All Free Biology MCQs with Answers
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19844 questions · page 493 of 1985
4921. How many types of amino acids are present in the cell?
- A. 170
- B. 25
- C. 20
- D. 3000
Explanation: 170 amino acids are present in nature in cells or tissues. 25 types of amino acid are constituents of proteins. The combinations of 20 types of amino acids can synthesize most of the proteins.
Correct answer: 1704922. A globular protein consisting of more than one polypeptide chains has:
- A. Primary structure
- B. Tertiary structure
- C. Secondary structure
- D. Quaternary structure
Explanation: The quaternary structure of a protein refers to the arrangement of multiple polypeptide chains (subunits) to form a functional protein complex. In some globular proteins, two or more polypeptide chains come together and interact through various forces like hydrogen bonding, disulfide bridges, and hydrophobic interactions to form a larger functional unit. This overall arrangement of multiple subunits constitutes the quaternary structure.
Correct answer: Quaternary structure4923. Most cellular secretions are:
- A. Phospholipids
- B. Glycoproteins
- C. Nucleoproteins
- D. Glycolipids
Explanation: B is correct. Most cellular secretions are glycoproteins in nature.
Correct answer: Glycoproteins4924. There are four test tubes with starch compounds. After some time, substance Y is added in all test tubes. The first 3 test tubes showed blue color but no change in color was shown in test tube 4. What would be the compound that was already present in test tube 4?
- A. Amylase
- B. Iodine
- C. Lipase
- D. Glycogen
Explanation: A is correct. Amylase broke down the starch and hence it showed negative test for starch.
Correct answer: Amylase4925. Fats containing unsaturated fatty acids are usually represented by:
- A. Oils
- B. Solid fats
- C. Butter
- D. Banaspati
Explanation: Oils are made up of unsaturated fatty acids and are usually liquids at room temperature. Unsaturated fatty acids are also liquids at room temperature.
Correct answer: Oils4926. A phosphatidic acid upon combining with a choline gives rise to:
- A. Phosphatidic acid
- B. Phosphatidylcholine
- C. Phospholipids
- D. Phosphatidylserine
Explanation: A phosphatidic acid upon combining with a choline gives rise to phosphatidylcholine. It is the most common phospholipid in nature. It consists of glycerol, two fatty acids, a phosphoric acid, and choline.
Correct answer: Phosphatidylcholine4927. The most abundant organic compounds to be found in the cells are:
- A. Proteins
- B. Lipids
- C. Nucleic acids
- D. Carbohydrates
Explanation: Proteins being a major structural organic biomolecule at any level of biological organization constitutes more than 50% of the dry weight of organic biomass and maintain the basic fabric of the structure of cells, tissues, and organs.
Correct answer: Proteins4928. Usually a polypeptide chain bends and folds upon itself forming globular shape to acquire:
- A. Primary configuration
- B. Secondary configuration
- C. Tertiary configuration
- D. Quaternary configuration
Explanation: A globular three-dimensional structure formed by a single polypeptide chain will be a tertiary protein, because quaternary protein is also globular but it requires more than one polypeptide chains.
Correct answer: Tertiary configuration4929. Glycoproteins & glycolipids are structural integral component of:
- A. Ribosome
- B. Golgi bodies
- C. Cell wall
- D. Plasma membrane
Explanation: Cell surface markers are glycoprotein and glycolipid in nature and are present on cell membrane.
Correct answer: Plasma membrane4930. Phosphatidic acid lacks :
- A. Fatty acids
- B. Glycerol
- C. Phosphate group
- D. Choline
Explanation: Phosphatidic acid is composed if 1 glycerol 2 fatty acid and 1 phosphoric acid. Phospatidic acid combines with nitrogenous base (serine,choline,ethanaloamine) to form phospholipids
Correct answer: Choline