KNEC KCSE BIOLOGY TOPICAL QUESTIONS AND ANSWERS

K.C.S.E Biology Q & A - MODEL 2017PP1QN21

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN21

The photograph below represents a leaf obtained from a certain plant.

Account for the observations made if the leaf was tested for starch.

answers

Differences in distribution of chlorophyll/leaf is variegated; green patches would photosynthesize forming starch; giving blue-black colour with iodine solution unlike the regions without chlorophyll;

Comments

State three methods of fossil formation.

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN20

State three methods of fossil formation.

answers

i. Petrification/change into rock;
ii. Entire organism or parts preserved;
iii. Impressions (e.g. casts/moulds);

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN19

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN19

The table below shows the percentage concentration of certain substances in blood plasma, glomerular filtrate and urine in a human being at a particular time.

(a) Explain the likely impact on the composition of urine in case of the following:
(i) Vigorous physical exercises
(ii) a meal rich in proteins
(b) Name the processes responsible for:
(i) Presence of glucose in the glomerular filtrate
(ii) absence of glucose in urine

answers

a. i) Less water and urea; since sorne is excreted/eliminated through the skin (as sweat);
ii) increased amount of urea in the urine; due to deamination of amino acids (from proteins);
b. i) ultra filtration;
ii) Selective reabsorption;

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN18

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN18

Below are diagrams representing developmental stages of three different vertebrates.

(a) State the evidence of evolution illustrated by the vertebrates in the diagram.
(b) Suggest why the structure labelled J has been retained throughout the evolution of fish.
(c) State two major advantages evolution has given humans Over most of the other animals.

answers

Comments

How is the surface area increased in the mammalian small intestines?

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN17

How is the surface area increased in the mammalian small intestines?

answers

Presence of numerous villi/microvilli;
Being long;
Being highly coiled;

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN16

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN16

The following are text messages on a celiphone that represent gene mutation.

(a) Identify the type of gene mutation represented in each case
I
II
(b) State Mendel’s First Law.
(c) State two disadvantages of genetically modified plant products.

answers

a. I — Deletion;
II- Inversion;
b. The characteristics /traits of an organism are determined by internal factors/ genes (which occur in pairs). Only one of the genes can be carried in a gamete/ passed onto the next generation;
c. Most have lost most of the original (desirable) qualities e.g taste;
Poor/undesirable qualities are perpetuated through subsequent generations;
Products’ qualities are irreversible- can’t get original species/qualities;

Comments

Explain the physiological process responsible for keeping young seedlings upright.

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN15

Explain the physiological process responsible for keeping young seedlings upright.

answers

Osmosis; water moves into the cells becoming turgid; attaining mechanical support ;

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN14

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN14

The photograph below illustrates a germinating seedling.

(a) Name the type of germination illustrated in the photograph.
(b) Explain the function of each of the parts labelled G and H.
G
H

answers

a. Epigeal;
b. G- Elongates to expose the foliage leaves to light photosynthesis
H- Stores food (for growth);
For photosynthesis (it is green);
Protects plumule during germination;

Comments

Name the causative agent for Tuberculosis

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN13

Name the causative agent for Tuberculosis

answers

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN12

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN12

Explain the survival values of the following tropic responses to plants.
(a) Geotropism
(b) Phototropism

answers

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN11

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN11

The set up below illustrates a certain physiological process.

(a) (i) Name the physiological process.
(ii) Give two examples of the process named in (a) (i) above in plants.
(b) State two ways by which the movement of dye molecules in the set up would be slowed down.

answers

a i) Diffusion;
ii) Gaseous exchange/excretion of carbon (IV) oxide and oxygen;
Translocation of materials;
Absorption/uptake of mineral ions/salts;
b. Lowering the temperature of the medium;
Increasing thickness of the membrane;
Use less dye/add more water/reducing the concentration gradient;

Comments

State two structural adaptations of leaves that maximize efficiency in gaseous exchange

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN10

State two structural adaptations of leaves that maximize efficiency in gaseous exchange

answers

Comments

State the effect of movement of the diaphragm muscles during inhalation in mammals.

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN10

State the effect of movement of the diaphragm muscles during inhalation in mammals.

answers

The diaphragm contracts and flattens; leading to increase in volume of the thoracic cavity; decreasing the pressure inside it (forcing in the air);

Comments

Give one reason why the coarse adjustment knob should not be used to lower the high power objective.

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN09

Give one reason why the coarse adjustment knob should not be used to lower the high power objective.

answers

Can break the objective lens/cover slip/slide;
Can destroy the specimen (making the microscope dirty);

Comments

State the function of a mirror in a light microscope.

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN09

State the function of a mirror in a light microscope.

answers

Reflects light (through the condenser) to the object;

Comments

<<Previous

Forward>>

K.C.S.E Biology Q & A - MODEL 2017PP1QN21

K.C.S.E Biology Q & A - MODEL 2017PP1QN21

State three methods of fossil formation.

State three methods of fossil formation.

K.C.S.E Biology Q & A - MODEL 2017PP1QN19

K.C.S.E Biology Q & A - MODEL 2017PP1QN19

K.C.S.E Biology Q & A - MODEL 2017PP1QN18

K.C.S.E Biology Q & A - MODEL 2017PP1QN18

How is the surface area increased in the mammalian small intestines?

How is the surface area increased in the mammalian small intestines?

K.C.S.E Biology Q & A - MODEL 2017PP1QN16

K.C.S.E Biology Q & A - MODEL 2017PP1QN16

Explain the physiological process responsible for keeping young seedlings upright.

Explain the physiological process responsible for keeping young seedlings upright.

K.C.S.E Biology Q & A - MODEL 2017PP1QN14

K.C.S.E Biology Q & A - MODEL 2017PP1QN14

Name the causative agent for Tuberculosis

Name the causative agent for Tuberculosis

K.C.S.E Biology Q & A - MODEL 2017PP1QN12

K.C.S.E Biology Q & A - MODEL 2017PP1QN12

K.C.S.E Biology Q & A - MODEL 2017PP1QN11

K.C.S.E Biology Q & A - MODEL 2017PP1QN11

State two structural adaptations of leaves that maximize efficiency in gaseous exchange

State two structural adaptations of leaves that maximize efficiency in gaseous exchange

State the effect of movement of the diaphragm muscles during inhalation in mammals.

State the effect of movement of the diaphragm muscles during inhalation in mammals.

Give one reason why the coarse adjustment knob should not be used to lower the high power objective.

Give one reason why the coarse adjustment knob should not be used to lower the high power objective.

State the function of a mirror in a light microscope.

State the function of a mirror in a light microscope.

TOPICS

Form 2

Form 3

Form 4

Archives

Categories