Tag: carbohydrate metabolism

Questions Related to carbohydrate metabolism

Which one of the following produces more energy per glucose molecule?

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Alcoholic fermentation

  2. Glycolysis

  3. Pentose phosphate pathway

  4. Lactic acid fermentation

Show answer
Correct Option: C
Explanation:

Glycolysis is a common pathway between the aerobic and anaerobic respiration. The net amount of ATP formed during glycolysis is two.

Alcoholic fermentation and lactic acid fermentation are both of pathways involved in the anaerobic respiration in which the pyruvic acid formed after glycolysis is converted into lactic acid or ethanol and carbon dioxide. The energy released during anaerobic respiration is much less as compared to the aerobic respiration.
So the correct option is, 'pentose phosphate pathway'

Which of the following pairs of structure and functions are correctly matched?
a. Tendril- Climbing
b. Penumatophore - Respiration
c. Stratospheric - checking UV or beta
d. Ozone shield - UV rays
Select the correct answer using the codes given.

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. $2$ and $3$ only

  2. $1$ and $2$ only

  3. $1$ and $3$ only

  4. $1, 2$ and $3$

Show answer
Correct Option: A

In hexose monophosphate shunt, the net formation of ATP molecules is

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. 36

  2. 35

  3. 38

  4. 34

Show answer
Correct Option: A
Explanation:

Hexose monophosphate shunt is an alternative pathway to glycolysis or the tricarboxylic acid cycle for glucose oxidation. It occurs in the cytoplasm and has two phases; the oxidative phase and the non-oxidative phase. 

This is the only process that generates reduced NADPH₂ which act as the reducing agent in the biosynthetic processes.
6 glucose molecules that enter hexose monophosphate shunt, produces 12 NADPH₂ and 6 carbon dioxide.
12 NADPH₂ molecules when undergo ETS forms  36 molecules of ATP.
So, the correct option is '36'


Which of the following is not a pathway that relates to generation of ATP?

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Pentose phosphate shunt

  2. Embden-Meyerhof pathway

  3. Oxidative-phosphorylation

  4. Photosynthesis

Show answer
Correct Option: A
Explanation:

  • Pentose phosphate shunt is the pathway that is used for the synthesis of a 5 carbon molecules such as ribose and deoxyriose which can be used for the synthesis of nucleotides, no ATP is produced during this reaction.
  • EMP pathway is the glycolysis process where 2 ATP are produced at the end of the reaction.
  • Oxidative phosporylation is the pathway that is used to reduce the NADH and FADH for the formation of ATP
  • And photosynthesis is the pathway in the plant that is used for the production of the carbohydrates that are used in the catabolic pathway for the synthesis of the ATP in cellular respiration.
  • Therefore the correct answer is option is 'Pentose phosphate shunt'.











Production of $NADPH _2$ is not linked with ATP generation in

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. Photorespiration

  2. Light recation

  3. Hexose monophosphate pathway

  4. Dark reaction

Show answer
Correct Option: C
Explanation:

Hexose monophosphate pathway (HMP) or pentose phosphate shunt is an alternate glucose metabolism that occurs in adipose tissues, liver, erythrocytes, testes, adrenal glands, mammary glads etc. This pathway is performed to generate the $NADPH _2$ to facilitate the cholesterol synthesis, steroid and lipid production and fatty acid synthesis. Thus signifying that HMP pathway readily takes place in tissues associated with lipogenesis like liver and adipose tissue. It is not linked with ATP generation. Also, the ribose sugars generated are used in DNA and RNA and many nucleotides like $ATP$, $FADH _2$ $CoA$ etc.

Photorespiration, light reaction and dark reaction are associated with phosphorylation.
Hence, the correct answer is 'Hexose monophosphate pathway'

Match the column I and II-

Column-I Column-II Site of pathway
(A) Fatty acid oxidation (p) Cytoplasm
(B) Pyruvate oxidation (q) Mitochondrial matrix
(C) Fatty acid synthesis (r) Mitochondrial inner membrane
(D) Pentose phosphate pathway (s) Glyoxysome
hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. A $\rightarrow$ p, B$\rightarrow$ q, C$\rightarrow$ r, D$\rightarrow$ s

  2. A $\rightarrow$ q, B$\rightarrow$ p, C$\rightarrow$ p, D$\rightarrow$ p

  3. A$\rightarrow$ p, B$\rightarrow$ r, C$\rightarrow$ q, D$\rightarrow$ s

  4. A $\rightarrow$ p, B$\rightarrow$ q, C$\rightarrow$ q, D$\rightarrow$ p

Show answer
Correct Option: B
Explanation:

Answer is B.


A. Fatty acid oxidation - (q) Mitochondrial matrix

B. Pyruvate oxidation  -(p) Cytoplasm
C. Fatty acid synthesis - (p) Cytoplasm
D. Pentose phosphate pathway-(p) Cytoplasm. 

Warburg-Dickens pathway is also known as

hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

  1. P.P.P.

  2. TCA cycle.

  3. EMP pathway.

  4. None of the above.

Show answer
Correct Option: A
Explanation:

Pentose phosphate pathway (PPP) is variously called as Warburg-Dickens pathway and hexose monophosphate shunt. This metabolic pathway had been discovered through a number of experiments of Lippman, Warburg (1935) and Dickens (1938). 

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.