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 14 of 90
- A. Algae
- B. Fungi
- C. Insects
- D. Protozoa
Explanation: Insects constitute the largest number of known animal species because their body plan, small size and reproductive success allow them to…
Correct answer: Insects- A. Monovalent
- B. Divalent
- C. Trivalent
- D. Tetravalent
Explanation: Carbon is tetravalent because it has four electrons in its outer shell and can form four covalent bonds.
Correct answer: Tetravalent- A. CO2
- B. Water
- C. Lipids
- D. HCI
Explanation: Lipids are organic compounds because they contain carbon-based structures and are produced by living organisms.
Correct answer: Lipids264. Which chemical component has the greatest contribution in the total mammalian cell weight__________?
- A. Proteins
- B. Carbohydrate
- C. Lipids
- D. Water
Explanation: Water usually makes up the greatest proportion of a mammalian cell's mass, commonly about 70% or more, and acts as the main solvent for…
Correct answer: Water- A. Chemistry
- B. Biochemistry
- C. Molocular biology
- D. Both a and b
Explanation: Biochemistry studies the chemical substances and chemical processes occurring in living organisms, including metabolism and the structure…
Correct answer: Biochemistry266. Which chemical component has the same % in bacterial as well as the mammalian cell_____________?
- A. Water
- B. Carbohydrate
- C. Proteins
- D. Lipids
Explanation: Water forms approximately 70% of the mass of both typical bacterial and mammalian cells, although the exact percentage varies with cell…
Correct answer: Water- A. Oxygen
- B. Hydrogen
- C. Sulphur
- D. Carbon
Explanation: Carbon is the basic element of organic compounds because its four covalent bonds allow it to form stable, diverse molecular skeletons.
Correct answer: Carbon- A. Ionic bond
- B. Hydrogen bond
- C. Covalent bond
- D. Electrovalent bond
Explanation: A covalent bond forms when atoms share one or more pairs of electrons to complete or stabilize their outer electron shells.
Correct answer: Covalent bond- A. Inorganic
- B. Cationic
- C. Anionic
- D. Organic
Explanation: Chlorophyll is an organic molecule because it is a carbon-based pigment with a complex ring structure and a magnesium ion at its centre.
Correct answer: Organic- A. Hydration
- B. Hydrolysis
- C. Dehydration synthesis
- D. Electrolysis
Explanation: Hydrolysis uses water to break a covalent bond in a large molecule, such as splitting a polymer into smaller units.
Correct answer: Hydrolysis- A. Molecular biology
- B. Physiology
- C. Biochemistry
- D. Atomic biology
Explanation: Biochemistry studies the chemical substances present in living organisms and the reactions they undergo, including metabolism and enzyme…
Correct answer: Biochemistry- A. Polysaccharide
- B. Protein
- C. Hemoglobin
- D. ATP
Explanation: ATP is a micromolecule because it is a relatively small molecule made of adenine, ribose and phosphate groups, although it transfers…
Correct answer: ATP- A. Cell nucleus
- B. DNA or RNA
- C. Cell membrane
- D. Vacuole
Explanation: All cellular living organisms contain genetic material, with DNA serving as the hereditary material and RNA functioning in gene…
Correct answer: DNA or RNA- A. Calcium
- B. Iron
- C. Water
- D. Carbohydrates
Explanation: Iron is essential because it forms the haem group of haemoglobin, which binds oxygen reversibly in red blood cells.
Correct answer: Iron- A. copper
- B. magnesium
- C. iron
- D. None of these
Explanation: Chlorophyll is a chelate in which a magnesium ion is held at the centre of a large porphyrin-like ring.
Correct answer: magnesium- A. Chromo-proteins
- B. Lipo-proteins
- C. Phospho-proteins
- D. Nucleo-proteins
Explanation: Nucleoproteins consist of nucleic acids associated with proteins, and nucleic acids such as DNA carry hereditary information.
Correct answer: Nucleo-proteins- A. Hormones
- B. Hemoglobin
- C. Red blood cell
- D. White blood cell
Explanation: Hemoglobin is an iron-containing conjugated protein because its globin protein is combined with haem groups containing iron.
Correct answer: Hemoglobin- A. Chlorophyll e
- B. Chlorophyll d
- C. Chlorophyll a
- D. Chlorophyll c
Explanation: Bacteriochlorophylls are specialized pigments of photosynthetic bacteria and include forms such as bacteriochlorophylls a, b, c, d and e.
Correct answer: Chlorophyll a- A. Glycolipids
- B. Glycoproteins
- C. Nucleohistones
- D. None of these
Explanation: Nucleohistones consist of DNA associated with histone proteins and help package DNA into chromosomes, influencing which genes are…
Correct answer: Nucleohistones- A. Glycolipids
- B. Glycoproteins
- C. Nucleohistones
- D. Proteins
Explanation: Many cellular secretions are glycoproteins, in which carbohydrate groups are attached to protein molecules; examples include several…
Correct answer: Glycoproteins