Free Biological Molecules MCQs with Answers
1,790 Biological Molecules MCQs from Biology, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
The chapter covers water's polarity and biological roles, carbohydrates, lipids, proteins and nucleic acids, including their monomers, bonds, structures and functions. It also distinguishes RNA from DNA and explains conjugated molecules such as glycoproteins, glycolipids and nucleoproteins, which combine organic molecules with a non-protein component.
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1,790 questions · page 18 of 90
- A. Primase
- B. Polymerase
- C. Helicase
- D. Ligase
Explanation: DNA ligase joins Okazaki fragments on the lagging strand by sealing breaks in the sugar-phosphate backbone and forming phosphodiester…
Correct answer: Ligase- A. Polarity
- B. Cohesion
- C. Heat of vaporization
- D. Specific heat capacity
Explanation: The correct answer is polarity. Water molecules have a polar structure, meaning there is an uneven distribution of electron density.
Correct answer: Polarity- A. Being an excellent solvent
- B. Cooling agent
- C. Membrane stabilizer
- D. Thermal shock resistor
Explanation: Due to its high heat capacity, water is used by warm blooded animals to more evenly disperse heat in their bodies; it acts in a similar…
Correct answer: Cooling agent- A. 15 to 16
- B. 16 to 18
- C. 15 to 20
- D. 25 to 29
Explanation: The specific heat capacity is defined as the quantity of heat (J) absorbed per unit mass (kg) of the material when its temperature…
Correct answer: 15 to 16- A. Universal solvent
- B. Polar nature
- C. Hydrogen bonding
- D. Becomes denser when it freezes.
Explanation: The statement in option (d) is false and not a property of water. Water actually becomes less dense when it freezes.
Correct answer: Becomes denser when it freezes.- A. Heat of vapourization
- B. Specific heat capacity
- C. Heat of ionization
- D. Polarity of water
Explanation: The heat of vaporization is the amount of heat energy required to convert a unit mass of a substance (in this case, water) from its liquid…
Correct answer: Heat of vapourization- A. Tension.
- B. Cohesion.
- C. Adhesion.
- D. Ambibition.
Explanation: Cohesion: Hydrogen bonds make water sticky. Water has an amazing ability to adhere (stick) to itself and to other substances.
Correct answer: Cohesion.- A. High specific heat capacity
- B. Hydrogen bonding
- C. Cohesion and tension
- D. Hydrophobic exclusion
Explanation: Hydrophobic exclusion cause water molecules to be repelled by the hydrophobic tails of phospholipids, causing them to cluster around the…
Correct answer: Hydrophobic exclusion- A. A
- B. B
- C. C
- D. None of these
Explanation: Option A is the hypertonic solution, as it causes the cells to shrink due to the movement of water out of the cell towards the higher…
Correct answer: A- A. Isotonic
- B. Hypotonic
- C. Hypertonic
- D. Hyposmotic
- E. Hyperosmotic
Explanation: The human body maintains an isotonic environment, which means that the concentration of solutes is equal inside and outside of the cells.
Correct answer: Isotonic- A. Muscle cells
- B. Bone cells
- C. Brain cells
- D. None of the above
Explanation: The correct answer is brain cells. Brain cells, or neurons, have a high water content of approximately 85%, which is vital for their role…
Correct answer: Brain cells- A. Heat of neutralization of water
- B. Heat of condensation of water
- C. Heat of vaporization of water
- D. Specific heat of water
Explanation: The specific heat of water is a measure of the amount of heat energy needed to raise the temperature of one gram of water by 1°C.
Correct answer: Specific heat of water- A. With the release of large amount of water, a small amount of heat loss can take place.
- B. With the release of small amount of water vapours, a great amount of heat loss can take place.
- C. It will keep their temperature very high.
- D. No cooling effect, with the release of even a large amount of water vapours.
Explanation: As per the formula Q=mL, since water has a high latent heat of vaporization (L), for a small mass or amount of water (m), a large amount…
Correct answer: With the release of small amount of water vapours, a great amount of heat loss can take place.- A. Solute particles from higher concentration to lower concentration
- B. Solvent particles from higher water potential to lower water potential
- C. Solute particles from higher concentration to lower concentration through a semipermeable membrane
- D. Solvent particles from lower water potential to higher water potential
Explanation: Osmosis is the movement of water molecules from an area of high water potential to an area of low water potential through a semi-permeable…
Correct answer: Solvent particles from higher water potential to lower water potential- A. Proteins
- B. Polysaccharides
- C. Lipids
- D. Nucleic acids
Explanation: Lipids are fatty acid esters of alcohol and related substances. Polysaccharides are polymers of monosaccharides.
Correct answer: Lipids- A. Hydrogen Bonds
- B. Electrostatic Interaction
- C. Hydrophobic Interaction
- D. Ester Bonds
Explanation: Protein folding is the process by which a protein structure assumes its functional shape or conformation by allowing interaction between…
Correct answer: Ester Bonds- A. N-acetyl glucosamine
- B. Lipoglycans
- C. Keratin sulfate and chondroitin sulfate
- D. D -glucosamine
Explanation: Chitin is a structural polysaccharide that constitutes the exoskeleton of arthropods.
Correct answer: N-acetyl glucosamine- A. Sulfur-containing polysaccharide
- B. Simple polysaccharide
- C. Nitrogen containing polysaccharide
- D. Phosphorous containing polysaccharide.
Explanation: Chitin is a structural polysaccharide that constitutes the exoskeleton of arthropods.
Correct answer: Nitrogen containing polysaccharide- A. Nucleoside
- B. Nucleotide
- C. Purine
- D. Pyrimidine.
Explanation: A nucleoside is a pentose sugar and a base together, without the phosphate group. Uracil is present as uridine in RNA only.
Correct answer: Nucleoside- A. Trypsin
- B. Haemoglobin
- C. Collagen
- D. Insulin
Explanation: Collagen is an insoluble fibrous protein found extensively in the connective tissue of skin, tendons, and bone.
Correct answer: Collagen