Past Questions and Answers on Respiration in Mammals



1.      Which of the following is not true about respiration?

A.    Oxygen combines with haemoglobin at respiratory surface
B.     Respiration can take place in the absence of oxygen
C.     Carbon dioxide produced in the tissues is removed by the process of osmosis
D.    Respiratory gases are transported in solution in the higher animals

2.      In the absence of oxygen, the pyruvic acid produced during glycolysis is converted to CO2 and
A. water                   
B. glycerol          
C. ethanol           
D. citric acid

3.      The end product of glycolysis in plants and animals is
A. pyruvic acid            
B. citric acid            
C. aspartic acid        
D. malic acid

4.      Anaerobic respiration differs from aerobic respiration by the production of
A. less amount of energy and water
B. greater amount of energy and alcohol
C. less amount of energy and alcohol
D. greater amount of energy and water

5.      Which of following movements occur during exhalation?
A. The diaphragm and intercostal muscles relax
B. The thoracic cavity increases in volume
C. The diaphragm and intercostal muscles contract
D. The diaphragm contracts and the intercostal muscle relax

6.    The gas produced during tissue respiration can be identified by using
A. calcium hydroxide
B. copper sulphate
C. calcium carbonate
D. sodium hydroxide

7.    When yeast respire anaerobically, it converts simple sugar to carbon (IV) oxide and
A. oxygen                 
B. acid           
C. alcohol           
D. water

8.    Tissue respiration is important for the
A. absorption of oxygen into the alveoli
B. release of carbon (IV) oxide into the lungs
C. release of energy for the body use
D. exhalation of carbon(IV) oxide from the lungs

9.    The surface of an alveolus in mammal is well supplied with tiny blood vessels known as
A. arterioles             
B. venules     
C. arteries           
D. capillaries

10.    The anaerobic fermentation of a glucose molecule yields
A. 38 ATP molecules
B. 2 ATP molecules and alcohol
C. pyruvic acid and alcohol
D. water and carbon (IV) oxide

11.    The mammalian lung is made airtight by the
A. pleural cavity    
B. mucous membrane     
C. pleural membrane    
D. diaphragm

12.    A test tube containing yeast in glucose solution containing alkaline pyrogallol. The bubbles of carbon (IV) oxide produced indicates that the yeast cells are
A. respiring in the absence of oxygen
B. liberating oxygen on their own
C. living and consuming oxygen
D. being killed by the alcohol produced

13.    An increase in air pressure in the lungs is due to the
A. increase in the volume of the thoracic cavity
B. upward movement of the ribs
C. relaxation of the diaphragm
D. contraction of the intercostal muscles

14.    The formation of water in the tissue respiration results from the
A. breakdown of water molecules
B. reduction of oxygen by hydrogen
C. reduction of carbon(IV) oxide
D. combination of water molecules

15.    Exhaled air differs from inhaled air in that it
A. less amount of carbon (IV) oxide
B. is usually lower in temperature
C. often has more oxygen
D. usually has more water vapour

16.    The enzymes of the glycolytic pathway are located in the?
A. mitochondria            
B. gastric juice        
C. plasma        
D. cytoplasm

17.    Respiration is essential to life since
A. oxygen is used up
B. water is released into the atmosphere
C. a lot of glucose is used up
D. energy is released

18.    The process of anaerobic respiration of yeast in sugar solution is known as
A. oxidation            
B. fermentation  
C. tissue respiration    
D. alcohol production

19.    The upper part of the trachea in mammals is called
A. palate                   
B. epiglottis         
C. larynx         
D. glottis

20.    Anaerobic respiration can be employed in industry for
A. brewing                   
B. gas welding      
C. making beads       
D. manufacturing


1. C

6. C

11. C

16. A

2. C

7. C

12. A

17. D

3. A

8. C

13. A

18. B

4. C

9. D

14. B

19. C

5. D

10. C

15. D

20. A


1. (SSCE, 1994) (a) What is external respiration?

(b) Distinguish between aerobic respiration and anaerobic respiration.

(c)   State three characteristics of respiratory surfaces in mammals. 


(i) External respiration: is the uptake of oxygen and simultaneous elimination of carbon dioxide and water. This is commonly referred to as breathing.

(ii) Refer to blog content

(iii) Characteristics features of respiratory surface in mammals 

1. presence of thin epithelial lininga Large surface to volume ratio

3.  the surfaces are moist

4. presence of large number of blood vessels in them (highly vascularized)

2.      (SSCE, 2000 Q3) (a) Distinguish between tissue respiration and gaseous exchange.

(b) (i) What are the main stages in glycolysis?

(ii) What is the importance of Kreb’s cycle?(

iii) Explain briefly the role of anaerobic respiration in two industries.


(i) Tissue respiration: is a series of chemical reactions within the cell in which organic molecules are oxidized to release energy.   Gaseous exchange: is the uptake of oxygen and simultaneous elimination of carbon dioxide and water vapour. This is commonly referred to as breathing.

(b) (i) Main stages in Glycolysis

1.  Phosphorylation of glucose by enzymes called hexokinases to form glucose- 6-phosphate

2. Glucose-phosphate rearranged into fructose 6-phosphate.

3. ATP is used in conversion of fructose-phosphate to fructose 1, 6-disphosphate

4. Fructose -disphosphate molecule split into two 3C triose phosphate molecule. 

5. Hydrogen atoms are removed from the triose phosphate. 

6. Two phosphates molecules are lost and two molecules of ATP are formed. 

(ii) Importance of Kreb’s cycle

It is valuable source of intermediates used to manufacture other substances like amino acids and fatty acids. It provides hydrogen atoms which ultimately yield the major parts of the energy.

(iii) Role of anaerobic respiration

1. Yoghurt: The bacteria used in making yoghurt are Lactobacillus bacteria. The bacteria break down milk sugar (lactose) into lactic acid. The lactic acid lowers the pH of the yoghurt, which helps to preserve it.

2. Baking: In production of bread, added yeast feeds on the sugars present in the bread dough and produces the gas carbon dioxide. The carbon dioxide causes the dough to rise.

3. Brewing: It involves breaking the starch in the grains (malted barley and malted wheat) by yeasts into alcohol and carbon dioxide.  

4. Kenkey: microorganism in corn dough respire anaerobically to produce alcohol which gives taste to the kenkey.  

3.      (SSCE, 2003 Q1) (a) Describe each of the following processes in tissue respiration in living cells:

(i) glycolysis       

(ii) the kreb’s cycle

(b) State four difference between aerobic respiration and anaerobic respiration.


(a) (i) Refer to blog content

(ii) Kreb’s cycle

This results in the completion of pyruvate to CO2 and water, with the release of a large amount of energy. Pyruvate (3C) has one carbon atom removed and the acetyl group (2C) formed then combines with Co-enzyme A to form acetyl-Co-enzyme A which enters a series of cyclic reactions.

Acetyl Co A combines with oxaloacetate (4C) to from citrate (6C) which is oxidized and decarboxylated to form succinate (4C). 

The succinate is converted to oxaloacetate through molecular rearrangement and combines with acetyl Co A reform citrate.


(b) Refer to blog content

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