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 47 of 90
- A. Glycerol + 2 Fatty acid + Phosphoric acid
- B. Glycerol + Fatty acid + Phosphoric acid + N-base
- C. 2 Glycerol + Fatty acid + Phosphoric acid
- D. Glycerol + Fatty acid + 2 Phosphoric acid + N-base
Explanation: Phosphatidic acid is a crucial intermediate in lipid biosynthesis and serves as a fundamental building block for phospholipids.
Correct answer: Glycerol + 2 Fatty acid + Phosphoric acid- A. mRNA
- B. DNA
- C. tRNA
- D. rRNA
Explanation: The correct answer is tRNA. Transfer RNA (tRNA) has a characteristic cloverleaf structure formed by its secondary structure, which…
Correct answer: tRNA923. Glucose is:
- A. Aldose hexose sugar
- B. Furanose pentose sugar
- C. Ketose hexose sugar
- D. Pyranose Pentose sugar
Explanation: Glucose is classified as an aldose hexose sugar because it contains an aldehyde group (making it an aldose) and has six carbon atoms…
Correct answer: Aldose hexose sugar- A. Two Monosaccharides
- B. No Monosaccharides
- C. 2-9 Monosaccharides
- D. Numerous monosaccharides
Explanation: Oligosaccharides are carbohydrates that, upon hydrolysis, yield between 2 to 9 monosaccharide units.
Correct answer: 2-9 Monosaccharides925. Reducing sugars are:
- A. Glucose, fructose, galactose, maltose, and lactose
- B. Glucose, sucrose, and cellulose
- C. Lactose, starch, glycogen, and trehalose
- D. Sucrose
Explanation: Reducing sugars are those sugars that can donate electrons to another chemical, effectively reducing it, while they themselves become…
Correct answer: Glucose, fructose, galactose, maltose, and lactose- A. Erythrose
- B. Ribulose
- C. Heptose
- D. Ribose
Explanation: The correct answer is Ribose. Deoxyribose is similar to ribose but lacks an oxygen atom at the second carbon.
Correct answer: Ribose- A. Fructose
- B. Sucrose
- C. Glucose
- D. Monellin
Explanation: Fructose is the sweetest naturally occurring carbohydrate and is significantly sweeter than both glucose and sucrose.
Correct answer: Fructose928. Deoxyribose is:
- A. C5H10O5
- B. C6H12O6
- C. C5H10O4
- D. C6H12O5
Explanation: Deoxyribose is represented by the formula C5H10O4, indicating it is a 5-carbon sugar with one less oxygen atom than ribose, which has the…
Correct answer: C5H10O4- A. Glucose
- B. Fructose
- C. Glucose & Fructose
- D. Glucose & Galactose
Explanation: Maltose is a disaccharide composed of two glucose molecules. When hydrolyzed by the enzyme maltase, it breaks down into two glucose…
Correct answer: Glucose- A. Fats
- B. Typhoid
- C. Malaria
- D. Carbohydrates
Explanation: The iodine test is a chemical test for the presence of starch, a type of carbohydrate.
Correct answer: Carbohydrates- A. 5
- B. 6
- C. 3
- D. 7
Explanation: The correct answer is 6. A pyranose ring is a six-membered structure in organic chemistry, consisting of five carbon atoms and one oxygen…
Correct answer: 6- A. Maltose, Sucrose, Lactose
- B. Glycogen, Lactose, Sucrose
- C. Maltose, Lactose, Glucose
- D. All of the above
Explanation: The correct answer is Option A: Maltose, Sucrose, Lactose. Each of these is a disaccharide, composed of two linked monosaccharides.
Correct answer: Maltose, Sucrose, Lactose- A. C3
- B. C5
- C. C1
- D. C2
Explanation: The correct answer is C1 because α and β-glucose differ in the orientation of the hydroxyl (-OH) group at the anomeric carbon, which is…
Correct answer: C1- A. Fructose
- B. DHAP
- C. Lactose
- D. PGA
Explanation: The correct answer is Lactose. Lactose is a disaccharide sugar consisting of glucose and galactose.
Correct answer: Lactose- A. Pentose
- B. Erythrose
- C. Tetrose
- D. Hexose
Explanation: The correct answer is pentose because ribose, a pentose sugar, is a component of RNA, which is synthesized in the nucleolus.
Correct answer: Pentose- A. 3
- B. 1
- C. 2
- D. 0
Explanation: A phospholipid molecule is a type of lipid that forms the basic structure of cell membranes.
Correct answer: 2- A. Phospholipid
- B. Cholesterol
- C. Steroid
- D. Waxes
Explanation: The correct answer is phospholipids. They are the most abundant lipids in cell membranes and are essential for forming the lipid bilayer…
Correct answer: Phospholipid- A. Proteins
- B. Fats
- C. Nucleic acids
- D. Carbohydrates
Explanation: Fats provide the most energy in metabolic processes because they yield approximately 9 kcal per gram, which is more than proteins and…
Correct answer: Fats- A. Oxalosuccinate
- B. Linolenic acid
- C. Oleic acid
- D. α -ketoglutarate
Explanation: Oleic acid is a monounsaturated fatty acid belonging to the omega-9 fatty acid family.
Correct answer: Oleic acid- A. Met
- B. Arg
- C. Val
- D. Tryp
Explanation: The correct answer is Methionine (Met), which is the amino acid that universally initiates protein synthesis in eukaryotic cells.
Correct answer: Met