All Free Biology MCQs with Answers
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19844 questions · page 494 of 1985
4931. Lecithin consists of:
- A. Glycerol, Fatty acids, Phosphoric acid and Choline
- B. Glycerol, Fatty acids, Phosphoric acid and Ethanolamine
- C. Glycerol, Fatty acids, Phosphoric acid and Inositol
- D. Glycerol, Fatty acids, Phosphoric acid and Serine
Explanation: Phosphatidic acid is composed if 1 glycerol 2 fatty acid and 1 phosphoric acid it combines with choline to form phosphotidyl choline also known as lecithin.
Correct answer: Glycerol, Fatty acids, Phosphoric acid and Choline4932. The covalent bond formed between two monosaccharides is called?
- A. Glycosidic bond
- B. Hydrogen bond
- C. Peptide bond
- D. Disulphide bond
Explanation: A glycosidic bond is a type of covalent bond that links a carbohydrate molecule to another group, which can be another carbohydrate or a non-carbohydrate moiety. This bond forms through a condensation reaction, also known as dehydration synthesis, where a water molecule is eliminated.
Correct answer: Glycosidic bond4933. Lipids contain double the amount of energy as compared to same amount of carbohydrates because of high proportion of:
- A. C-C bonds
- B. C-H bonds
- C. C-O bonds
- D. C-N bonds
Explanation: Lipids contain double the amount of energy as compared to same amount of carbohydrates because of high proportion of C-H bonds.
Correct answer: C-H bonds4934. In sickle cell hemoglobin, the change occurs at _ position of β chain in protein.
- A. 1st
- B. 2nd
- C. 3rd
- D. 6th
Explanation: "The explanation for this question will be added soon!".
Correct answer: 6th4935. Lactose is a disaccharide of:
- A. Glucose only
- B. Glucose and galactose
- C. Glucose and fructose
- D. All of the above
Explanation: This is correct because lactose is the disaccharide whose monomers are glucose and galactose. The glycosidic linkage between glucose and galactse in lactose is B-1,4-glycosidic.
Correct answer: Glucose and galactose4936. Ethylene is a monomer of polyethylene that is widely used as raw material for manufacturing plastics. It can be polymerized into two different classes: HDPE and LDPE. The following choices are the differences of HDPE and LDPE except:
- A. The density
- B. The branching of ethylene
- C. Reaction conditions
- D. Type of polymerization
Explanation: Ethylene is a monomer of polyethylene that is widely used as raw material for manufacturing plastics. It can be polymerized into two different classes: HDPE and LDPE. There are many differences between HDPE and LDPE but they differ highly in density, branching of ethylene, and reaction conditions such as temperature, pressure, and catalysts. On the other hand, they both undergo chain-growth polymerization or addition polymerization.
Correct answer: Type of polymerization4937. During condensation polymerization, two monomers may be joined by the removal of a molecule of:
- A. Carbon Dioxide
- B. Hydrogen
- C. Oxygen
- D. Water
- E. None of these options
Explanation: During condensation polymerization, two molecules are joined together with the removal of H2O molecules.
Correct answer: Water4938. Harmful and undesirable reaction of a metal when exposed to the atmosphere or any chemical agent is known as:
- A. Allotropy
- B. Electroplating
- C. Collision
- D. Cracking
- E. Corrosion
Explanation: The harmful and desirable reaction which occurs due to oxidation of the metal exposed to the surrounding air is called corrosion.
Correct answer: Corrosion4939. Chlorine is manufactured commercially by the electrolysis of aqueous sodium chloride (brine). Which other products are made in this process?
- A. Hydrochloric acid and hydrogen
- B. Hydrogen and sodium
- C. Hydrogen and sodium hydroxide
- D. Sodium and sodium hydroxide
- E. Hydrochloric acid and sodium
Explanation: Gas extraction: Chlorine can be manufactured by the electrolysis of a sodium chloride solution (brine), whichis known as the Chlor Alkali process. The production of chlorine results in the co-products of caustic soda (sodium hydroxide, NaOH) and hydrogen gas (H2).
Correct answer: Hydrogen and sodium hydroxide4940. Part of a polymer molecule has the following structure. -CH2 -CH2 -CH2 -CH2 -CH2 -CH2-, what will be it's monomer?
- A. C2H4
- B. C2H6
- C. C3H6
- D. C3H8
Explanation: In this process, small organic molecules (monomers) combine together to form larger molecules known as Polymers. Ethene at 400°C and 100 atm pressure, polymerize to polythene or polyethylene. Good quality polythene is obtained when ethene is polymerized in the presence of aluminum triethyl Al(C2H5) and titanium tetrachloride catalysts (TiCl4).
Correct answer: C2H4