Botany Problems on “Respiratory Quotient”.
1. Is it possible to make calculations of the net gain of ATP?
a) Not possible
b) Possible only theoretically
c) Possible only in reality
d) Sometimes possible and sometimes not
Answer: b
Clarification: Yes, it is possible to make calculations of the net gain of the ATP that is formed in the respiratory pathway by the oxidation of some suitable respiratory substrates but this can remain only a theoretical exercise as the real amount of energy released in the cell may vary.
2. Which of the following is an assumption of the respiratory balance sheet?
a) Respiration is a sequential pathway
b) Respiration does not exist
c) Energy cannot be calculated in a respiratory pathway
d) Energy is always lost in the form of heat in respiration
Answer: a
Clarification: One of the assumptions made in the respiratory balance sheet is that there is a sequential, orderly pathway functioning, with one substrate forming the next and with glycolysis, TCA cycle and ETS pathway following one after another.
3. Which of the following is not an assumption of the respiratory balance sheet?
a) NADH synthesised in glycolysis is transferred into mitochondria
b) None of the intermediates is used to synthesise other compounds
c) Respiration is a sequential pathway
d) Energy can never be stored
Answer: d
Clarification: Certain assumptions of the respiratory balance sheet include that none of the intermediates in the pathway are utilised to synthesise any other compound. Respiration is a sequential pathway and NADH synthesised in glycolysis is transferred into the mitochondria and undergoes oxidative phosphorylation.
4. All carbohydrates except for glucose can be respired in a respiratory pathway.
a) True
b) False
Answer: b
Clarification: In a respiratory pathway, only glucose is being respired, no other alternative substrates are entering in the pathway at any of the intermediary stages.
5. Do all the respiratory pathways work simultaneously?
a) No, not at all
b) They take place one after the other
c) Yes, they work simultaneously
d) Sometimes they work independently
Answer: c
Clarification: The assumptions made in the respiratory balance sheet are not valid for the living system. All pathways work simultaneously and do not take place one after another.
6. When is the ATP utilised?
a) It is utilised as and when needed
b) It is never utilised
c) It is only in the stored form
d) Only when the cell is about to replicate
Answer: a
Clarification: ATP is utilised as and when needed. Substrates enter the pathway and are withdrawn from it as and when necessary. Enzymatic rates in these pathways are controlled by multiple means.
7. How many ATP molecules are gained during aerobic respiration?
a) 2 ATP
b) 10 ATP
c) 35 ATP
d) 38 ATP
Answer: d
Clarification: Aerobic respiration involves the complete oxidation of glucose. There can be a net gain of 38 ATP molecules during aerobic respiration of one molecule of glucose.
8. How many ATP molecules are gained during fermentation?
a) 8 ATP
b) 2 ATP
c) 10 ATP
d) 4 ATP
Answer: b
Clarification: In fermentation, there is a net gain of only two molecules of ATP for each molecule of glucose degraded to pyruvic acid whereas many more molecules of ATP are generated under aerobic conditions.
9. What is the speed of oxidation of NADH in case of fermentation?
a) Vigorous
b) Very slow
c) Slow
d) Fast
Answer: c
Clarification: NADH is oxidised to NAD+ rather slowly in fermentation, however, the reaction is very vigorous in the case of aerobic respiration. The reducing agent in fermentation is NADH + H+.
10. Fermentation accounts for the complete breakdown of glucose and sucrose.
a) True
b) False
Answer: b
Clarification: Fermentation accounts for only a partial breakdown of glucose whereas in aerobic respiration it is completely degraded to CO2 and H2O.
11. What is the full form of RQ?
a) Respiratory Quotient
b) Reservatory Quotient
c) Reservation Q-value
d) Reservatory Q-value
Answer: a
Clarification: RQ stands for Respiratory Quotient. It is the ratio of the volume of CO2 evolved to the volume of O2 consumed in respiration. It is also known as the respiratory ratio.
12. On which of the following does the respiratory quotient depend?
a) The respiratory concentration of Oxygen
b) The respiratory substrate used during respiration
c) The volume of Carbon-dioxide evolved
d) Energy evolved during respiration
Answer: b
Clarification: The respiratory quotient depends upon the type of respiratory substrate used during respiration. In living organisms, respiratory substrates are often more than one.
13. What is the value of RQ in carbohydrates?
a) 0.7
b) 0.3
c) 1
d) 10
Answer: c
Clarification: When carbohydrates are used as substrates and are completely oxidised, the RQ will be 1, because equal amounts of CO2 and O2 are evolved and consumed respectively.
14. What is the RQ value for tripalmitin?
a) 0.9
b) 1
c) 0.3
d) 0.7
Answer: d
Clarification: When fats are used in respiration, the RQ is less than 1. For a fatty acid, tripalmitin, the ratio of the volume of carbon dioxide evolved to the volume of oxygen evolved is 0.7.
15. What is the respiratory quotient for organic acids?
a) More than 1
b) Less than zero
c) Zero
d) Less than one but greater than Zero
Answer: a
Clarification: Organic acids have R.Q value more than one. But when proteins are respiratory substrates the ratio would be about 0.9. Pure proteins or fats are never used as respiratory substrates.
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