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. Saccharides
- B. Polyhydroxy aldehydes
- C. Polyhydroxy ketone
- D. Condensation products
Explanation: The correct answer is Saccharides. Saccharides is a term derived from the Greek word 'sakkharon', meaning sugar, and it is commonly used…
Correct answer: Saccharides- A. Three main groups
- B. Seven distinct groups
- C. Three to seven categories
- D. More than seven categories
Explanation: Carbohydrates are primarily classified into three groups: monosaccharides, oligosaccharides, and polysaccharides.
Correct answer: Three main groups- A. Polysaccharides
- B. Oligosaccharides
- C. Disaccharides
- D. Monosaccharides
Explanation: Monosaccharides, also known as simple sugars, are the most basic form of carbohydrates.
Correct answer: Monosaccharides- A. One to three
- B. One to seven
- C. Three to seven
- D. Three to thousands
Explanation: In nature, monosaccharides with three to seven carbon atoms are found which are trioses, tetroses, pentoses, heptoses and hexoses.
Correct answer: Three to seven- A. None of these
- B. Cx(H2O)y
- C. Cn(H2O)n
- D. Cy(H2O)n
Explanation: The general chemical formula for a monosaccharide is Cn(H2O)n. In this formula n represents the number of carbon atoms in the molecule.The…
Correct answer: Cn(H2O)n- A. Three
- B. Four
- C. Six
- D. Five
Explanation: Ribose forms a five-membered ring, which is also called a furanose ring. This ring consists of four carbon atoms and one oxygen atom.
Correct answer: Five- A. Three
- B. Four
- C. Five
- D. Six
Explanation: One corner is occupied by oxygen and rest of the four by carbon atoms, whereas sixth carbon remaining outside the ring.
Correct answer: Five- A. Green plants
- B. Protists
- C. Animals
- D. Fungi
Explanation: The correct answer is Green plants. Green plants are capable of photosynthesis, which allows them to convert sunlight, carbon dioxide, and…
Correct answer: Green plants- A. Trisaccharides
- B. Tetrasaccharides
- C. Pentasaccharides
- D. Disaccharides
Explanation: The correct answer is D. Disaccharides are composed of two linked monosaccharide units, and upon hydrolysis, they yield exactly two…
Correct answer: Disaccharides- A. C12H22O11
- B. C6H12O6
- C. C3H6O3
- D. C5H10O5
Explanation: Sucrose is a disaccharide formed by the condensation of glucose and fructose monomers, resulting in the removal of a water molecule (H2O).
Correct answer: C12H22O11- A. One
- B. Two
- C. Three
- D. Four
Explanation: Starches consist of two major types: amylose and amylopectin. Amylose is characterized by a linear chain of glucose molecules, while…
Correct answer: Two- A. Starch
- B. Amylopectin
- C. Cellulose
- D. Pectins
Explanation: Cotton is a pure form of cellulose, which is a polysaccharide that serves as the main structural component of plant cell walls.
Correct answer: Cellulose- A. Bacteria
- B. Yeasts
- C. Protozoa
- D. Bacteria, Yeasts, and Protozoa
Explanation: In herbivores, the digestion of cellulose is primarily facilitated by bacteria and protozoa present in their digestive systems.
Correct answer: Bacteria, Yeasts, and Protozoa- A. Genetic material
- B. Cell wall
- C. Cytoplasm
- D. Cellular membrane
Explanation: The correct answer is Option D: Cellular membrane. Lipids, particularly phospholipids, are integral to the structure of cellular…
Correct answer: Cellular membrane- A. Lipids
- B. Carbohydrates
- C. Nucleic acids
- D. Proteins
Explanation: The correct answer is Option A: Lipids. Lipids provide thermal insulation by forming a barrier that reduces heat exchange, allowing…
Correct answer: Lipids- A. Phospholipids or sphingolipids
- B. Glycerolipids or fatty acids
- C. Triglycerides or neutral lipids
- D. Steroids or cholesterol
Explanation: The correct answer is Option C: Triacylglycerols are also called triglycerides or neutral lipids.
Correct answer: Triglycerides or neutral lipids- A. Acylglycerol
- B. Triglyceride
- C. Monoglyceride
- D. Diacylglycerol
Explanation: The correct answer is Option B: Triglyceride. Triglycerides are composed of one glycerol molecule and three fatty acids, making them the…
Correct answer: Triglyceride- A. No double bond
- B. Presence of multiple double bonds
- C. Low melting point
- D. Commonly found in plant fats
Explanation: The correct option is A) No double bond. Unsaturated fatty acids are defined by the presence of one or more double bonds in their carbon…
Correct answer: No double bond- A. 61.3oC
- B. 63.1oC
- C. 80oC
- D. -8oC
Explanation: Butyric acid is a short-chain fatty acid with four carbon atoms, which results in a relatively low melting point of approximately -8°C.
Correct answer: -8oC- A. Oleic acid
- B. Palmitic acid
- C. Butyric acid
- D. Acetic acid
Explanation: The correct answer is Butyric acid, which is a saturated fatty acid with 4 carbon atoms, as indicated by the 'but-' prefix in its name.
Correct answer: Butyric acid