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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- A. Extracellular
- B. Intracellular
- C. Both of these
- D. Glucose
Explanation: Glycolipids and glycoproteins contribute carbohydrate-containing structures to the extracellular matrix and cell surface, where they help…
Correct answer: Extracellular- A. C55H70O5N4Mg
- B. C55H72O6N4Mg
- C. C55H70O6N4Mg
- D. C55H72O5N4Mg
Explanation: The molecular formula of chlorophyll b is C55H70O6N4Mg, with magnesium held in the porphyrin-like ring and six oxygen atoms present.
Correct answer: C55H70O6N4Mg283. Which of the statement is not true for compounds like glycoprotein and glycolipids____________?
- A. They are conjugated molecules of carbohydrates
- B. Both have role in the extra cellular matrix of animals and bacterial cell wall
- C. They are components of biological membranes.
- D. Both are produced and secreted by endoplasmic reticulum
Explanation: Glycoproteins and glycolipids are carbohydrate-containing conjugated molecules found in membranes and in important extracellular…
Correct answer: Both are produced and secreted by endoplasmic reticulum- A. Fe2+
- B. Mg2+
- C. Zn2+
- D. Cu2+
Explanation: Chlorophyll is a magnesium-containing porphyrin pigment, so Mg2+ occupies its central position and helps absorb light energy.
Correct answer: Mg2+- A. Carotenes
- B. Carotenoids
- C. Xanthophylls
- D. Chlorophyll
Explanation: Carotenes are carotenoid pigments that commonly produce red, orange or orange-yellow colours and contain only carbon and hydrogen.
Correct answer: Carotenes- A. Epidermis
- B. Adipose tissue
- C. Liver
- D. Epithelium
Explanation: Most long-term fat storage occurs in adipose tissue, whose cells store triglycerides in large lipid droplets and also provide insulation…
Correct answer: Adipose tissue- A. Hormones
- B. Chemicals
- C. Cholesterol
- D. Carbohydrates
Explanation: Steroids are a class of lipids formed from the four-ring structure of cholesterol, which serves as their main precursor.
Correct answer: Cholesterol- A. cholesterol
- B. waxes
- C. chitin
- D. all of these
Explanation: Waxes are lipids that form water-resistant protective coatings on the surfaces of leaves and fruits, reducing water loss and blocking…
Correct answer: waxes- A. paralysis
- B. oedema
- C. mental retardation
- D. all of these
Explanation: In some lipid-storage disorders, lipids accumulate in brain cells and damage neurons, causing progressive mental impairment or mental…
Correct answer: mental retardation- A. Natural lipid
- B. Neutral lipid
- C. Neutral wax
- D. All of these
Explanation: A triglyceride is formed when glycerol combines with three fatty acids, and it is called a neutral lipid because it has no charged ionic…
Correct answer: Neutral lipid- A. Organic acid
- B. Alcohol
- C. Water
- D. Sugar
Explanation: During esterification, the hydroxyl group that remains in the ester-forming reaction comes from the alcohol, while the acid contributes…
Correct answer: Alcohol- A. C-6
- B. C-25
- C. C-26
- D. C-30
Explanation: Fatty acids in ordinary acylglycerols generally have an even number of carbon atoms because they are assembled from two-carbon units…
Correct answer: C-25- A. Liquids
- B. Gases
- C. Solids
- D. None of these
Explanation: Animal fats usually contain a high proportion of saturated fatty acids, whose straight chains pack closely and remain solid at room…
Correct answer: Solids- A. Acetic acid
- B. Butyric acid
- C. Palmitic acid
- D. All have same
Explanation: Palmitic acid has the longest hydrocarbon chain among the choices, so its nonpolar part interacts well with organic solvents, and its…
Correct answer: Palmitic acid- A. They contain double bond
- B. They are usually solid at room temperature
- C. They are lighter than water
- D. Their specific gravity is less than 1Exploring Local Private K-12 Schools
Explanation: Unsaturated fatty acids contain one or more double bonds that introduce bends in their chains, preventing tight packing and making their…
Correct answer: They are usually solid at room temperature- A. Saturated Fatty acid
- B. Unsaturated fatty acid
- C. Oleic Acid
- D. Plamitic acid
Explanation: Oleic acid is an 18-carbon fatty acid with one double bond, written as C18:1.
Correct answer: Oleic Acid- A. C-C bonds
- B. C-H bonds
- C. C-N bonds
- D. C-O bonds
Explanation: Lipids contain many reduced C-H bonds, and oxidation of these bonds releases substantial energy; this is why fats yield about twice as…
Correct answer: C-H bonds- A. Water
- B. Ether
- C. All solvents
- D. Not in any of the above
Explanation: Lipids are largely nonpolar, so they dissolve in nonpolar organic solvents such as ether but do not dissolve well in polar water.
Correct answer: Ether- A. Hydrophilic Carbohydrates
- B. Hydrophobic fats.
- C. Both a and b
- D. None of these
Explanation: Membrane structure is based mainly on amphipathic lipids, whose hydrophobic portions form the interior barrier and whose hydrophilic…
Correct answer: Hydrophobic fats.- A. carbohydrates
- B. proteins
- C. lipids
- D. carbonates
Explanation: Proteins contain nitrogen because their amino acids have amino groups, written as -NH2, in addition to carbon, hydrogen, and oxygen.
Correct answer: proteins