Q.1. Which of the following glucose transporters is insulin-dependent? (2019)
(a) GLUT IV
(b) GLUT I
(c) GLUT II
(d) GLUT III
GLUT stands for glucose transport protein channel. They are of different types. Glucose transporter type 4 (GLUT IV) is a protein encoded in humans by the SLC2A4 gene. It is insulin-regulated glucose transporter found primarily in adipose tissues and striated muscles.
Q.2. Concanavalin A is (2019)
(a) A pigment
(b) An alkaloid
(c) An essential oil
(d) A lectin
Concanavalin A, a lectin is a secondary metabolite, which has no direct function in growth and development of plants, rather are found at particular stages of development.
Q.3. Consider the following statements.
(A) Coenzyme or metal ion that is tightly bound to enzyme protein is called prosthetic group.
(B) A complete catalytic active enzyme with its bound prosthetic group is called apoenzyme.
Select the correct option. (2019)
(a) (A) is false but (B) is true.
(b) Both (A) and (B) are true.
(c) (A) is true but (B) is false.
(d) Both (A) and (B) are false.
Enzymes could be simple or conjugated (holoenzyme). Conjugated enzymes are formed of two parts - a protein part called apoenzyme and a non-protein part named co-factor. Co-factors are bound to the enzyme to make it catalytically active. There are three types of cofactors : prosthetic groups, co-enzymes and metal ions.
Prosthetic groups are organic compounds and are distinguished from other cofactors in which they are tightly bound to the apoenzyme. Co-enzymes are organic compounds but their association with the apoenzyme is only transient, occurring during the course of catalysis. A number of enzymes require metal ions for their activity which form coordination one or more coordination bonds with the substrate.
Q.4. "Ramachandran plot" is used to confirm the structure of (2019)
Q.5. Prosthetic groups differ from co-enzymes in that (2019)
(a) They require metal ions for their activity
(b) They (prosthetic groups) are tightly bound to apoenzymes
(c) Their association with apoenzymes is transient
(d) They can serve as co-factors in a number of enzyme-catalyzed reactions
Q.6. The two functional groups characteristic of sugars are (2018)
(a) Hydroxyl and methyl
(b) Carbonyl and methyl
(c) Carbonyl and phosphate
(d) Carbonyl and hydroxyl
Carbohydrates (commonly called sugars) are chemically defined as polyhydroxy aldehyde or ketones. All sugar molecules have one carbonyl group (-CO-) in addition to hydroxyl group (OH) on other carbon atoms.
Q.7. Which of the following statements is correct with reference to enzymes? (2017)
(a) Holoenzyme = Apoenzyme + Coenzyme
(b) Coenzyme - Apoenzyme + Holoenzyme
(c) Holoenzyme = Coenzyme + Co-factor
(d) Apoenzyme = Holoenzyme + Coenzyme
Holoenzyme is the complete conjugate enzyme consisting of an apoenzyme and a cofactor. Cofactor may be organic or inorganic in nature. Organic cofactors are of two types-coenzyme and prosthetic group.
Q.8. Which of the following are not polymeric? (2017)
(d) Nucleic acids
Lipids are fatty acids esters of alcohols and related substances. Polysaccharides are polymers of monosaccharides. Proteins are polymers of amino acids and nucleic acids are polymer of nucleotides.
Q.9. A non-proteinaceous enzyme is (2016)
A ribozyme is a ribonucleic acid (RNA) enzyme that catalyses a chemical reaction in a similar way to that of a protein enzyme. These are found in ribosomes and are also called catalytic RNAs.
Q.10. Which of the following is the least likely to be involved in stabilising the three-dimensional folding of most proteins? (2016)
(a) Hydrogen bonds
(b) Electrostatic interaction
(c) Hydrophobic interaction
(d) Ester bonds
Tertiary structure or three dimensional structure of protein is stabilised by several types of bonds-hydrogen bonds, ionic bonds, van der Waal's interactions, covalent bonds and hydrophobic bonds.
Q.11. Which of the following describes the given graph correctly? (2016)
(a) Endothermic reaction with energy A in presence of enzyme and B in absence of enzyme.
(b) Exothermic reaction with energy A in presence of enzyme and B in absence of enzyme.
(c) Endothermic reaction with energy A in absence of enzyme and B in presence of enzyme.
(d) Exothermic reaction with energy A in absence of enzyme and B in presence of enzyme.
Q.12. A typical fat molecule is made up of (2016)
(a) One glycerol and one fatty acid molecule
(b) Three glycerol and three fatty acid molecules
(c) Three glycerol molecules and one fatty acid molecule
(d) One glycerol and three fatty acid molecules.
Neutral or true fats are triglycerides which are formed by esterification of three molecules of fatty acids with one molecule of trihydric alcohol, glycerol (glycerine or trihydroxy propane).
Q.13. Which one of the following statements is wrong? (2016)
(a) Uracil is a pyrimidine.
(b) Glycine is a sulphur containing amino acid.
(c) Sucrose is a disaccharide.
(d) Cellulose is a polysaccharide.
Glycine is a neutral amino acid. Cysteine and methionine are sulphur containing amino acid.