All Free Biology MCQs with Answers
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19844 questions · page 503 of 1985
5021. NAD contains which vitamin as cofactor.
- A. B1
- B. B2
- C. C
- D. B3
Explanation: NAD contains vitamin B3 as a cofactor. A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst.Niacin or vitamin B3 is a water-soluble vitamin.
Correct answer: B35022. Human body contains about how many kinds of proteins ?
- A. 60000
- B. 10000
- C. 5000
- D. 200
Explanation: Option B is correct since the human body probably contains at least 10,000 different kinds of proteins. They are present in muscles, skin, hair, and other tissues.
Correct answer: 100005023. In proteins, the H bonding is present between _.
- A. C-H
- B. N-H
- C. O-H
- D. Cl-H
Explanation: Proteins are made of long chains of amino acids .The long chains of amino acids are coiled around each other into a spiral called helix, helix may either be right handed or left handed. In the right handed helix, the -NH groups of one spiral form hydrogen bonds with C=O of the other.
Correct answer: N-H5024. Nucleoprotein are _ proteins which transfer heredity information from one generation to the other.
- A. Transport protein
- B. Structural protein
- C. Genetic protein
- D. Regulatory protein
Explanation: Nucleoproteins which are complexes of protein with nucleic acids serve as carriers of heredity from one generation to another and thus are referred to as genetic protein.
Correct answer: Genetic protein5025. Enzymes that catalyze hydrolysis:
- A. Oxidoreductase
- B. Hydrolases
- C. Ligases
- D. Transferases
Explanation: This option is correct because hydrolase is the enzyme which catalyses the process of hydrolysis.Hydrolysis is the process in which large molecules are broken down in the presence of water.
Correct answer: Hydrolases5026. Glucose is converted into Ethanol by the _ enzyme present in yeast.
- A. Invertase
- B. Urease
- C. Glycolysis
- D. Zymase
Explanation: A zymase enzyme present in the yeast is used to convert glucose into ethanol and carbon dioxide.
Correct answer: Zymase5027. The reaction between fats and caustic soda is called:
- A. Hydrogenolysis
- B. Fermentation
- C. Carboxylation
- D. Saponification
Explanation: Saponification is a process that involves the conversion of fat, oil, or lipid (fats in this case) into soap and alcohol by the action of aqueous alkali (caustic soda in this case).
Correct answer: Saponification5028. Adipic acid and hexamethylene diamine both of which have _ carbon atoms:
- A. 7
- B. 8
- C. 6
- D. 4
Explanation: Nylon 6,6 is made of two monomers each containing 6 carbon atoms, hexamethylenediamine, and adipic acid, which give nylon 6,6 its name.
Correct answer: 65029. Lactose is a sugar present in milk. It is an example of:
- A. Disaccharides
- B. Monosaccharides
- C. Polysaccharides
- D. Starch
Explanation: It consists of one unit of galactose plus one of glucose linked together by β-(1→4) glycosidic bond, then it is a disaccharide.
Correct answer: Disaccharides5030. Macromolecules are described as large molecules built up from small repeating units called:
- A. Monomers
- B. Isomers
- C. Metamers
- D. Tautomers
Explanation: A monomer is a molecule that "can undergo polymerization thereby contributing constitutional units to the essential structure of a macromolecule.
Correct answer: Monomers