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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1,790 questions · page 43 of 90
- A. Hormones
- B. Enzymes
- C. Hemoglobin
- D. Proteins
Explanation: Proteins are polymers of amino acids linked together by peptide bonds. They are essential biological molecules with diverse functions…
Correct answer: Proteins- A. Carbon, nitrogen, oxygen, hydrogen
- B. Carbon, nitrogen, sulphur, oxygen, hydrogen
- C. Carbon, sulphur, oxygen, hydrogen
- D. Carbon, nitrogen, sulphur, oxygen
Explanation: Amino acids, the building blocks of proteins, are primarily composed of carbon, nitrogen, oxygen, and hydrogen.
Correct answer: Carbon, nitrogen, oxygen, hydrogen- A. Central carbon
- B. Major carbon
- C. Alpha carbon
- D. Beta carbon
Explanation: The correct answer is alpha carbon. In amino acids, the alpha carbon is the central carbon atom to which the key functional groups-amino…
Correct answer: Alpha carbon- A. Functional, Amino
- B. Amino, Amino
- C. Carboxyl, Carboxyl
- D. Carboxyl, Amino
Explanation: The correct answer is Carboxyl, Amino. The peptide bond is formed when the carboxyl group of one amino acid reacts with the amino group of…
Correct answer: Carboxyl, Amino845. Peptide bond is a:
- A. C-O bond
- B. C-N bond
- C. C-C bond
- D. C-O-P bond
Explanation: A peptide bond is a covalent linkage formed between the carbon atom of the carboxyl group of one amino acid and the nitrogen atom of the…
Correct answer: C-N bond- A. Amino, Carboxyl
- B. Amino, Functional
- C. Functional, Carboxyl
- D. Amino, Amino
Explanation: A dipeptide consists of two amino acids joined by a peptide bond. This bond forms between the amino group of one amino acid and the…
Correct answer: Amino, Carboxyl- A. Two
- B. Three
- C. Four
- D. Five
Explanation: The four levels of protein structure are: Primary structure: The linear sequence of amino acids in a protein.Secondary structure: Local…
Correct answer: Four- A. Primary
- B. Secondary
- C. Tertiary
- D. Quaternary
Explanation: F. Sanger was pivotal in determining the primary structure of proteins, specifically the insulin protein, by establishing the precise…
Correct answer: Primary- A. Two alpha chains
- B. Two beta chains
- C. Two alpha and two beta chains
- D. Four alpha chains
Explanation: Hemoglobin is a protein found in red blood cells that carries oxygen throughout the body.
Correct answer: Two alpha and two beta chains- A. 280
- B. 282
- C. 292
- D. 290
Explanation: The correct answer is 292. Hemoglobin is composed of four protein subunits, including two alpha and two beta chains.
Correct answer: 292- A. 25 types of amino acids
- B. 20 types of amino acids
- C. Over 20 types of amino acids
- D. Less than 20 types of amino acids
Explanation: Proteins in the human body are synthesized using 20 different amino acids, which combine in unique sequences to form the vast array of…
Correct answer: 20 types of amino acids- A. A random arrangement
- B. A specific medium
- C. A specific arrangement
- D. Ascending order
Explanation: The correct answer is that a protein should have its amino acids in a specific arrangement for proper functioning.
Correct answer: A specific arrangement- A. Uremia
- B. Hypoglycemia
- C. Goiter
- D. Sickle cell anemia
Explanation: Hemoglobin stops carrying oxygen if one amino acid (glutamic acids) in beta chain is replaced by the other (valine).
Correct answer: Sickle cell anemia- A. Remain linear
- B. Lie flat
- C. Acquire coiling
- D. Acquire folding
Explanation: The correct answer is that polypeptide chains do not lie flat. The properties of amino acids, particularly the polar and nonpolar groups…
Correct answer: Lie flat- A. Hemoglobin
- B. Albumin
- C. Antibodies
- D. Collagen
Explanation: Collagen is the correct answer as it is a structural protein that forms the framework of bones, cartilage, skin, and connective tissues…
Correct answer: Collagen- A. α-helix
- B. β-helix
- C. γ helix
- D. Pi helix
Explanation: The α-helix is one of the most common secondary structures in proteins, known for its stability and regularity, due to hydrogen bonding…
Correct answer: α-helix- A. α-helix
- B. β-helix
- C. α-pleated sheet
- D. β-pleated sheet
Explanation: The example of folded secondary protein is β − pleated sheetwhich is formed by folding back of polypeptide chain.
Correct answer: β-pleated sheet- A. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Explanation: The correct answer is the tertiary structure. Tertiary structure is the overall three-dimensional shape of a single protein molecule, and…
Correct answer: Tertiary structure- A. One
- B. Two
- C. Three
- D. Four
Explanation: Tertiary structure is the overall folding of the polypeptide chain into a three-dimensional shape.
Correct answer: Three- A. Primary protein structure
- B. Secondary protein structure
- C. Tertiary protein structure
- D. Quaternary protein structure
Explanation: The quaternary structure of a protein is the most complex because it involves the organization of multiple polypeptide chains into a…
Correct answer: Quaternary protein structure