Question

Match the compounds given in column I with the number of carbon atoms present in them, which are listed under column II. Choose the answer which gives the correct combination of alphabets of the two columns.

	List I		List II
A	Oxaloacetate	p	6-C compound
B	Phosphoglyceraldehyde	q	5-C compound
C	Isocitrate	r	4-C compound
D	$\alpha$- Ketoglutarate	s	3-C compound
		t	2-C compound

• A. A- s, B- t, C- q, D- r
• B. A- r, B- s, C- p, D- q
• C. A- r, B- t, C- p, D- q
• D. A- q, B- s, C- p, D- t

Answer 1

Answer: (B)

A- r, B- s, C- p, D- q

• Oxaloacetate is an intermediate of the citric acid cycle, with four carbon atoms. It reacts with acetyl CoA to form citrate catalyzed by citrate synthase.
• Phosphoglyceraldehyde is a phosphate of glyceraldehyde that is formed especially in the anaerobic metabolism of carbohydrates by the splitting of a diphosphate of fructose. It contains 3 carbon.
• Isocitrate is a substrate of the citric acid cycle. It is formed from the citrate with the help of the enzyme aconitase and is acted upon by isocitrate dehydrogenase. It is a 6 carbon compound.
• Ketoglutaric acid is one of two ketone derivatives of glutaric acids. Its anion, alpha-ketoglutarate is an important biological compound. It is the keto acid produced by the deamination of glutamate and is an intermediate in Kreb's cycle. It is a 5-C compound.

So, the correct answer is option B.