Tag: the respiratory system

Questions Related to the respiratory system

Choose the correct answers from the alternatives given :
Which metabolic pathway is common to both the aerobic and anaerobic catabolism of sugar?

parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. Synthesis of acetyl CoA from pyruvic acid

  2. Glycolysis

  3. Krebs cycle

  4. Electron transport chain

Show answer
Correct Option: B
Explanation:

  • First part for both type of respiration aerobic and anaerobic is glycolysis where the sugar is broken down to pyruvic acid.
  • Glycolysis takes place in the cytoplasm of the cells and does not require for the presnece of any organelles.
  • So both kind of organisms are able to perform glycolysis whether they perform aerobic or anaerobic reactions.
  • Thus it can be said that in both kind of respiration glycolysis is a common process which provides substrate for further reactions in both kind of respiration. Pyruvic acid which converts to acetyl coA and takes part in kerb cycle while pyruvic acid converts to lactic acid or alcohol in fermentation reaction.
  • Therefore the correct answer is option 'Glycolysis'.










Choose the correct answers from the alternatives given :
Glycolysis starts and ends m the 

parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. cytoplasm

  2. plasma membrane

  3. nucleus

  4. mitochondrion

Show answer
Correct Option: A
Explanation:
  • The whole process of glycolysis takes place in the cytoplasm it does not require any membrane bound organelles to perform the reaction.
  • GLycolysis is the main process to obtain energy in the prokaryotic organisms where there are no membrane bound organelles present and glycolysis is the only source of obatining energy.
  • Therefore the enzymes and substrate required for the process of glycolysis are present in the cytoplasm and the whole reaction takes place in the cytoplasm.
  • Therefore the answer 'cytoplasm' is correct.

Choose the correct answers from the alternatives given :
Select the true statement

parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. glycolysis produces equal numbers of ATP molecules regardless of the presence or absence of oxygen

  2. more ATP molecules are produced per molecule of glucose when glycolysis occurs in aerobic conditions

  3. more ATP molecules are produced per molecule of glucose wvhen glycolysis occurs in anaerobic conditions

  4. none of the above are true

Show answer
Correct Option: A
Explanation:


  • As the reaction of glycolysis takes place in the cytoplasm of cell where it can proceed in the absence of oxygen molecule. 
  • It does not require the presence of oxygen of to proceed further.
  • It will produce 4 ATP molecules and use 2 molecules of ATP, which gives the cell the net gain of 2 ATP at the end of the glycolysis process.
  • Presence of oxygen or absence of oxygen does not hinder the process of glycolysis and prodution of ATP by glycolysis.
  • Therefore the answere option 'glycolysis produces equal numbers of ATP molecules regardless of the presence or absence of oxygen' is true.

State whether the following statements are true or false.
Glycolysis and fermentation are thought to be older processes than the electron transport system and the Krebs cycle 

parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

The initial processes for energy generation by prokaryotes included anaerobic processes such as Glycolysis and Fermentation. The latter happening of endosymbiosis was the major revolution in bringing up aerobic respiration with the advent of mitochondria within the cells.

Before that, the energy generation was an anaerobic process without using oxygen in Glycolysis and Fermentation.
So, the correct option is 'True'.

State whether the following statements are true or false.
The most efficient pathway for ATP production in animal cells is by glycolysis.

parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. True

  2. False

Show answer
Correct Option: B
Explanation:
  • Glycolysis is the pathway were one molecule of glucose is broken down to 2 molecules of pyruvate by the phosphorylation and dephosphorylation reactions.
  • 2 molecules of ATP are used in phosphorylation reaction of glycolysis. First while conversion of glucose to glucose-6-phosphate and the second one during conversion of fructose to fructose1,6-biphosphate.
  • While 4 ATP molecules are produced in the dephosphorylation reaction. 2 ATP are produced while conversion of  1,3 bisphosphoglyceric acid to 3-phosphoglyceric acid and another 2 ATP during conversion of phosphophenolepyruvate to pyruvic acid.
  • So the net gain of ATP at the end of one glycolysis reaction is 2. SO glycolysis is not a efficient pathway for the production of ATP in animal cells, in turn it is a part of the chain of reaction which take place before aerobic or anaerobic respiration in animal cells.
  • Glycolysis provided the reaction of aerobic and anaerobic respiration with the substrates to carry the reaction further and produce ATPs in mitochondria where the prominent reactions for production of energy in animal cell takes place.
  • Glycolysis takes place in the cytoplasm of the cell and the product of the glycolysis is transported to the mitochondria.
  • Therefore Glycolysis is not the most efficient pathway for ATP production. So the sentence above is FALSE and therefore the option 'False' is correct.

Choose the correct answers from the alternatives given :
Which of the following does not form during glycolysis?

parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. NADH

  2. ATP

  3. Pyruvate

  4. $FADH _2$

Show answer
Correct Option: D
Explanation:
  • NADH is formed in the glycolysis after the reaction of conversion Glyceradehyde 3 phosphate to 3 phosphoglyeric acid when electrons re released and are accepted by the NAD.
  • ATP is formed  while conversion of 1,3 bisphosphoglyceric acid to phospoglyceric acid and also while conversion of phosphophenol to pyruvic acid.
  • And pyruvate is the end product of the glycolysis.
  • FADH is the product which is formed  during the the kerb cycle while formation of succunic acid to malic acid.
  • Thereofte the correct answer is '$FADH _2$'
During complete metabolism of glucose, the number of ATP formed is
parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. 2

  2. 12

  3. 36

  4. 44

Show answer
Correct Option: C
Explanation:
There is a gain of $2$ ATP molecules during glycolysis and $2$ ATP(GTP) molecules during double Krebs cycle. A total of $10$ ${NADH} _{2}$ molecules are formed in aerobic respiration. Thus, the net gain from complete oxidation of a molecule of glucose in muscle and nerve cells is 36 ATP molecules ($10$ ${NADH} _{2}=30 ATP, 2{FADH} _{2}=4 ATP$, four formed by substrate-level phosphorylation in glycolysis and Krebs' cycle and two consumed in transport of the ${NADH} _{2}$ molecules into mitochondria). In aerobic prokaryotes, heart, liver and kidneys, $38$ ATP molecules are produced per glucose molecule oxidised. passage of ATP molecules from inside of mitochondria to the cytoplasm is through facilitated diffusion.
Thus, there is a net gain of $36$ or $38$ ATP molecules depending upon the type of aerobic respiration.
[Note: $1{NADH} _{2}=3ATP$ and $1{FADH} _{2}=2ATP$].
So the correct answer is '36'.
Which of the following statements regarding metabolic pathways is incorrect?
parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. Many of the steps of glycolysis can run in reverse

  2. Starch, sucrose or glycogen must be hydrolysed before it can enter the glycolysis.

  3. After fats are digested, glycerol enters glycolysis by forming DHAP.

  4. After fat digestion, fatty acids can no longer participate in cellular respiration.

Show answer
Correct Option: D
Explanation:

After fats are digested into fatty acids and glycerol, the following products can take place in cellular respiration.

So, the correct option is 'After fat digestion, fatty acids can no longer participate in cellular respiration.'.

The balance sheet for ATP production in glycolysis has been given below. Select the option which correctly fills up the blanks for P,Q,R and S. ['X' stands for 'nil'].

Steps ATP Utilisation ATP Production
1. $Glucose\rightarrow Glucose-6-phosphate$ P X
2. $Fructose-6-phosphate\rightarrow Fructose-1, 6-bisphosphate$ 1 Q
3. $1,3-bisphosphoglyceric acid\rightarrow 3-Phospho-glyceric acid$ X R
4. $2-Phosphoenol pyruvic acid\rightarrow Pyruvic acid$ S 2
parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. P-1; Q-X; R-X; S-2

  2. P-1; Q-X; R-2; S-X

  3. P-2; Q-1; R-X; S-1

  4. P-X; Q-1; R-2; S-X

Show answer
Correct Option: B
Explanation:
During glycolysis, the conversion of glucose into glucose-6-phosphate requires the utilization of one ATP molecule and no ATP molecules are produced. Similarly, there is no production of ATP molecules during the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate and only one ATP molecule is utilized. Also, during the conversion of 1,3−bisphosphoglycericacid to 3−Phospho−glycericacid and that of 2−Phosphoenolpyruvicacid to pyruvic acid, tow molecules each of ATP as utilized and no ATP is produced.

So, the correct answer is 'P-1; Q-X; R-2; S-X'.
Which of the following conversions involve ATP synthesis during glycolysis?
parts of respiration cellular respiration the respiratory system breathing for energy biology types of respiration

  1. Glucose$\rightarrow$Glucose-6-phosphate

  2. Fructose-6-phosphate$\rightarrow$Fructose-1,6-biphosphate

  3. 1,3-bisphosphoglyceric acid (BPGA) $\rightarrow$ 3-phosphoglyceric acid (PGA)

  4. All of these

Show answer
Correct Option: C
Explanation:

In the energy conserving phase of glycolysis, the conversion of BPGA to PGA is catalyzed by phosphoglycerate kinase. The phosphate on carbon 1 is transferred to a molecule of ADP, yielding ATP and 3-phosphoglycerate. This type of ATP synthesis, traditionally referred to as substrate-level phosphorylation, involves the direct transfer of a phosphate group from a substrate molecule to ADP, to form ATP.
$1,3-bisphosphoglycerate+ADP\overset{Phosphoglycerate kinase}{\underset{{Mg}^{2+}}{\rightleftharpoons}}3-phosphoglycerate+ATP$