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 36 of 90
- A. 1 and 4
- B. 1 and 6
- C. 2 and 5
- D. 3 and 6
Explanation: The correct answer is Option C: 2 and 5. In a tripeptide, the amino acids are linked by peptide bonds.
Correct answer: 2 and 5- A. Hydrogen
- B. Copper
- C. Oxygen
- D. Carbon
Explanation: Copper is needed in small amounts by living organisms for enzymatic activity, classifying it as a trace element.
Correct answer: Copper- A. Chemistry
- B. Molecular Biology
- C. Biochemistry
- D. Both a and b
Explanation: Biochemistry is the branch of science that explores the chemical processes within and related to living organisms.
Correct answer: Biochemistry- A. Divalent
- B. Monovalent
- C. Trivalent
- D. Tetravalent
Explanation: A tetravalent atom can form four bonds. Carbon is tetravalent because it has four valence electrons that can form bonds with other atoms.
Correct answer: Tetravalent- A. 18%
- B. 19%
- C. 20%
- D. 25%
Explanation: Human bone cells contain about 20% water, which is lower compared to other body tissues like muscles and brain that have a much higher…
Correct answer: 20%- A. Cohesion
- B. Tension
- C. Adhesion
- D. Imbibition
Explanation: Adhesion is the attraction between different kinds of molecules, such as water molecules and the cell wall of xylem.
Correct answer: Adhesion- A. Pyranose
- B. Furanose
- C. Dextrorotatory
- D. Levorotatory
Explanation: "Furanose" is the term used for sugars with a five-membered ring structure, resembling the compound furan.
Correct answer: Furanose- A. Chitin
- B. Cutin
- C. Pectin
- D. Dextrin
Explanation: Cutin is a waxy polymer found in the cuticle of plants, primarily composed of fatty acids, not sugars.
Correct answer: Cutin- A. Trioses
- B. Tetroses
- C. Pentoses
- D. Hexoses
Explanation: Tetroses are four-carbon monosaccharides and are indeed rare in nature, occurring in some bacteria.
Correct answer: Tetroses- A. Starch
- B. Glycogen
- C. Cellulose
- D. All of these
Explanation: Starch reacts with iodine to produce a blue-black color due to the formation of a polyiodide complex within the helical structure of…
Correct answer: Starch- A. F. Sanger
- B. Beadle
- C. Tatum
- D. Ingram
Explanation: Vernon Ingram discovered that sickle cell anemia was caused by a specific mutation in the hemoglobin molecule, marking the first time a…
Correct answer: Ingram- A. Protein
- B. Lipid
- C. Carbohydrate
- D. Glycoprotein
Explanation: Glycoproteins are proteins that have carbohydrate groups attached to them and are commonly found in cellular secretions.
Correct answer: Glycoprotein- A. Globular
- B. Fibrous
- C. Enzymes
- D. Both A & B
Explanation: Globular proteins are spherical and soluble in water. They play dynamic roles in biological processes, such as enzymatic activity and…
Correct answer: Globular- A. 3.6
- B. 4.6
- C. 5.6
- D. 6.6
Explanation: In the α-helix structure of proteins, each complete turn of the helix contains 3.6 amino acid residues.
Correct answer: 3.6- A. Rubisco
- B. Collagen
- C. Haemoglobin
- D. Albumin
Explanation: Rubisco, short for Ribulose-1,5-bisphosphate carboxylase/oxygenase, is the enzyme responsible for fixing carbon dioxide during the Calvin…
Correct answer: Rubisco- A. Histidine
- B. Lactic acid
- C. Glutamic acid
- D. Glycine
Explanation: Lactic acid is an organic acid involved in metabolic processes, but it is not an amino acid.
Correct answer: Lactic acid- A. Hair
- B. Skin
- C. Bone
- D. Muscle
Explanation: The skin, particularly the outermost layer called the epidermis, is composed of keratinized epithelium.
Correct answer: Skin- A. Disulphide bonds
- B. Glycoside bond
- C. Hydrogen bond
- D. Peptide bond
Explanation: Peptide bonds are covalent bonds that link the carboxyl group of one amino acid to the amino group of another, forming the backbone of…
Correct answer: Peptide bond- A. -C-N-N-C-
- B. -C-O-N-C-
- C. -C-C-C-N-
- D. -N-C-C-C-
Explanation: This is the correct sequence representing the typical order of atoms in a peptide bond, with carbon atoms flanking a nitrogen atom.
Correct answer: -C-O-N-C-- A. Sphingolipids
- B. Alcohol and fatty acids
- C. Carbohydrate and sphingolipids
- D. Carbohydrates and fatty acids
Explanation: Glycosphingolipids are composed of carbohydrate groups attached to sphingolipids.
Correct answer: Carbohydrate and sphingolipids