Question

Arrange the following compounds in descending order on the basis of number of carbon atoms present in them
Palmitic acid (B) Serine (C)Ribose (D)Arachidoric acid (E) Glucose
1. D C A B E
2. B C E A D
3. D A E C B
4. C B A D E

Answer 1

Hint:The compounds belong to the various groups of biomolecules. Both arachidonic acid and palmitic acid are unsaturated and saturated fatty acids.

Complete answer:
A. Palmitic acid or hexadecanoic acid in the IUPAC nomenclature is the most common saturated fatty acid found in animals , plants and microorganisms. The empirical formula is $\rm{C_{16}H_{32}O_2}$ and C: D is 16:0. As its name suggests, it is a major component of oil derived from palm oil (palm oil). Palmitic acid can also be present in meat, cheese , butter and other dairy products. Palmitates are palmitic acid salts and esters.
B. Serine (symbol Ser or S) is an $\alpha$-amino acid that is used in protein biosynthesis. It comprises a $\alpha$-amino acid(which is in the proton ${−NH_3}^+$ form under biological conditions), a carboxylic group (which is in the deprotonated ${– COO}^-$ group).The empirical formula is $\rm{C_3H_7NO_3}$. Shape under biological conditions) and a side chain consisting of a hydroxymethyl group, which classifies it as polar amino acid.
C. Ribose is a basic sugar and carbohydrate containing the molecular formula $\rm{C_5H_{10}O_5}$. The naturally occurring type, d-ribose, is a part of the ribonucleotides from which the RNA is produced and is therefore essential for the coding, decoding, regulation and expression of genes.
D. In the chemical structure, arachidonic acid is a carboxylic acid with a 20-carbon chain and four cis-double bonds; the first double bond is the sixth carbon from the omega end.The empirical formula is $\rm{C_{20}H_{32}O_2}$.
E. Glucose is a basic sugar with the molecular formula $\rm{C_6H_{12}O_6}$. Glucose is the most common monosaccharide, a subcategory of carbohydrates. Glucose is mainly produced by plants and most algae during photosynthesis from water and carbon dioxide, using sunlight energy, where it is used to create cellulose in the cell walls, which is the most abundant carbohydrate.

Arachidonic acid- 20 C
Palmitic acid - 16 C
Glucose - 6 C
Ribose - 5 C
Serine - 3 C

Thus, the correct answer is option 3.

Note:
What you may not know, though, is that about 18% of your body (by weight) is made of carbon. In reality, carbon atoms are the backbone of many important molecules in your body, including proteins , DNA, RNA, sugars, and fats.