Mastering KCSE Biology with Comprehensive Topical Questions and Answers
K.C.S.E Biology Q & A - MODEL 2012PP1QN13
State three factors that affect the rate of diffusion.
answers
Temperature; surface area; distance that particles have to travel; diffusion/concentration gradient; size/density of particles; surface area to volume ratio; thickness of membrane; medium of diffusion
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K.C.S.E Biology Q & A - MODEL 2012PP1QN12
Why is it recommended to keep the stage of the microscope dry?
answers
Name the part of a light microscope used to bring an image of a specimen into sharp focus.26/6/2020
K.C.S.E Biology Q & A - MODEL 2012PP1QN12
Name the part of a light microscope used to bring an image of a specimen into sharp focus.
answer
K.C.S.E Biology Q & A - MODEL 2012PP1QN10
What is meant by the term irritability?
answers
K.C.S.E Biology Q & A - MODEL 2012PP1QN07
The diagram below represents a set-up that students used in an investigation.
​(a) Name the physiological process that was being investigated.
(b) State the role of potassium hydroxide in flask K. (c) Account for the observation in boiling tube L and flask N. L . N
answers
​(a) Respiration/aerobic respiration;
(b) Flask K Potassium hydroxide removes Carbon IV Oxide from atmospheric air; (c) L - Lime water remains clear because Carbon (IV) Oxide has been removed; Flask N lime water forms a white precipitate because the respiring cockroaches produce Carbon (IV) Ovide; K.C.S.E Biology Q & A - MODEL 2012PP1QN04
In an investigation, a student extracted three pieces of paw paw cylinders using a cork borer.
The cylinders were cut back to 50 mm length and placed in a beaker containing a solution. The results after 40 minutes were as shown in the table below.
​(a) Account for the results in the table above.
(b) What would be a suitable control set-up for the investigation?
answers
​(a) The solution was hypotonic/less concentrated compared to the cell sap of pawpaw cylinder cells;
The tissue/cells gained water by osmosis; becoming turgid/longer/stiff; (b) Pawpaw cylinders of the same size/length; placed in an isotonic solution; Boiled potato cylinders of the same size; placed in a similar solution; K.C.S.E Biology Q & A - MODEL 2012PP1QN03
The figure below is a fine structure of a generalised animal cell as seen under an electron microscope.
​(a) Name the parts labelled A and B.
A B (b) How is the structure labelled B adapted to its function?
answers
​(a) (i) A - nucleopore;
B - Rough Endoplastic Reticulum; (b) Surface covered with ribosomes; for protein synthesis; Has interconnected channels: for transportation of proteins; K.C.S.E Biology Q & A - MODEL 2012PP1QN02
The diagram below represents a certain organism collected by a student at the sea shore.
​(a) Name the class to which the organism belongs.
(b) Give three reasons for your answer in (a) above.
answers
K.C.S.E Biology Q & A - MODEL 2012PP1QN01
How does nutrition as a characteristic of living organisms differ in plants and animals?
answers
K.C.S.E Biology Q & A - MODEL 2011PP2QN06
Explain how the osmotic pressure in the human blood is maintained at normal level.
answers
K.C.S.E Biology Q & A - MODEL 2011PP2QN01
The set-up below illustrates a procedure that was carried out in the laboratory with a leaf plucked from a green plant that had been growing in sunlight.
(i) What was the purpose of the above procedure?
(ii) Give reasons for carrying out steps A, B and C in this procedure. A B C (iii) Name the reagent that was used at the step labelled D. (iv) State the expected result on the leaf after adding the reagent named in (iii) above.
ANSWERS
​(i) - Testing a leaf for the presence of starch;
(ii) - A - kill the leaf/break down cells/stop enzymatic activity; B - Removal of chlorophyll; C - Soften leaf/makes leaf less brittle; (iii) Iodine solution; (iv) Areas where starch is present stain blue/blue black;
K.C.S.E Biology Q & A - MODEL 2011PP1QN18
State two functions of saliva.
answers
K.C.S.E Biology Q & A - MODEL 2011PP1QN17
The diagram below represents part of the human digestive system.
(a) Name the organs labelled L and M.
L M . (b) (i) Name the substance produced by the organ labelled K. (ii) State the function of the substance named in b(i) above.
answers
​.(a) L - Duodenum;
M - Pancreas; (b) (i) Bile; (ii) Emulsification/emulsifies fats; (iii) Provides alkalinic medium for enzyme action. (iv) Neutralizes acidic chyme. K.C.S.E Biology Q & A - MODEL 2011PP1QN15
Give reasons for carrying out the following procedures when preparing temporary wet mounts of plant tissues.
(a) Making thin plant sections. (b) Adding water on the plant section. (c) Placing a cover slip over the plant section.
answers
K.C.S.E Biology Q & A - MODEL 2011PP1QN13
State two functions of carbohydrates in the human body.
answers
K.C.S.E Biology Q & A - MODEL 2011PP1QN12
The diagram below represents a certain organism.
​State the phylum and class to which it belongs.
Phylum Class
answers
​Chordata; . Aves; .
K.C.S.E Biology Q & A - MODEL 2011PP1QN11
State the functions of the following parts of a light microscope.
(a)Fine adjustment knob. Stage.
answers
(a)Moves the body tube through smaller distances to bring the image/specimen/object into sharper focus;
(b)Platform where specimen (on slide) is placed; K.C.S.E Biology Q & A - MODEL 2011PP1QN09
The diagrams below illustrate the organs of some flowering plants.
​State the classes of plants to which each belong.
A B
answers
​(a) Dicotyledonae;
(b) Monocotyledonae;
K.C.S.E Biology Q & A - MODEL 2011PP1QN08
State three characteristics of the class crustacea.
answers
K.C.S.E Biology Q & A - MODEL 2011PP1QN07
The diagrams below show an experimental set-up to investigate a certain process in a plant tissue.
Explain the results obtained after 30 minutes.
answers
K.C.S.E Biology Q & A - MODEL 2011PP1QN04
State one use for each of the following apparatus in the study of living organisms.
(a) Pooter (b) Pitfall trap
answers
(a) Sucking small insects/animals;
(b) A trap into which small animals fall and get trapped;
K.C.S.E Biology Q & A - MODEL 2011PP1QN03
Give three reasons for classifying organisms.
answers
​(i) Identify similarities and differences between organisms;
(ii) Organize scientific knowledge in an orderly system; (iii) Monitor emergence, presence and disappearance of organisms in and from the earth; (iv) Grouping organisms for easy stud
K.C.S.E Biology Q & A - MODEL 2011PP1QN02
Name two dental diseases.
answers
K.C.S.E Biology Q & A - MODEL 2010PP2QN06
In an experiment to investigate a certain physiological process, a boiling tube labelled A and a test tube labelled B were covered with cotton wool. The two tubes were simultaneously filled with hot water and fitted with thermometers. The experimental set-up was as in the diagrams below.
​Temperature readings were taken at the start and after every two minutes for twenty minutes. The results were as shown in the table below.
(a) Using the same axes, draw graphs of temperature against time.
(b) (i) Work out the rate of heat loss in the boiling tube labelled A and test-tube labelled B between the 5th and 15th minutes. A B (ii) Account for the answers in (b) (i) above. (iii) How does the explanation in (b) (ii) above apply to an elephant and a rat? (c) (i) State the role of the cotton wool in this experiment. , (ii) Name two structures in mammals that play the role stated in (c) (i) above. (d) State three advantages of having constant body temperature in mammals.
ANSWERS
(b) (i) A: 56—48.5 7.5C
7.5C/10 Minutes ; = 0.75C Per Minute; ±0.05 B: 48-34=14C 14C/10 Minutes ; =1.4C Per Minute; ±0.05 (ii) B has a larger surface area to volume ratio; making it to lose heat to the surrounding faster; (the converse is true) (iii) A rat has larger surface area to volume ratio compared to an elephant; making the rat to lose heat at a faster rate than an elephant; (c)(i) Insulation/insulate against heat loss; (to surrounding); (ii) Subcutaneous fat layer / adipose tissue; Fur / hair; . (d) Are active always; (even under very cold conditions) Are able to escape from predators/search for mates/food; (because they are active always) Can survive in a wide variety of habitats: (both cold and hot) |
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