Tag: respiration

Questions Related to respiration

Oxidation of glucose to CO$ _2$ and water occurs during

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Glycolysis

  2. Pentose phosphate pathway

  3. Krebs cycle

  4. All of the above

Show answer
Correct Option: B
Explanation:

Pentose phosphate pathway is the only pathway in which glucose is completely oxidised to CO$ _2$ and H$ _2$O. It is also called HMP (hexose monophosphate shunt) as it is an alternate pathway to glycolysis. The primary substrate glucose is first phosphorylated to glucose-6-phosphate in presence of G6PD by consuming 1 ATP. A net gain of 35 ATP is achieved by oxidation of 1 molecule of glucose.

So the answer is 'Pentose phosphate pathway'.

Which of the following enzyme helps in conversion of 6-phosphogluconate to ribulose-5-phosphate?

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. 6-phosphogluconate dehydrogenase

  2. Hexokinase

  3. Alpha-ketoglutarate

  4. None of the above

Show answer
Correct Option: A
Explanation:

This conversion takes place during the oxidative phase of the pentose phosphate pathway.

Here, When 6-phosphogluconate converts to ribose 5-phosphate, the enzyme used is 6-phosphogluconate dehydrogenase. 
In this step an NADP⁺ converts to NADPH and CO₂ is released.
So, the correct option is '6-phosphogluconate dehydrogenase.'

 Erythrose 4-phosphate is used in synthesis of 

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Carbohydrates.

  2. Aromatic amino acid.

  3. NADH.

  4. Erythrose-4-phosphate.

Show answer
Correct Option: B
Explanation:

Erythrose-4-phosphate is an intermediate produced in the pentose phosphate pathway.  It is involved in the biosynthesis of aromatic amino acids. All the carbons in phenylalanine and tyrosine are produced from erythrose-4-phosphate and phosphoenolpyruvate. Phenylalanine and tyrosine are aromatic amino acids. Thus the correct answer is option B.

Which of the following cellular metabolic processes can occur both in the presence or absence of ${O} _{2}$?
hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Glycolysis

  2. Fermentation

  3. TCA cycle

  4. Electron transport coupled with chemiosmosis

Show answer
Correct Option: A
Explanation:

Glycolysis is an oxidative process in which one molecule of glucose is partially oxidised into two molecules of pyruvate in a series of enzyme catalysed reactions. Glycolysis, the major pathway for glucose metabolism, occurs in the cytosol of cells. It is a unique pathway that occurs aerobically as well as anaerobically and does not involve molecular oxygen.

Which one requires oxygen?

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Fermentation.

  2. EMP pathway.

  3. Pentose phosphate pathway.

  4. None of the above.

Show answer
Correct Option: D
Explanation:

All the processes occur in the absence of oxygen i.e., anaerobic condition. 

So the correct option is 'None of the Fermentation or EMP pathway or Pentose phosphate pathway.'

Which is not pentose?

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Erythrose

  2. Ribose

  3. Xylose

  4. Arabinose

Show answer
Correct Option: A
Explanation:

The pentose sugars ribose and deoxyribose are part of the nucleotides that make up the crucial nucleic acids like DNA and RNA. So the correct option is 'Erythrose'.

Which one of the following hormone never reaches to cytoplasm?

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Estrogen

  2. FSH

  3. Progesterone

  4. Testosterone

Show answer
Correct Option: B
Explanation:

FSH is a proteinaceous hormone. It does not enter its target cells, thus, it never reaches to cytoplasm. Instead, it binds to the receptor present on the cell membrane and activates a membrane bound enzyme that causes conversion of ATP to cAMP. This then alters the activities of enzyme in the cytoplasm.

Last ${e}^{-}$ acceptor during ETS is 
hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. ${O} _{2}$

  2. cyt $a$

  3. cyt ${a} _{2}$

  4. cyt ${a} _{3}$

Show answer
Correct Option: A
Explanation:

In electron transport chain, there are 7 electron acceptors, which are as follows $Co-Q\rightarrow Cyt\,\, b\rightarrow Cyt \,\,{c} _{1} \rightarrow Cyt \,\,c\rightarrow Cyt \,\,a\rightarrow Cyt \,\,{a} _{3}\rightarrow{O} _{2}$. Oxygen is the ultimate electron acceptor. These electron acceptors are present in a specific sequence along inner mitochondrial membrane.

Anaerobic respiration in plants yields lactic acid.

biology respiration do plants breathe? plant respiration respiration-plants

  1. True

  2. False

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Correct Option: B

Aerobic respiration is more advantageous than anaerobic respiration because

biology respiration fermentation cell respiration living organisms and energy production

  1. It requires oxygen

  2. It produces more energy

  3. It causes complete breakdown of respiratory substrate

  4. Aerobic respiration produces water.

Show answer
Correct Option: B
Explanation:

The oxidative breakdown of respiratory substrates with the help of atmospheric oxygen is known as aerobic respiration. It involves a complete breakdown of substrates into carbon dioxide and water releasing energy. The energy released per mole of glucose is 686 Kcal or 2870 kJ. 

Oxidation of respiratory substrates in the absence of atmospheric oxygen is termed as anaerobic respiration. It involves an incomplete breakdown of respiratory substrates in which the end products such as ethanol or lactic acid are produced and carbon dioxide is released. The amount of energy released in this case is 247 kJ.
Since the energy released is more in aerobic respiration, it is more advantageous. Thus, the correct answer is option B.