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 21 of 90
- A. 4
- B. 8
- C. 2
- D. 1
Explanation: Hemoglobin consists of 4 polypeptide chains and there is one haem group in each chain which can hold one oxygen molecule (two atoms), thus…
Correct answer: 8- A. 170
- B. 20
- C. 25
- D. 3000
Explanation: Around 170 amino acids are found to be present in living cells and tissues.
Correct answer: 170- A. Alanine
- B. Serine
- C. Ethanolamine
- D. Aspartic acid
Explanation: The simplest amino acid is glycine in which R is a 'H' atom. Alanine is next to glycine which contains -CH3 as its R-group.
Correct answer: Alanine- A. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Explanation: In many complex proteins, polypeptide tertiary chains are aggregated and held together by hydrophobic interactions, hydrogen and ionic…
Correct answer: Quaternary structure- A. Hydrogen bonding
- B. Disulfide bond
- C. Peptide bond
- D. Both A and C
Explanation: All proteins have primary structure; amino acids are joined with each other through peptide bonds.
Correct answer: Both A and C- A. Silk fiber
- B. Keratin
- C. Myoglobin
- D. Fibrin
Explanation: Silk fiber, keratin and fibrin are examples of fibrous proteins while myoglobin has a tertiary structure and is a typical water soluble…
Correct answer: Myoglobin- A. Collagen
- B. Albumin
- C. Fibrinogen
- D. Haemoglobin
Explanation: Hemoglobin consists of 4 polypeptide chains forming a quaternary structure, and 4 haem groups containing 4 iron atoms as a non-protein…
Correct answer: Haemoglobin- A. Nicotine adenine dinucleotide.
- B. Flavin adenine dinucleotide.
- C. Nicotinamide adenine dinucleotide phosphate.
- D. All of the above options are correct.
Explanation: Flavin adenine dinucleotide (FAD) is a non-protein group that is covalently bonded to a few respiratory enzymes, among others.FAD is a…
Correct answer: Flavin adenine dinucleotide.- A. Antigens
- B. Antibodies
- C. Vaccines
- D. Fibrinogen
Explanation: Antibodies are also called immunoglobulins, they are the part of the immune system and protect the body against invading pathogens.
Correct answer: Antibodies- A. Storage Protein
- B. Enzymatic Protein
- C. Structural Protein
- D. Hormonal Protein
Explanation: Usually fibrous proteins containing secondary structure are structural proteins.
Correct answer: Structural Protein- A. Antibodies
- B. Fibrin
- C. Haemoglobin
- D. Enzymes
Explanation: Fibrin is an example of fibrous protein and cannot non-crystalline. Antibodies, hemoglobin and enzymes are globular proteins and can be…
Correct answer: Fibrin- A. 49
- B. 50
- C. 51
- D. 48
Explanation: There are two polypeptide chains in insulin. One containing 21 amino acids and the other containing 30 amino acids.
Correct answer: 49- A. Carbohydrates
- B. Proteins
- C. Lipids
- D. Nucleic acids
Explanation: Through metabolism carbohydrates, lipids and proteins all can be the source of energy, while nucleic acids are not the source of energy.
Correct answer: Nucleic acids- A. Glycogen
- B. ATP
- C. Cellulose
- D. Haemoglobin
Explanation: ATP is a nucleotide which contains pentose sugar, nitrogenous base and three phosphate groups.
Correct answer: ATP- A. Nucleotide
- B. Nucleoside
- C. DNA
- D. RNA
Explanation: Nucleoside is only made up of pentose sugar and nitrogenous base.
Correct answer: Nucleoside- A. DNA
- B. ATP
- C. RNA
- D. NAD
Explanation: ATP is a single nucleotide. Phosphodiester bond is present between nucleotides.
Correct answer: ATP- A. Dipole nature, Thermo-stabilizer
- B. Organic, Inorganic
- C. Polar, Bipolar
- D. Ionic, Covalent
Explanation: Water is an excellent solvent for polar substances due to its dipole nature.
Correct answer: Dipole nature, Thermo-stabilizer- A. Thermo-stabilizer
- B. Solvent
- C. Inert medium
- D. Reactive medium
Explanation: Water has great ability to absorb heat with minimum change in its own temperature due to higher heat capacity and act as thermal-stabilizer.
Correct answer: Thermo-stabilizer- A. Hormones
- B. Inhibitors
- C. Antibodies
- D. Vitamins
Explanation: Because many of the coenzymes are derived from the vitamins, e.g. NAD is a coenzyme and is derived from vitamins.
Correct answer: Vitamins- A. Substrate
- B. Enzyme
- C. Activator
- D. Inhibitor
Explanation: Addition of more substrate molecules will replace inhibitors, and will bind with the active site of the enzyme and results in an increase…
Correct answer: Substrate