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.
Last updated
1,790 questions · page 37 of 90
- A. Monosaccharide
- B. Fatty acid
- C. Nucleic acid
- D. Neutral lipid
Explanation: Neutral lipids, such as triglycerides, are formed when an alcohol (glycerol) reacts with fatty acids, releasing water molecules in a…
Correct answer: Neutral lipid- A. Chylomicrons
- B. VLDL
- C. LDL
- D. HDL
Explanation: LDL (Low-Density Lipoprotein) is rich in cholesterol and is often referred to as "bad cholesterol" because high levels can lead to plaque…
Correct answer: LDL- A. In heads
- B. In tails
- C. Both A and B
- D. None of these
Explanation: The tails of phospholipids are hydrophobic, meaning they avoid water, leading to the formation of bilayers.
Correct answer: In tails724. A triglyceride is:
- A. Protein
- B. Nucleic acid
- C. A simple sugar
- D. Lipid
Explanation: Triglycerides are a type of lipid, which is a category ofbiological molecules that includes fats, oils, and waxes.
Correct answer: Lipid- A. C18H34O2
- B. C18H36O2
- C. C2H4O2
- D. C16H36O2
Explanation: This is the correct molecular formula for oleic acid, a monounsaturated fatty acid with one double bond.
Correct answer: C18H34O2726. Liposomes are:
- A. Drug carriers
- B. Water in middle
- C. Sac of phospholipids
- D. All of the above
Explanation: Liposomes function as drug carriers, have a water-filled core, and are composed of phospholipid bilayers, making all the above statements…
Correct answer: All of the above- A. Lipids
- B. Haemoglobin
- C. Phospholipids
- D. Waxes
Explanation: Serine is indeed a component of phospholipids, specifically in the form of phosphatidylserine, which plays a crucial role in cell membrane…
Correct answer: Phospholipids- A. Branched chain
- B. Ring
- C. Straight chain
- D. None of these
Explanation: Fatty acids in animals are usually in a straight chain configuration, meaning they have a continuous, unbranched carbon chain.
Correct answer: Straight chain- A. 2-30
- B. 4-30
- C. 25-35
- D. 25-45
Explanation: Waxes are esters of long-chain fatty acids and long-chainalcohols. The long-chain alkanes present in waxes usuallycontain 25 to 45 carbon…
Correct answer: 25-35- A. Fatty acid and water
- B. Fatty acid and glucose
- C. Fatty acid and alcohol
- D. Fatty acid and phosphates
Explanation: Esters are formed when fatty acids react with alcohols through a condensation reaction.
Correct answer: Fatty acid and alcohol- A. 0.8
- B. 0.10
- C. 0.12
- D. 0.16
Explanation: Fats and oils are less dense than water, so they float on water. Their specific gravity is about 0.8, meaning they are lighter than water…
Correct answer: 0.8- A. Hydrolysis takes place
- B. Transpiration takes place
- C. Dehydration synthesis takes place
- D. Water is added
Explanation: Dehydration synthesis involves removing a water molecule to join two molecules, which is why the formula of maltose is C₁₂H₂₂O₁₁.
Correct answer: Dehydration synthesis takes place- A. D-galactose
- B. L-galactose
- C. L-glucose
- D. None of them
Explanation: Enantiomers are mirror images of each other that cannot be superimposed.
Correct answer: L-glucose- A. Maltose
- B. Sucrose
- C. Cellulose
- D. Cellobiose
Explanation: Maltose is a disaccharide composed of two glucose units linked by an 𝛼-1-4 glycosidic bond.
Correct answer: Maltose- A. Primary, I₂
- B. Secondary, I₂
- C. Tertiary, I₂
- D. Quaternary, I₂
Explanation: Starch forms a secondary helical structure that can trap iodine (I₂), resulting in a blue color.
Correct answer: Secondary, I₂- A. Starch
- B. Maltose
- C. Lactose
- D. Sucrose
Explanation: Sucrose is a common carbohydrate (disaccharide) composed of glucose and fructose.
Correct answer: Sucrose- A. Dihydroxyacetone
- B. Cellulose
- C. Glyceraldehyde
- D. Fructose
Explanation: Glyceraldehyde is a triose sugar with an aldehyde group, making it an aldo sugar.
Correct answer: Glyceraldehyde- A. 574 kcal/ g m
- B. 550 kcal/ g m
- C. 717.6 kcal / g m
- D. 717.6 kcal/ g ml
Explanation: The synthesis of 1gram of glucose via photosynthesis requires roughly 71.76kcal of solar energy.
Correct answer: 717.6 kcal/ g ml739. Nucleotides are building blocks of nucleic acids. Each nucleotide is a composite molecule made of:
- A. Base sugar phosphate
- B. Base sugar OH
- C. Bases
- D. Sugar phosphate
Explanation: A nucleotide is composed of a nitrogenous base, a pentose sugar, and a phosphate group.
Correct answer: Base sugar phosphate- A. Free aldehyde group
- B. Free aldehyde or ketone group
- C. Free ketone group
- D. None of these
Explanation: A reducing sugar must have a free aldehyde or ketone group that can participate in redox reactions.
Correct answer: Free aldehyde or ketone group