KNEC KCSE BIOLOGY TOPICAL QUESTIONS

State three homeostatic roles of the liver.

2/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN23

State three homeostatic roles of the liver.

answers

Thermoregulation;
Blood sugar regulation
Protein/amino acid/fat regulation

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN12

2/7/2020

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K.C.S.E Biology Q & A - MODEL 2019PP1QN12

While investigating a certain metabolic process in plants, students set up the apparatus as shown be low in a classroom and monitored it for 48 hours.

(a) Identify the metabolic process under investigation.
(b) Account for the observations made in the test tube at the end of the investigation.

answers

Comments

Explain why significantly increasing the blood pH slows down the rate of selective reabsorption of materials in the kidney tubules.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2019PP1QN05

Explain why significantly increasing the blood pH slows down the rate of selective reabsorption of materials in the kidney tubules.

answers

selective reabsorption of materials in the kidney tubules is energy dependent/require energy ; synthesized through the process of (cellular) respiration/action of respiratory enzymes; whose working (effectiveness)is affected by change in pH/are denatured at high pH; pH affects the working / permeability of the (kidney tubule cells)membrane;

Comments

K.C.S.E Biology Q & A - MODEL 2018PP2QN01

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP2QN01

The diagram below illustrates a section of the mammalian kidney.

(a) Name the structures labelled E and F.
E
F
(b) Explain the processes that take place in the regions labelled G and H.
Region G
Region H

answers

 (a) E—Glomerulus;
F — Interlobular artery/branch of renal artery;
(b) Region G
At the (glomerulus), the afferent arteriole which brings blood to the glomerulus is wider than the efferent arteriole; this creates high pressure; leading to ultrafiltration; At the proximal convoluted tubule /distal convoluted tubule, substances required by the body/amino acid substances required by the body (amino acids/glucose/vitamins! some water; are selectively re-absorbed (into the blood stream); hence selective reabsorption;
Region H
At the descending arm of/limb of the Loop of Henle, water is selectively reabsorbed; At the ascending arm/limb of the Loop of Henle, sodium ions/salts are actively/selectively reabsorbed; At the collecting duct, water is (selectively) reabsorbed:

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vvK.C.S.E Biology Q & A - MODEL 2018PP1QN27

1/7/2020

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K.C.S.E Biology Q & A - MODEL 2018PP1QN27

Below is a graphical representation of how basal metabolic rates compare in Various animals.

From the graph, explain why the mouse has a higher breathing rate than the elephant.

answers

Mouse is active/has a large surface area to volume ratio; hence has a higher metabolic rate (rate of breathing) to cope with the rate at which energy (oxygen) is consumed or lost to the environment; an elephant is less active/has a small surface area to volume ratio hence has a lower rate at which energy (oxygen) is used or lost; or
Mouse is small in size/has large surface area to volume ratio; hence has a metabolic rate (rate of breathing) to cope with the rate at which oxygen is consumed/energy ¡s lost to the environment; an elephant is large in size/has small surface area to volume ratio; hence has a lower rate at which oxygen/energy is lost;

Comments

State two advantages terrestrial animals have in excreting urea as their main nitrogenous waste product.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP1QN26

State two advantages terrestrial animals have in excreting urea as their main nitrogenous waste product.

answers

Less-toxic;
Very soluble;
A small molecule (easily filtered in the kidneys);
Requires less water to excrete;

Comments

Explain why a camel has a longer nephron than a whale.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP1QN24

Explain why a camel has a longer nephron than a whale.

answers

A camel is a desert animal, a longer nephron increases the surface area for reabsorption of water; to conserve it; a whale is aquatic animal (codes not need to conserve water)

Comments

Name three structures of the skin essential for its homeostatic function.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP1QN11

Name three structures of the skin essential for its homeostatic function.

ANSWERS

Blood vessels/arterioles;
Hair;
Sweat glands;
Erector pill muscles;
Nerve endings

Comments

State one homeostatic role of the human skin.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP1QN11

State one homeostatic role of the human skin.

ANSWERS

Thermoregulation;
Osmoregulation;
Regulating salt balance;

Comments

State why it is important for plants to lose water to the atmosphere.

1/7/2020

Comments

K.C.S.E Biology Q & A - MODEL 2018PP1QN05

State why it is important for plants to lose water to the atmosphere.

answers

Cools the plant;
For uptake of water up the xylem vessels;
Mechanism through which mineral elements are transported in the plant; ‘
Removal excess water;
Maintains turgor, pressure;

Comments

State two ways by which plants manage their solid wastes.

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2017PP1QN22

State two ways by which plants manage their solid wastes.

answers

Storage in tissues in non-toxic forms;
Deposited in plant tissues/organs- which age and fall off; (e.g leaves, bark, fruits, flowers)

Comments

Name one salivary gland in humans.

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2016PP1QN23

Name one salivary gland in humans.

answers

Sublingual; submaxillary/ submandibular; parotid

Comments

K.C.S.E Biology Q & A - MODEL 2016PP1QN016

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2016PP1QN016

State one use of each of the following excretory products of plants:
(a) colchicine
(b) papain

answers

(a) colchicine
Inducing polyploidy/ treatment
(b) papain
Meat tenderizer

Comments

Why are plants able to accumulate most of their waste products for long?

30/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2016PP1QN02

Why are plants able to accumulate most of their waste products for long?

answers

Most of the waste products are harmless;
Waste products are converted into harmless products;

Comments

Describe the role of the human skin in homeostasis.

28/6/2020

Comments

K.C.S.E Biology Q & A - MODEL 2014PP2QN08

Describe the role of the human skin in homeostasis.

answers

When body temperature is lowered below normal; arterioles in the skin constrict; blood is diverted to a shunt system; less blood flows to the skin/less heat is lost; when body temperature is raised above normal;arterioles in the skin dilate;more blood flows to the skin; more heat is lost by convection and radiation;when body temperature is lowered below normal:erector-pilli muscle s contract, hair stands erect; more air is trapped, air is a bad conductor;and insulates the body against heat loss; when body temperature is raised above normal: erectorpi11i muscles relax, hair lies on skin;less air is trapped, more heat is lost; when body temperature is lowered below normal: less fluids are absorbed by sweat glands;less sweating, less vaporisation of water;
when body temperature is raised above normal:sweat glands are more stimulated and more sweat is produced; water in sweat evaporates and takes up heat from the body;body is cooled/body temperature is lowered;

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<<Previous

State three homeostatic roles of the liver.

State three homeostatic roles of the liver.

K.C.S.E Biology Q & A - MODEL 2019PP1QN12

K.C.S.E Biology Q & A - MODEL 2019PP1QN12

Explain why significantly increasing the blood pH slows down the rate of selective reabsorption of materials in the kidney tubules.

Explain why significantly increasing the blood pH slows down the rate of selective reabsorption of materials in the kidney tubules.

K.C.S.E Biology Q & A - MODEL 2018PP2QN01

K.C.S.E Biology Q & A - MODEL 2018PP2QN01

vvK.C.S.E Biology Q & A - MODEL 2018PP1QN27

K.C.S.E Biology Q & A - MODEL 2018PP1QN27

State two advantages terrestrial animals have in excreting urea as their main nitrogenous waste product.

State two advantages terrestrial animals have in excreting urea as their main nitrogenous waste product.

Explain why a camel has a longer nephron than a whale.

Explain why a camel has a longer nephron than a whale.

Name three structures of the skin essential for its homeostatic function.

Name three structures of the skin essential for its homeostatic function.

State one homeostatic role of the human skin.

State one homeostatic role of the human skin.

State why it is important for plants to lose water to the atmosphere.

State why it is important for plants to lose water to the atmosphere.

State two ways by which plants manage their solid wastes.

State two ways by which plants manage their solid wastes.

Name one salivary gland in humans.

Name one salivary gland in humans.

K.C.S.E Biology Q & A - MODEL 2016PP1QN016

K.C.S.E Biology Q & A - MODEL 2016PP1QN016

Why are plants able to accumulate most of their waste products for long?

Why are plants able to accumulate most of their waste products for long?

Describe the role of the human skin in homeostasis.

Describe the role of the human skin in homeostasis.

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