CHAPTER 3 EXCRETIONSUBJECTIVE QUESTIONS3.1 Human Excretion

1 Complete the table below by stating the method of excretion and excretory materials for the following excretory organ.

Excretory organ Method of excretion Excretory materials(a) Skin(b) Lungs(c) Kidneys

2 Fill in the blanks with the words given.

(a) The process of removing waste products, produced during chemical processes in the cells, is called ___________________.

(b) If wastes are not removed, _____________ substances build up and these can damage organs in the body.

(c) The excretory products of humans are _____________ , carbon dioxide, urea and mineral salts.

(d) The excretory organs of humans are lungs, _________and the kidneys.

3.2 The Urinary System in Humans

3 Tick the statements below that are true.(a) The kidneys are located at the back of the body and

form the main organs of the urinary system. (b) The function of the kidney is to remove water and

carbon dioxide.

skin toxic water excretion

(c) The kidneys are bean-shaped and roughly the size of a fist.

4 Name the parts of the human urinary system based on the following functions.

Parts of urinarysystem in human

Function

(a) Tube that carries urine from the kidney to the bladder

(b) Excretory organ that removes wastes like urea,water and mineral salts from the blood into the urine

(c) Tube that carries urine from the bladder for removal

(d) Temporary storage for the urine before removal

5 Label the human kidney using the words given.

Cortex Ureter Medulla Vein Pelvis of kidneyArtery

3.3 Excretion in Plants6 Underline the correct word in the brackets so that each

sentence becomes a true statement.(a) Plants excrete water, [urea, mineral salts], oxygen,

carbon dioxide and other nitrogenous wastes.(b) Plants excrete their waste products by simple diffusion

through the cell [wall, membrane] and through the stomata.

OBJECTIVE QUESTIONS3.1 Human Excretion

1 Which of the following excretory products are excreted through the lungs?

A Water and ureaB Water and mineral saltsC Carbon dioxide and saltsD Carbon dioxide and water

2 All the following are excretory organs exceptA skin C lungsB heart D kidneys

3.2 The Urinary System in Humans

3 Which of the following is not a function of the kidneys?A It removes urea from the bodyB It controls the pH of the bloodC It removes excess sugar in the bloodD It regulates the amount of water and mineral salts in the

body

4 Diagram 1 shows the cross section of the human kidney.

Which part marked P, Q, R and S carries urine from the kidney to the urinary bladder?A P C RB Q D S

5 Which of the following are not true?

Excretory product Excretory organA Water KidneysB Mineral salts SkinC Urea LungsD Carbon dioxide Lungs

3.3 Excretion in Plants6 Which of the following excretory products from plants can be

used to relieve pain?A Latex C ResinB Tannin D Caffeine

7 Which of the following plants produce latex?A Soya C Rubber treeB Coconut tree D Sunflower plant

REVISION

1 Which of these are excretory organs?

I

II

III

A I an II only C II and III only

B I and III only D I, II and III

2 Which of the following excretory product does not match?

Excretory organs Excretory productA Kidney Mineral saltsB Lungs WaterC Skin UreaD Skin Carbon dioxide

3 Diagram 1 shows the human urinary system.

(a) Name the parts labelled J, K and L.J : _______________________________

K : _______________________________L : _______________________________

(b) State the function of the kidneys. __________________________________________

(c) Describe what happens to the body when both kidneys fail.

__________________________________________ __________________________________________

(d) State how kidney failure can be treated. __________________________________________ __________________________________________

4 The following information describes the excretion of plants.

(a) State three excretory products of plants that are harmful to humans.

___________________________________________

Some of the excretory products in plants are useful to humans while others are poisonous.to human while others are poisonous.

___________________________________________(b) Name the parts of plants that will eliminate the

following excretory products. (i) Latex

_______________________________________ (ii) Quinine

________________________________________