All Free Biology MCQs with Answers
Every Biology question in the bank, across all chapters, each with the correct answer and a written explanation. Free and unlimited, with no account needed.
19,844 questions · page 920 of 993
- A. Prokaryotic cell walls contain cellulose
- B. Prokaryotic cell walls contain peptidoglycan
- C. Prokaryotic cell walls contain cutin
- D. Prokaryotic cell walls contain silica
Explanation: What distinguishes Prokaryotic cell walls from Fungal cell walls is that Prokaryotic cell walls contain peptidoglycan
Correct answer: Prokaryotic cell walls contain peptidoglycan18382. Damage to one of the following immediately kills the cell, whether it's prokaryotic or eukaryotic:
- A. Nucleus
- B. Cell membrane
- C. Mitochondria
- D. All of these
Explanation: If the cell membrane is damaged, the cell will not be able to exchange material from its surroundings by diffusion or osmosis because it…
Correct answer: Cell membrane- 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: Hydrophobic18395. 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