Tag: carbohydrate metabolism

Quizzes (9) Questions (178)

Questions Related to carbohydrate metabolism

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

The pentose monophosphate shunt is more advantageous than Krebs cycle as

  1. It yields more ATP

  2. Ribose sugar is released, which helps in nucleic acid formation

  3. It releases more oxygen

  4. It utilizes less oxygen
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pentose phosphate pathway is also known as HMP shunt. This pathway provides an alternative route for carbohydrate breakdown. HMP shunt produces some glycolytic intermediates like glyceraldehyde-3-phosphate and fructose-6-phosphate. These intermediates can directly involve in the glycolysis pathway and then in the Krebs cycle. The cycle provides ribose sugar which can be used for the synthesis of nucleic acids. This pathway is considered as advantageous since the ribose sugar is made available. 

Thus, the correct answer is option B. 

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Phosphogluconate shunt occurs in

  1. Mitochondria

  2. Chloroplasts

  3. Cytoplasm

  4. Both A and B
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The reactions of hexose monophosphate shunt occur exclusively in the cytoplasm and is an additional pathway of glucose metabolism which starts with glucose-6-phosphate. About 10-25% of glucose is metabolised by this pathway. In plants, it occurs both in cytosol and plastids. This pathway involves both oxidative and nonoxidative steps. The oxidative steps generate NADPH and ribose-5-phosphate and then non-oxidative steps convert ribose-5-phosphate back into glucose-6-phosphate which can be further utilized for NADPH generations by means of oxidative steps. 

Thus, the correct answer is option C. 

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

A respiratory cycle where mainly ${NADPH _2}$ are produced is 

  1. Calvin cycle

  2. Kreb's cycle

  3. EMP pathway

  4. HMP shunt
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

During Calvin cycle, $NADH _2$ are not produced. 
During Krebs cycle, 2 $NADH _2$, 1 $FADH _2$, 1GTP are produced. 
During EMP pathway 2 NADH, 2 ATP are produced. 
During HMP pathway, $NADPH _2$ are produced. So, in respiratory cycle  mainly $NADPH _2$ are produced is HMP pathway. Thus, option D is correct.

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Pentose phosphate pathway is a mode of

  1. Amphibolic pathway

  2. Anabolic pathway

  3. Aerobic respiration

  4. Anaerobic respiration
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pentose phosphate pathway is an alternative pathway to glycolysis which involves the oxidation of glucose-6-phosphate to 6-phosphogluconic acid which in turn gets converted into pentose phosphates. This pathway involve the direct oxidation of glucose-6-phosphate without entering glycolysis and hence is termed as direct oxidation. 

Thus, the correct answer is option C. 

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Which of the following is generated in the oxidative phase of pentose phosphate pathway?

  1. NADPH

  2. FADH

  3. GTP

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Pentose Phosphate Pathway is an alternative pathway to glycolysis and TCA cycle. It occurs in both prokaryotes and eukaryotes in their cytoplasm

Glucose is broken down by a series of pathways.
The pathway has 2 phases- Oxidative and Non-oxidative.
In the oxidative stage, there are 2 steps where NADP⁺ gets converted to NADPH.
1. Glucose 6-phosphate converts to 6-phosphogluconolactone
2. 6-phosphogluconate converts to Ribulose 5- phosphate
So, the correct option is 'NADPH'

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Pentose phosphate pathway takes place only in the

  1. Cytoplasm

  2. Mitchondria

  3. Peroxisome

  4. Chloroplast
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The pentose phosphate pathway is a metabolic pathway which is carried out in most of the organisms. This pathway occurs parallel to glycolysis. This pathway produces pentoses from glucose 6-phosphate. The pathway takes place in the cytoplasm in most of the organisms. In the case of plants, there are certain reactions which occur in the plastids.

Thus, the correct answer is option A. 

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Pentose phosphate pathway takes place only in the

  1. Cytoplasm.

  2. Mitochondria.

  3. Peroxisome.

  4. Chloroplast.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
The pentose phosphate pathway is a metabolic pathway which is carried out in most of the organisms. This pathway occurs parallel to glycolysis. This pathway produces pentoses from Glucose 6-phosphate. The pathway takes place in the cytoplasm in most of the organisms. In the case of plants, there are certain reactions which occur in the plastids.
Thus, the correct answer is option A. 
Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

An enzyme used in pentose phosphate pathway is

  1. RUBP.

  2. Aldolase.

  3. Pyruvate kinase.

  4. Phosphogluconate dehydrogenase.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In the pentose phosphate pathway 6-Phosphogluconate dehydrogenase (6PGD) is an enzyme that produces NADPH by converting 6-phosphogluconate to ribulose 5-phosphate. NADPH is used for lipid production. Thus the correct answer is option D.

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

Consider the following statements.


a. The Pentose Phosphate Pathway supplies Erythrose-$4$-Phosphate which is the starting material the synthesis on lignin.
b. The Pentose Phosphate pathway also occurs in plastids.
c. NADPH is generated by the Pentose phosphate pathway

Which of the statements given are correct?

  1. $a$ and $b$ only
  2. $a$ and $c$ only
  3. $b$ and $c$ only
  4. $a, b$ and $c$
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The Pentose Phosphate Pathway (PPP) produces Erythrose-4-phosphate, which is a precursor for aromatic amino acids and lignin biosynthesis. It occurs in the cytosol and in plastids (such as chloroplasts), and it generates NADPH as a primary reducing equivalent.

Multiple choice hmp shunt alternative to glycolysis carbohydrate metabolism respiration bio-chemistry

The substrate for pentose phosphate pathway is

  1. Glucose 6-phosphate.

  2. Glucose 1-phosphate.

  3. Fructose 6-phosphate.

  4. Fructose 1-phosphate.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Pentose Phosphate Pathway runs parallel to glycolysis and takes place in the cytoplasm. The oxidation steps, utilizing glucose-6-phosphate (G6P) as the substrate, occur at the beginning of the pathway and are the reactions that generate NADPH and also give five carbon compound for glycolysis.

So the correct option is 'Glucose 6-phosphate'.