Carbohydrates & Nucleic Acids — NEET Biology MCQs with Solutions
Free NEET Biology Carbohydrates & Nucleic Acids MCQs with step-by-step solutions (6 questions). Part of Biomolecules. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Carbohydrates & Nucleic Acids · easy · theory
The most abundant carbohydrate (and organic macromolecule) in nature, forming plant cell walls, is:
A. Cellulose ✓ Correct
B. Chitin
C. Starch
D. Glycogen
Solution: Cellulose (a homopolymer of glucose) is the most abundant polysaccharide; it forms plant cell walls.
Q2 — Carbohydrates & Nucleic Acids · easy · theory
The nitrogenous bases in DNA are adenine, guanine, cytosine and:
A. Thymine ✓ Correct
B. Xanthine
C. Uracil
D. Hypoxanthine
Solution: DNA contains thymine; in RNA, uracil replaces thymine.
Q3 — Carbohydrates & Nucleic Acids · medium · theory
The bond joining monosaccharide units in a polysaccharide is a ______ bond:
A. Peptide
B. Phosphodiester
C. Glycosidic ✓ Correct
D. Ester
Solution: Glycosidic bonds link sugar residues; nucleotides are joined by phosphodiester bonds and amino acids by peptide bonds.
Q4 — Carbohydrates & Nucleic Acids · medium · theory
A nucleotide consists of a nitrogenous base + a ______ sugar + a phosphate group:
A. Tetrose
B. Hexose
C. Triose
D. Pentose ✓ Correct
Solution: Nucleotides contain a pentose (ribose in RNA, deoxyribose in DNA); base + sugar (without phosphate) is a nucleoside.
Q5 — Carbohydrates & Nucleic Acids · hard · theory
Purines and pyrimidines differ structurally in that purines (adenine, guanine) are:
A. Both contain phosphate
B. Both single-ringed
C. Single-ringed, pyrimidines double-ringed
D. Double-ringed, while pyrimidines are single-ringed ✓ Correct
Solution: Purines (A, G) have a fused double-ring; pyrimidines (C, T, U) have a single six-membered ring.
Q6 — Carbohydrates & Nucleic Acids · hard · theory
The linkage between the two strands of DNA is by ______ bonds between complementary bases (A=T, G≡C):
A. Hydrogen ✓ Correct
B. Phosphodiester
C. Peptide
D. Glycosidic
Solution: The two antiparallel strands are held by hydrogen bonds (2 between A–T, 3 between G–C); the backbone is joined by phosphodiester bonds.