during aerobic respiration (producing energy (ATP) During the process of respiration carbon iv oxide produced is intern used as a raw material in photosynthesis; During photosynthesis water is broken down yielding oxygen which is needed/ used in (cellular) (aerobic respiration);
K.C.S.E Biology Q & A - MODEL 2019PP1QN07
Distinguish between chemical and mechanical digestion.
answers
K.C.S.E Biology Q & A - MODEL 2019PP1QN04
In investigating a certain physiological process, students set up the apparatus as shown below and made the observations after 30 minutes as illustrated.
​(a) Name the physiological process being investigated.
(b) Account for the observation made at the end of the experiment. (c) State the likely identity of G.
answers
. (a) osmosis
(b) solution E is hypertonic/ had more solute molecules compared to solution F; solution F hypotonic to solution E; by osmosis water molecules move through the semi- permeable membrane G (from solution F to E); hence decreases in volume of F/ increased solution E; (c) semi permeable membrane /visking tubing /slice of potato /pawpaw (any other permeable plant tissue) pig bladder/cellophane paper/dialysis membranes. K.C.S.E Biology Q & A - MODEL 2019PP1QN03
The diagram below illustrates a specialised cell obtained from a certain tissue.
​(a) Name the cell.
(b) State two ways in which the cell is structurally adapted to its function.
answers
(a) nerve cell/motor neuron; acc neuron
(b) longer axon to transmit impulses/delivers action potential along way; has numerous dendrites for receiving/delivering /transmitting impulse; myelin sheath for faster transmission of impulse/insulation of axon; Schwan cell for secretion of myelin sheath; node of ranvier to enhance speed of transmission of impulse; cell body has nucleus for controlling nerve impulse transmission.
K.C.S.E Biology Q & A - MODEL 2019PP1QN02
Explain why the bat is classified as a mammal yet it flies.
answers
K.C.S.E Biology Q & A - MODEL 2019PP1QN02
Besides venation, state two other external characteristics of leaves that can be used to classify plants.
answers
(a) shape of the leaf blade/lamina(broadness or narrowness); leaf margin(smooth or serrated); leaf apex(pinnate dot rounded);leaf arrangement; leaf colour ; (leaf texture(smooth or rough); leaf type(simple or compound)leaf sheath/petiole(absence or presence)
(b) has mammary gland; body covered with fur/hair; gives birth/does not lay eggs; has external ears/pinnae; has seven cervical vertebrae; has sweat glands; heterodonts/four types of teeth K.C.S.E Biology Q & A - MODEL 2019PP1QN01
Name the characteristic of living organisms illustrated by each of the activities described below:
(a) Dressing heavily (b) Bursting of the sporangium in the Rhizopus sp
answers
K.C.S.E Biology Q & A - MODEL 2018PP2QN08
Describe what happens to a meal rich in proteins along the alimentary canal from ingestion to egestion.
answers
​The meal is ingested through the mouth; (In the mouth), it is chewed/masticated (by teeth); to reduce/break it into smaller particles; mixed with saliva (from salivary gland);
The food is then rolled (by the tongue) into boluses; and pushed down into the oesophaghus/swallowed; The boluses move by peristalsis (into the stomach); Constant contractions/relaxations of the stomach walls mix the food, (giving rise to chime); Presence of food in the stomach further stimulates production of gastric juice; which contains pepsinogen; and rennin/chymosin; Pepsinogen is activated to pepsin; by hydrochloric acid; (contained in the gastric juice). Pepsin breaks down proteins to peptides; Rennin converts/coagulates the protein, caseinogen; in milk to casein; (which is abundant in young children). It is then pushed into the duodenum (through the pyloric sphincter); Pancreatic juice in the duodenum contains trypsin; which digests proteins into peptides; (secreted in an inactive form, trypsinogen) In the ileum, intestinal juice/Succus enfericus is secreted; It contains peptidase enzymes; which breaks down polypeptides into amino acids; It also contains polypeptidase enzyme; which breaks down peptides to amino acids,completing the process of digestion of the proteins; The amino acids are absorbed into the bloodstream/pass through the epithelia of the villi, and the capillary walls into the blood-stream; by active transport; The undigested/indigestible proteins/food substances pass through to the colon/large intestines; where water is absorbed; leaving a semi-solid waste material being passed on to the rectum; then out through the anus (as faeces); |
TOPICSFORM 1
Form 2
Form 3
Form 4
ARCHIVES
CATEGORIES
Categories
All
RSS FEEDS
|
RSS Feed
Download our Android App
|
|
|
Primary Resources
College Resources
|
Secondary Resources
|
Contact Us
Manyam Franchise
P.O Box 1189 - 40200 Kisii Tel: 0728 450 424 Tel: 0738 619 279 Tel: 0763 450 425 E-mail - sales@manyamfranchise.com |