Free Biological Molecules MCQs with Answers
1,790 Biological Molecules MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The chapter covers water's polarity and biological roles, carbohydrates, lipids, proteins and nucleic acids, including their monomers, bonds, structures and functions. It also distinguishes RNA from DNA and explains conjugated molecules such as glycoproteins, glycolipids and nucleoproteins, which combine organic molecules with a non-protein component.
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- A. Nucleotide
- B. Nucleoside
- C. Nucleic Acid
- D. Polynucleotide
Explanation: Nucleosides are the structural subunit of nucleic acids such as DNA and RNA.
Correct answer: Nucleoside1682. Ester linkages occur in:
- A. Nucleic acids
- B. Nucleus
- C. Carbohydrates
- D. Proteins
Explanation: DNA and RNA are the chain of polynucleotides, that are joined by ester linkage known as 'phosphodiester bonds'.
Correct answer: Nucleic acids- A. Photolysis
- B. Condensation
- C. Deduction
- D. Convection
Explanation: Condensation is a chemical reaction where two molecules combine to form a larger molecule, typically accompanied by the release of water.
Correct answer: Condensation- A. Lipids.
- B. Caseins.
- C. Formaldehydes.
- D. Nucleoproteins.
Explanation: DNA is the genetic material, where a gene is a functional unit of DNA. Chromosomes are the carrier molecules for DNA that help in the…
Correct answer: Nucleoproteins.- A. Protein
- B. Lipid
- C. Glycoproteins
- D. Vitamins
Explanation: Glycoproteins are proteins that have carbohydrate chains (glycans) attached to them.
Correct answer: Glycoproteins1686. Tay-Sach''s disease is due to the presence of an enzyme that is inverted in the catabolism of:
- A. Proteins
- B. Ascorbic Acid
- C. Carbohydrates.
- D. Lipids
Explanation: Explanation:Tay Sach disease is a lipid storage disease. The enzyme absent is involved in catabolism of lipids.
Correct answer: Lipids1687. Fatty acid are the organic compounds containing hydrogen, oxygen and one of the following are:
- A. -COOH
- B. -NH2
- C. Acyl
- D. Sucrose
Explanation: A fatty acid consists of a straight chain of an even number of carbon atoms, with hydrogen atoms along the length of the chain and at one…
Correct answer: -COOH- A. Fatty acids and water
- B. Fatty acids and alcohols
- C. Fatty acids and glucose
- D. Fatty acids and phosphates
Explanation: Acyl-glycerols, such as fats and oils, are esters formed by a condensation reaction between fatty acids and alcohols.
Correct answer: Fatty acids and alcohols- A. Phospholipids
- B. Waxes
- C. Terpenoids
- D. Acylglycerols
Explanation: Cutin in leaves and exoskeleton of insects is made up of wax. Cutin and suberin are complex bio polyesters composed of fatty acids and…
Correct answer: Waxes- A. Triglycerides
- B. Phospholipids
- C. Waxes
- D. Terpenoids
Explanation: Phospholipids are soluble in both water and oil (amphiphilic) because the hydrocarbon tails of two fatty acids are still hydrophobic, but…
Correct answer: Phospholipids- A. Stearic Acid
- B. Palmitic Acid
- C. Butyric Acid
- D. Oleic Acid
Explanation: Oleic acid is a mono-unsaturated omega-9 fatty acid found in various animal and vegetable sources.
Correct answer: Oleic Acid- A. Higher proportion of C-H
- B. Higher proportion of C-O
- C. Higher proportion of Oxygen
- D. Low proportion of C-H bonds
Explanation: C-H bond is a stronger bond than the C-O bond, and since lipids contain a much higher proportion of C-H bonds than carbohydrates (because…
Correct answer: Higher proportion of C-H- A. 6
- B. 2
- C. 4
- D. 8
Explanation: Fatty acids are organic molecules consisting of a hydrocarbon chain with a carboxylic acid group (-COOH) at one end.
Correct answer: 4- A. Ester bond
- B. Ether linkage
- C. Hydrogen bond
- D. Ionic bond
Explanation: When glycerol (a type of alcohol) reacts with fatty acids (which contain carboxyl groups), an ester bond is formed through a dehydration…
Correct answer: Ester bond- A. Glycerol
- B. Amine group
- C. Fatty Acid
- D. Phosphate group
Explanation: The phosphate group (-PO₄³⁻) in phospholipids is part of the molecule's hydrophilic head.
Correct answer: Phosphate group- A. Globular proteins
- B. Fibrous proteins
- C. Glycoproteins
- D. Glycolipids
Explanation: Explanation:This is a fact. Antibiotics are actually Globular proteins.
Correct answer: Globular proteins- A. 11000 atoms
- B. 10000 atoms
- C. 6600 atoms
- D. 6800 atoms
Explanation: Explanation:Each molecule of Haemoglobin is made up of nearly 10,000 atoms and it is 68000 times heavier than a hydrogen molecule.
Correct answer: 10000 atoms- A. -C-N
- B. -C-O
- C. -C-P
- D. -C-S
Explanation: The peptide bond is the bond formed when the carboxyl group reacts with an amide group forming a -C-N- bond.
Correct answer: -C-N- A. 20
- B. 170
- C. 25
- D. 200
Explanation: Many naturally occurring amino acids have been found however, only 20 of those types are known to be found in the proteins making up the…
Correct answer: 20- A. R group
- B. Disulfide bond
- C. Amino group
- D. Hydrogen bond
Explanation: The α-helix is a right-handed helix with the peptide bonds present on the inside and the side chains extending outward.
Correct answer: Hydrogen bond