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. Nucleic acids
- B. Carbohydrates
- C. Lipids
- D. Proteins
Explanation: Correct option: C) Lipids are insoluble in water and soluble in organic solvents.
Correct answer: Lipids562. Lipids store double amount of energy, as compared to the equal amount of carbohydrates, because of:
- A. Higher proportion of C-H bonds
- B. Higher proportion of C-N bonds
- C. Higher proportion of C-O bonds
- D. Lower proportion of C-O-P bonds
Explanation: Correct option: A) Lipids store double the amount of energy compared to an equal amount of carbohydrates because of their higher…
Correct answer: Higher proportion of C-H bonds- A. Acylglycerols and waxes
- B. Phospholipids and sphingolipids
- C. Carotenoids and steroids
- D. Dextrins and pectins
Explanation: Correct option: D) Dextrins and pectins are not lipids.
Correct answer: Dextrins and pectins- A. Phospholipids
- B. Waxes
- C. Acylglycerols
- D. Terpenoids
Explanation: Correct option: C) Acylglycerols can be defined as esters of fatty acids and alcohol.
Correct answer: Acylglycerols- A. Acylglycerol
- B. Ester
- C. Fatty acid
- D. Wax
Explanation: Correct option: B) The compound produced as a result of a chemical reaction of an alcohol with an acid, where a water molecule is…
Correct answer: Ester- A. H, OH
- B. H, H
- C. OH, H
- D. OH, OH
Explanation: Correct option: A) During ester formation, an H (hydrogen atom) is released from the alcohol, and an OH (hydroxyl group) is released from…
Correct answer: H, OH- A. Hydrogen, an acidic group
- B. Oxygen, an alcohol
- C. Oxygen, an acid group
- D. Hydrogen, an alcohol
Explanation: Correct option: A) Fatty acids contain an even number of carbon atoms in a straight chain attached with hydrogen atoms and have an acidic…
Correct answer: Hydrogen, an acidic group- A. 2-7
- B. 3-7
- C. 2-30
- D. 2-40
Explanation: Correct option: C) The number of carbon atoms in fatty acids may range from 2 to 30.
Correct answer: 2-30- A. Unbranched, branched, ringed
- B. Branched, ringed, unbranched
- C. Ringed, branched, unbranched
- D. Ringed, unbranched, branched
Explanation: Correct option: A) In animals, fatty acids are unbranched, while in plants these can be unbranched, branched, or ringed.
Correct answer: Unbranched, branched, ringed- A. Number of carbon atoms in chain
- B. Number of oxygen atoms in chain
- C. Number of hydrogen atoms in chain
- D. Number of acid groups in chain
Explanation: Correct option: A) The solubility of fatty acids in organic solvents and their melting points increase with an increase in the number of…
Correct answer: Number of carbon atoms in chain- A. Acetic acid, butyric acid
- B. Butyric acid, palmitic acid
- C. Palmitic acid, butyric acid
- D. Palmitic acid, oleic acid
Explanation: Correct option: C) Palmitic acid is much more soluble in an organic solvent than butyric acid.
Correct answer: Palmitic acid, butyric acid- A. Oleic acid
- B. Palmitic acid
- C. Butyric acid
- D. Acetic acid
Explanation: Correct option: D) Acetic acid is the smallest fatty acid.
Correct answer: Acetic acid- A. Saturated
- B. Straight chain
- C. Unsaturated
- D. Saturated unbranched
Explanation: Unsaturated fatty acids have double bonds and less hydrogen atoms. Causing them to have weaker intermolecular forces and lower melting…
Correct answer: Unsaturated- A. Unsaturated
- B. Branched
- C. Saturated
- D. Ringed
Explanation: Saturated fatty acids have no carbon to carbon double bonds and so will form more bonds with hydrogen atoms and have straight chains.
Correct answer: Saturated- A. 0.08
- B. 0.8
- C. 0.008
- D. 8.0
Explanation: Fats are lighter than water specific gravity less than 1.0 i.e. 0.8.
Correct answer: 0.8- A. Carbohydrates
- B. Monosaccharides
- C. Fats and oils
- D. Sucrose
Explanation: Fats and oils are not crystalline but some can be crystallized under speciic conditions.
Correct answer: Fats and oils- A. NH2
- B. H
- C. COOH
- D. CH3
Explanation: Amino acids differ from each other with respect to the R group only, the rest of the components are constant.
Correct answer: CH3- A. Carboxyl group
- B. R-group
- C. Amino group
- D. Methyl group
Explanation: Amino acids differ from each other on the basis of R group or side chain, rest of the components are constant e.g.
Correct answer: R-group- A. Alanine
- B. Glycine
- C. Leucine
- D. Tyrosine
Explanation: Glycine is the simplest amino acid of nature having hydrogen as the 'R' group.
Correct answer: Glycine- A. Number of amino acids
- B. Specific sequence of the amino acids
- C. Shape of the amino acids
- D. Number and specific sequence of amino acids
Explanation: At primary structural level any change in the number and sequence of amino acids changes shape and properties of protein as well.
Correct answer: Number and specific sequence of amino acids