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 52 of 90
- A. 21
- B. 45
- C. 51
- D. 66
Explanation: Insulin is a protein hormone composed of 51 amino acids in two chains: the A chain with 21 amino acids and the B chain with 30 amino…
Correct answer: 51- A. α-helix
- B. β-pleated sheets
- C. Both A and B
- D. Salt bridges
Explanation: The correct answer is both α-helix and β-pleated sheets since they are the two major types of secondary structure in proteins.
Correct answer: Both A and B- A. Rubisco
- B. Collagen
- C. Cellulose
- D. Albumin
Explanation: Collagen is the most abundant protein in the human body, making up about 30% of the total protein content.
Correct answer: Collagen- A. Collagen
- B. Haemoglobin
- C. Keratin
- D. Fibrinogen
Explanation: The most abundant protein in blood is hemoglobin, which is crucial for oxygen transport in red blood cells.
Correct answer: Haemoglobin- A. Disulphide bonds
- B. Glycoside bond
- C. Hydrogen bond
- D. Peptide bond
Explanation: The correct answer is the 'Peptide bond.' Peptide bonds are the primary linkages formed between amino acids in a protein chain…
Correct answer: Peptide bond- A. Made up of 2-α and 2-β chains.
- B. Present in RBC.
- C. Used to carry O₂ & CO₂.
- D. All of these
Explanation: The correct answer is Option D: 'All of these.' Human haemoglobin is a protein made up of two alpha and two beta polypeptide chains.
Correct answer: All of these- A. Amino acids are compounds containing both an amino group (-NH₂) and a carboxyl group (-COOH)
- B. Amino acids are derivatives of methane
- C. The properties and types of amino acids are determined by the nature of their 'R' group, or side chain
- D. Both A and C are correct
Explanation: The correct answer is only A & C. Option A is correct because amino acids contain both an amino group (-NH₂) and a carboxylic acid group…
Correct answer: Both A and C are correct- A. Glycine
- B. Alanine
- C. Leucine
- D. Valine
Explanation: The correct answer is glycine. Glycine is unique among amino acids because its side chain, or R-group, is just a single hydrogen atom.
Correct answer: Glycine- A. Keratin
- B. Myosin
- C. Fibrin
- D. Hormones
Explanation: The correct answer is hormones. Hormones are biochemical messengers that are typically not proteins, and when they are, they are not…
Correct answer: Hormones- A. R-group
- B. Amino group
- C. Carboxyl group
- D. Peptide bond
Explanation: The correct answer is the R-group. Each amino acid has a central carbon atom to which four different groups are attached: an amino group…
Correct answer: R-group- A. Water
- B. Proteins
- C. Carbohydrates
- D. Lipids
Explanation: Proteins are the most abundant organic compounds in mammalian cells. They are essential for numerous cellular processes, including…
Correct answer: Proteins- A. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Explanation: The correct answer is the quaternary structure because it specifically refers to the level of protein structure where multiple polypeptide…
Correct answer: Quaternary structure- A. Blood
- B. Muscles
- C. Bones
- D. Nails and hair
Explanation: Keratin is a type of fibrous protein that is key to the structure of hair, nails, and the outer layer of skin.
Correct answer: Nails and hair- A. Having amino acids
- B. Being soluble in aqueous medium
- C. Their repeating units are joined by a peptide bond
- D. Being non-crystalline
Explanation: Globular proteins are characterized by their spherical shape and are typically soluble in aqueous solutions due to their hydrophilic…
Correct answer: Being soluble in aqueous medium1035. The peptide bond is a:
- A. C-N link
- B. C-O link
- C. N-H link
- D. C-H link
Explanation: The peptide bond is a specific type of covalent bond that occurs between two amino acids.
Correct answer: C-N link- A. Amino acids
- B. Polypeptides
- C. Enzymes
- D. Nucleic acids
Explanation: The correct answer is amino acids. Proteins are made up of amino acids, which are linked together in specific sequences to form…
Correct answer: Amino acids- A. C
- B. N
- C. S
- D. P
Explanation: The correct answer is Option D. Phosphorus is not normally present in proteins; it is a key element in nucleic acids like DNA and RNA.
Correct answer: P- A. Chitin
- B. Keratin
- C. Both
- D. None
Explanation: The correct answer is keratin. Keratin is a tough, fibrous protein that forms the structural framework of nails, horns, and hooves.
Correct answer: Keratin- A. No
- B. One
- C. Multiple
- D. Six
Explanation: Unsaturated fatty acids contain multiple double bonds because they lack the maximum number of hydrogen atoms bonded to their carbon chain…
Correct answer: Multiple- A. Hydrogen bonds
- B. Disulfide linkage
- C. Ionic bonds
- D. Peptide bonds
Explanation: The alpha helix is a common secondary structure in proteins, stabilized by hydrogen bonds.
Correct answer: Hydrogen bonds