Free Biological Molecules MCQs with Answers

• A. Lecithin a phosphorylated glyceride found in the cell membrane.
• B. Palmitic acid ­an unsaturated fatty acid with 18 carbon atoms.
• C. Adenylic acid adenosine with a glucose phosphate molecule.
• D. Alanine amino acid­ contains an amino group and an acidic group anywhere in the molecule.

Explanation: Lecithin is a triglyceride lipid where one fatty acid is replaced by phosphoric acid, which is linked to an additional nitrogenous group…

• A. A: Lecithin - A component of cell membrane
• B. B: Adenine - A nucleotide that makes up nucleic acids
• C. A: Triglyceride - Major source of energy
• D. B: Uracil - A component of DNA

Explanation: A is the formula of Lecithin. Lecithin is a phospholipid and is the component of the cell membranes.

• A. (1), (3) and (5)
• B. (1) and (5)
• C. (2) and (3)
• D. (2) and (4)

Explanation: Starch is the major storage carbohydrate of plants. In most plant species it is accumulated in the chloroplast of leaves, whereas in…

• A. Calcium and Phosphorus
• B. Phosphorus and Sulphur
• C. Sulphur and Magnesium
• D. Magnesium and Sodium

Explanation: 98% body mass of a living organism is composed of C H O N P ANd S according to New sindh text book

• A. Alanine
• B. Asparagine
• C. Glycine
• D. Tyrosine

Explanation: Glycine is considered the simplest amino acid as it has one amino group, one carboxylic group, and no substituent functional group.

• A. Base­ sugar ­phosphate
• B. Base ­sugar­ OH
• C. Base­s
• D. Sugar ­phosphate

Explanation: Each nucleotide consists of three distinct units ­ a phosphate group derived from phosphoric acid, a pentose sugar, and a ring-shaped…

• A. Some bacteria, algae and green plant cells
• B. Fungi, algae and green plant cells
• C. All bacteria, fungi and algae
• D. Viruses, fungi and bacteria.

Explanation: Carbohydrates are organic compounds synthesized in the chlorophyll-containing cells of some bacteria, algae, and green plant cells, during…

• A. Co­factors of enzymes
• B. Building blocks of important amino acids
• C. Constituent of hormones
• D. Binder of cell structure

Explanation: Minor elements are those which are required in the quantity of less than milligram/gram of dry matter, but they are essential for proper…

• A. Hydrophilic
• B. Hydrophobic
• C. Neutral
• D. Zwitter ions

Explanation: Lipid molecules are insoluble or sparingly soluble in water but are freely soluble in organic solvents like ether, alcohol, and benzene.

• A. Glycoprotein
• B. Chromoprotein
• C. Lipoprotein
• D. Nucleoprotein

Explanation: Glycoproteins are proteins that contain sugars like carbohydrates as a prosthetic group.

• A. Branched-chain of glucose molecules linked by B-1,4 glycosidic bonds in straight-chain and Alpha­1,6 glycosidic bonds at the site of branching
• B. Unbranched chain of glucose molecules linked by b­1, 4 glycosidic bond
• C. Branched-chain of glucose molecules linked by Alpha-1,6 glycosidic bonds at the site of branching
• D. Unbranched chain of glucose molecules linked by a­1, 4 glycosidic bond

Explanation: Cellulose is the most abundant carbohydrate. Cellulose molecule is composed of 1600 to 6000 glucose molecules joined together.

• A. Glucose + Galactose
• B. Fructose + Galactose
• C. Glucose + Fructose
• D. Glucose + Glucose

Explanation: Lactose is popularly known as milk sugar. It is a disaccharide composed of one molecule of glucose and one molecule of galactose.

• A. Lipids
• B. Mineral salts
• C. Proteins
• D. Carbohydrates

Explanation: Proteins show enormous diversity because of different proportions and sequences of twenty amino acids within the protein molecule.

• A. Thymine
• B. Uracil
• C. Cytosine
• D. Guanine

Explanation: The bases are of two types­: purines and pyrimidines. The purine derivatives adenine (A) and guanine (G) are double ring structures…

• A. GCUAGACAA
• B. GATCAATGC
• C. UAGCGGUAA
• D. Both A and C

Explanation: In DNA and RNA, these bases form hydrogen bonds with their complementary purines.

• A. C, H, O, P, Mg and Fe
• B. C, N, O, P, Mn and Cl
• C. H, O, C, N, Ca and P
• D. C, H, O, S, Fe, Ca

Explanation: Carbon, hydrogen, oxygen, and nitrogen are called the four big elements of the living body as they make up about 99% of the mass of most…

• A. Galactose
• B. Glucose
• C. Fructose
• D. Sucrose

Explanation: Glycogen (animal starch) is a polysaccharide. It is a highly branched polymer of glucose occurring in animal tissues, especially in liver…

• A. Mineral salts
• B. Fatty acids
• C. Volatile acids
• D. A-ketoglutaric acid.

Explanation: Amino acids are mostly synthesized from a­-ketoglutaric acid. These are the precursors of amino acids.

• A. DNA
• B. RNA
• C. Chloroplasts
• D. Phagosomes

Explanation: RNA occurs in the nucleus as well as in the cytoplasm of the eukaryotic cells and in a prokaryotic cell, it is found in the cytoplasm.

• A. 60 - 65%
• B. 50 - 55%
• C. 75 - 80%
• D. 65 - 70%

Explanation: Water is the most abundant substance of living beings. The water content of actively living cells varies between 60-95%.