All Free Biology MCQs with Answers
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19844 questions · page 516 of 1985
5151. Which of the following reagents helps us to distinguish between methanoic acid and ethanoic acid?
- A. Litmus solution
- B. Tolien's reagent
- C. Alcoholic AgNO3
- D. Sod. bicarbonate
Explanation: The correct reagent that helps distinguish between methanoic acid and ethanoic acid is B) Tolien's reagent (Fehling's solution B).
Correct answer: Tolien's reagent5152. The sequence of the amino acids combined in a peptide chain is referred to as the_ of protein:
- A. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Explanation: The correct term used to refer to the sequence of amino acids in a peptide chain that makes up the protein is A) Primary structure.
Correct answer: Primary structure5153. The_ structure of a protein is a regular coiling or zigzagging of polypeptide chains caused by hydrogen bonding between \ NH and C = O groups of amino acids near each other in-the chains.
- A. Primary structure
- B. Secondary structure
- C. Tertiary structure
- D. Quaternary structure
Explanation: The correct term used to describe the regular coiling or zigzagging of polypeptide chains caused by hydrogen bonding between NH and C=O groups of amino acids near each other in the chains is B) Secondary structure.
Correct answer: Secondary structure5154. All of the following co-factors correctly match with their resective enzyme EXCEPT:
- A. Option A
- B. Option B
- C. Option C
- D. Option D
Explanation: The mismatched cofactor and enzyme pair is D) Vitamin B1 (Thiamine) with glucosephosphatase. The correct name of the enzyme should be glucose-6-phosphatase, and vitamin B1 (Thiamine) is not a cofactor for this enzyme.
Correct answer: Option D5155. Which of the following is an example of a derived protein?
- A. Collagen
- B. Oligopeptides
- C. Lipoprotein
- D. Laetoglobulin
Explanation: Lipoproteins are examples of derived proteins. They are complexes of proteins and lipids (fats) that transport lipids through the bloodstream. Lipoproteins are essential for the transport of cholesterol and other lipids in the body.
Correct answer: Lipoprotein5156. The specific substance (metabolite) that fits on the enzyme surface and is converted to products is called:
- A. Co-factor
- B. Prosthetic group
- C. Isoenzyme
- D. Substrate
Explanation: The specific substance (metabolite) that fits on the enzyme surface and is converted to products is called substrate.
Correct answer: Substrate5157. Which one of the following is not called "food factor"?
- A. Proteins
- B. Carbohydrates
- C. Lipids
- D. Nucleic acids
Explanation: Nucleic acids are not called "food factors" because they are not used for energy or building tissues. They are the molecules that makeup DNA and RNA, which are responsible for storing genetic information.
Correct answer: Nucleic acids5158. The enzyme that catalyze the transfer of groups within molecules to yield isomeric forms is called:
- A. Lyase
- B. Ligase
- C. Hydrolase
- D. Isomerase
Explanation: Isomerase enzymes catalyze the rearrangement of atoms within molecules. This can involve the conversion of one isomer to another or the conversion of a molecule to its mirror image. For example, the enzyme glucose-phosphate isomerase catalyzes the conversion of glucose-6-phosphate to fructose-6-phosphate.
Correct answer: Isomerase5159. Collagen proteins are present in_throughout the body.
- A. Muscles
- B. Red blood cells
- C. Tendons
- D. Blood plasma
Explanation: Collagen is the most abundant protein in the body, making up about 30% of all protein. It is found in many different tissues throughout the body, including tendons, bones, skin, muscles, and cartilage. Tendons are tough, fibrous cords that connect muscles to bones. They are made up of mostly collagen, which gives them their strength and flexibility.
Correct answer: Tendons5160. Which of the following derivatives of carboxylic acid is used as flavouring agent?
- A. Acid halides
- B. Acid carbonyls
- C. Esters
- D. Acid amides
Explanation: Esters are the most common type of carboxylic acid derivative used as flavoring agents. They are found in a wide variety of foods, including fruits, vegetables, and dairy products. Some common esters used as flavoring agents include ethyl acetate (banana), methyl salicylate (wintergreen), and vanillin (vanilla).
Correct answer: Esters