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 82 of 90
- A. Increase in saturated fatty acids in the membrane
- B. Increase in glycolipid content in the membrane
- C. Increase in phospholipid content in the membrane
- D. Increase in unsaturated fatty acids in the membrane
Explanation: The absence or decrease of double bonds, decreases the fluidity, making the membrane strong and rigid.
Correct answer: Increase in saturated fatty acids in the membrane- A. Palmitic acid
- B. Stearic acid
- C. Acetic acid
- D. Linolenic acid
Explanation: Here the most suitable answer will be acetic acid. Other molecules shown resemble fatty acids; they all have long hydrocarbon chains with…
Correct answer: Acetic acid- A. Hydrogen bonds
- B. Ionic bonds
- C. Peptide bonds
- D. Glycosidic bonds
Explanation: Amino acids are linked together by peptide bonds. A glycosidic bond or glycosidic linkage is a type of covalent bond that joins a…
Correct answer: Peptide bonds- A. Primary, secondary, tertiary and quaternary
- B. Primary, secondary and tertiary only
- C. Primary and quaternary only
- D. Quaternary only
Explanation: We are told that we have 2 chains of amino acids that are forming the enzyme (since it is formed by 2 chains, we know it has a quaternary…
Correct answer: Primary, secondary, tertiary and quaternary- A. H
- B. CH2OH
- C. CH3
- D. NH2
- E. OH
Explanation: Explanation for this question will be added soon.
Correct answer: CH3- A. Between Alpha C of one monomer and Carboxyl group of another monomer
- B. Between Alpha C's of both monomers
- C. Between Alpha C of one monomer and Amino group of another monomer
- D. Between carboxyl group of one monomer and amino group of another monomer
- E. None of the above
Explanation: Explanation for this question will be added soon.
Correct answer: Between carboxyl group of one monomer and amino group of another monomer- A. 4 Polypeptide chains + 4 Heme portions
- B. 4 Polypeptide chains + 1 Heme portions
- C. 1 Polypeptide chains + 4 Heme portions
- D. 1 Polypeptide chains + 1 Heme portions
Explanation: Myoglobin is a 17-kDa protein found in cardiac and red muscle tissues for oxygen storage.
Correct answer: 1 Polypeptide chains + 1 Heme portions- A. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Explanation: Primary structure, is simply the sequence of amino acids in a polypeptide chain.
Correct answer: Primary structure- A. Pepsinogen
- B. Casein
- C. Enzyme
- D. Collagen
Explanation: Collagen is the main structural protein in the extracellular matrix found in the body's various connective tissues.
Correct answer: Collagen- A. Elastin
- B. Keratin
- C. Collagen
- D. Histone
Explanation: Collagen is a fibrous protein that provides structural support and forms the matrix of tissues like bone and cartilage.
Correct answer: Collagen- A. Water
- B. Lipids
- C. Carbohydrates
- D. Proteins
Explanation: The most abundant organic compound in mammalian cells is protein
Correct answer: Proteins- A. Acid
- B. Base
- C. Neutral
- D. None of these
Explanation: In an acidic medium, amino acids can carry a positive charge by losing a proton (H+) from their amino group (NH2).
Correct answer: Base- A. To enable them to respond to environmental alterations
- B. To assemble the monomers to form a coordinated polymeric structure.
- C. In the case of enzymes, to improve their rate of catalysis.
- D. None of the above.
Explanation: Option A: To enable them to respond to environmental alterations: Some proteins with quaternary structure can undergo conformational…
Correct answer: To assemble the monomers to form a coordinated polymeric structure.- A. Hydrophilic
- B. Hydrophobic
- C. Basic
- D. Acidic
Explanation: In an aqueous environment, the most stable tertiary conformation of a protein is usually one in which the hydrophobic amino acids are…
Correct answer: Hydrophobic1635. Protein contains _.
- A. Inorganic bonds
- B. Peptide bonds
- C. Glucosidic bonds
- D. Covalent bonds
Explanation: The basic unit of protein are amino acids. There are approximately 20 types of amino acids found in our body.
Correct answer: Peptide bonds- A. Fibrous
- B. Structural
- C. Enzymatic
- D. All of the Above
Explanation: Fibrin is a fibrous protein and specifically, it is the main component of blood clots.
Correct answer: Fibrous- A. Lipids
- B. DNA
- C. RNA
- D. Protein
Explanation: A peptide is a short string of numerous amino acids, formed by a condensation reaction, joining together through a covalent bond.
Correct answer: Protein- A. 20
- B. 24
- C. 23
- D. 25
Explanation: Scientists now recognize twenty-two amino acids as the building blocks of proteins: the twenty common ones and two more, selenocysteine…
Correct answer: 20- A. Globular
- B. Functional
- C. Fibrous
- D. Both A and B
Explanation: Antibodies are both globular and functional proteins. They are globular because they are not crystalline and they have a specific…
Correct answer: Both A and B- A. Ionic
- B. Hydrogen
- C. Peptide
- D. Glycosidic
Explanation: The tertiary structure of proteins are connected by monomers of amino acid by the peptide bond.The structure is composed of hydrogen…
Correct answer: Glycosidic