Chapter 9

Which of the following acts as a genetic material? (a) DNA and RNA (b) Uridylic acid (c) Adenylic acid (d) Guanylic acid

Sugar + Nitrogen bases form (a) Nucleoside (b) Nucleotide (c) Peptide (d) Glycoside

Sugar + Nitrogen bases + Phosphate forms (a) Nucleoside (b) Nucleotide (c) Peptide (d) Glycoside

How many Nitrogen atoms are present in adenine? (a) 3 (b) 4 (c) 5 (d) 6

DNA and RNA are (a) Polypeptides (b) Polynucleotides (c) Polysaccharides (d) All of these

Which of the following are purines? (a) Adenine (b) Guanine (c) Cytosine (d) Both (a) and (b)

Which of the following are pyramidine (substituted)? (a) Cytosine (b) Thymine (c) Uracil (d) All of these

DNA contains (a) Ribose (b) 3' deoxyribose (c) 5 ' deoxyribose (d) 2 ' deoxyribose

The bond present between two nucleotides is known as (a) Phosphoester linkage (b) Phosphodiester linkage (c) Glycosidic linkage (d) Peptide linkage

The Watson-Crick Structure of DNA is (a) \(1^{\circ}\) structure (b) \(2^{\circ}\) structure (c) \(3^{\circ}\) structure (d) \(4^{\circ}\) Structure

Which of the following is correct about DNA? (a) Double helical structure in which two strands of polynucleotide runs antiparallel. (b) Backbone is formed by Sugar-Phosphate-Sugar chain. (c) \(\mathrm{N}_{2}\) -bases projected more or less perpendicular to back bone and faces inside. (d) All of these

Which one is correct about DNA? (a) DNA exist as double helix. (b) Two strands of polynucleotide in DNA are antiparallel. (c) The nitrogen bases are projected more or less perpendicular to this backbone but face inside. (d) All the above

At each step of an ascent in a B-DNA double helical structure, the strand turns (a) \(36^{\circ}\) (b) \(72^{\circ}\) (c) \(90^{\circ}\) (d) \(18^{\circ}\)

One full turn of B-DNA helix strand would involve how many base pairs? (a) 12 (b) 8 (c) 10 (d) 20

Select the incorrect statement from the following: (a) \(\mathrm{N}_{2}\) -bases \((\mathrm{A}, \mathrm{G}, \mathrm{C}, \mathrm{T}, \mathrm{U})\) have heterocyclic rings. (b) In most of the organisms, the DNA is genetic material. (c) Adenylic acid is nucleoside. (d) The rise per base pair in B-DNA is \(3.4 \mathrm{~A}^{\circ}\).

Plants produce an enormous diversity of substances that have no apparent roles in growth and development processes and are classified under the heading of (a) Primary metabolites (b) Secondary metabolites (c) Necessary metabolites (d) Tertiary metabolites

Which one of the following is a secondary metabolite? (a) Amino acid (b) Sugar (c) Flavonoides and antibiotics (d) Protein

Which of the following are pigments? (a) Morphine (b) Vinblastine (c) Carotenoids and anthocyanin (d) Ricin

Which one of the following is not a polymeric substance? (a) Rubber (b) Morphine (c) Protein (d) Cellulose

Which of the following secondary metabolites are used as drugs? (a) Abrin + Ricin (b) Vinblastin \(+\) Curcumin (c) Anthocyanins (d) Monoterpenes

Which one of the following is a secondary metabolite? (a) Lemon oil grass (b) Sucrose (c) Lactose (d) Glycine

Match the Column Column I Column II (Category) (Secondary Metabolites) A. Pigments 1\. Concanavalin \(\mathrm{A}\) B. Terpenoids 2\. Monoterpenes, Diterpenes C. Alkaloids 3\. Morphine, Codeine D. Lectins 4\. Carotenoids, Anthocyanine E. Toxins 5\. Abrin and Ricin F. Drugs 6\. Vinblastin, Curcumin (a) \(\mathrm{A}-1, \mathrm{~B}-2, \mathrm{C}-6, \mathrm{D}-4, \mathrm{E}-5, \mathrm{~F}-6\) (b) \(\mathrm{A}-4, \mathrm{~B}-2, \mathrm{C}-3, \mathrm{D}-1, \mathrm{E}-5, \mathrm{~F}-6\) (c) \(\mathrm{A}-3, \mathrm{~B}-4, \mathrm{C}-6, \mathrm{D}-5, \mathrm{E}-1, \mathrm{~F}-2\) (d) \(\mathrm{A}-2, \mathrm{~B}-1, \mathrm{C}-4, \mathrm{D}-6, \mathrm{E}-5, \mathrm{~F}-6\)

Which one of the following are secondary metabolites? (a) Flavonoids and rubber (b) Antibiotics, coloured pigments and essential oils (c) Scents, gums, spices (d) All the above

Select the incorrect statement from the following: (a) All biomolecules have turnover in cell. (b) Metabolic reaction does not occur in isolation. (c) Metabolic pathways are either linear or circular. (d) Metabolites flow is a steady state of body constituent.

Select the incorrect statement from the following: (a) Acetic acid becoming cholesterol is an example of biosynthetic or anabolic pathway. (b) Glucose becoming lactic acid in our skeletal muscles is an example of degradation or catabolic pathway. (c) The flow of metabolite through metabolic pathway does not have a definite rate and direction. (d) Anabolic pathway requires energy whereas catabolic pathway releases energy.

Bond energy, which is stored in our body in the form of ATP is utilized in (a) Biosynthetic phase (b) Osmotic work (c) Mechanical work (d) All of these

Select the correct statement from the following: (A) Biomolecules are in metabolic flux in living state. (B) Living process is a constant effort to prevent falling into equilibrium. (C) Metabolism provides a mechanism for the production of energy. (D) Living state and metabolism is synonymous. (a) All except \(\mathrm{A}\) (b) All except B (c) All except D (d) All of these

In how many metabolic steps the degradation of glucose to lactic acid occurs? (a) 8 (b) 9 (c) 10 (d) 2

How do living organisms derive their energy? What strategies have they evolved? How do they store this energy and in what form? How do they convert this energy into work? These aspects are studied under a sub-discipline called (a) Biowar (b) Bioinformatics (c) Bioenergetics (d) Biosynthesis

Almost all enzymes are (a) Proteins (b) Nucleic acid (c) Carbohydrates (d) Vitamins

There are some nucleic acids that behaves like enzymes and are called (a) DNase (b) RNase (c) Endonuclease (d) Ribozymes

of an enzyme is a crevices or pocket into which substrate fit. (a) Inactive site (b) Active site (c) Allosteric site (d) Any of these

Select the incorrect statement from the following: (a) Active enzyme has tertiary structure having many active sites (substrate binding sites). (b) Enzymes are biocatalyst. (c) Enzymes occur in viruses. (d) Enzymes are mainly protein in nature.

Select the correct statement from the following: (a) Inorganic catalysts work efficiently at high temperature and high pressure while enzymes get damaged at high temperature (above \(40^{\circ} \mathrm{C}\) ). (b) Ribozymes are nucleic acids behaving like enzyme. (c) Thermophilic organisms living in hot vents and sulphur springs have enzymes that are stable and retain their catalytic power even at high temperatures \(\left(80-90^{\circ} \mathrm{C}\right)\). (d) All of these

Select the incorrect statement from the following: (a) A physical change simply refers to a change in shape without breaking of bonds. (b) Change is a state of matter and it is also a physical change. (c) Hydrolysis of starch into glucose is an inorganic chemical reaction. (d) Catalyzed reactions proceed at rates vastly higher than that of uncatalyzed ones.

\(\mathrm{CO}_{2}+\mathrm{H}_{2} \mathrm{O} \Leftarrow \mathrm{H}_{2} \mathrm{CO}_{3}\) Carbonic acid Which one of the following statement is incorrect about the above reaction? (a) In the absence of enzyme, the rate of \(\mathrm{H}_{2} \mathrm{CO}_{3}\) formation is about 200 molecules per hour. (b) When carbonic anhydrase catalyses the same reaction, there is no change in the rate of \(\mathrm{H}_{2} \mathrm{CO}_{3}\) formation. (c) The reaction catalyzed by the enzyme shows dramatically higher decrease speed about 600,000 molecules being formed every second (rate becomes 10 million times more). (d) The enzymes carbonic anhydrase occurs in abundance of RBC's.

Fill in the blanks in the below statements: A. A multistep chemical reaction, when each of the steps is catalyzed by the same enzyme complex or different enzymes is called a \(1 \quad\) pathway. B. In our skeletal muscle, under anaerobic conditions, \(2 \underline{ }\) is formed. C. In yeast, during fermentation, the gylcolytic pathway leads to the production of 3 (a) 1-metabolic pathway 2-acetic acid 3 -ethanol (b) 1-glycolytic pathway 2-lactic acid 3 -ethanol (c) 1-glycolytic pathway 2-ethanol \(\quad\) 3-ethanol (d) 1 -metabolic pathway 2-lactic acid 3-ethanol

There could be many more altered structural states (like transition state) between the stable substrate and the product in enzymatic reaction. These structural states are (a) Stable (b) Unstable (c) Metastable (d) Of lower energy than both substrate and product

Which one of the following statements about enzymes is true? 1\. Enzymes are proteins whose three dimensional shape is key to their functions. 2\. Enzymes speed up reactions by lowering the activation energy. 3\. Enzymes are highly specific for reactions. 4\. Enzyme activity is affected by the change in temperature and \(\mathrm{pH}\). (a) All except 2 (b) All except 1 (c) All except 3 (d) All of these

Which of the following is a unique feature about the enzyme? (a) They are not consumed by the enzyme-mediated reaction. (b) They are not altered by the enzyme-mediated reaction. (c) They lower the activation energy. (d) All of these

The catalytic cycle of an enzyme action can be described in the following steps. Arrange them in sequence accordingly. 1\. The binding of the substrate induces the enzyme to alter its shape, fitting more tightly around the substrate. 2\. The substrate binds to the active site of the enzyme, fitting into the active site. 3\. The enzyme releases the products of the reaction and the free enzyme is ready to bind to another molecule of the substrate and run through the catalytic cycle once again. 4\. The active site of the enzyme, now in close proximity of the substrate breaks the chemical bonds of the substrate and the new enzyme product complex is formed. (a) \(1 \rightarrow 2 \rightarrow 3 \rightarrow 4\) (b) \(2 \rightarrow 1 \rightarrow 4 \rightarrow 3\) (c) \(1 \rightarrow 2 \rightarrow 4 \rightarrow 3\) (d) \(2 \rightarrow 1 \rightarrow 3 \rightarrow 4\)

Each enzyme shows its highest activity at particular temperature and \(\mathrm{pH}\) called the temperature and (2) \(\mathrm{pH}\). (a) optimum, optimum (b) minimum, minimum (c) maximum, maximum (d) minimum, maximum

Select the correct statement: (a) Low temperature preserves the enzyme in a temporarily inactive state. (b) Higher temperature destroys enzymatic activity because proteins are denatured by heat. (c) The activity of enzymes declines both below and above the optimum value. (d) All of these

Select the correct statement: (a) Increase in substrate concentration, increases the velocity of enzymatic reaction at first then it reaches maximum and further increment does not occur. (b) In competitive inhibition, the inhibitor closely resembles the substrate in its molecular structure. (c) Competitive inhibition are often used in the control of bacterial pathogens. (d) All of these

The activity of an enzyme is also sensitive to the presence of specific chemicals that bind to the enzyme. When the binding of the chemical shuts off enzyme activity, the process is called and the chemical is called an (a) activation, activator (b) inhibition, inhibitor (c) Inhibition, promoter (d) activation, inhibitor

Inhibition of succinate dehydrogenase by malonate is an example of (a) Non-competitive inhibition (b) Negative feed back (c) Allosteric inhibition (d) Competitive inhibition

Enzymes which catalyse oxidoreduction between two substrate belongs to the class (a) Oxidoreductase (b) Transferase (c) Hydrolase (d) Ligase

Enzymes which catalyse transfer of group other than hydrogen belongs to the class (a) Oxidoreductase (b) Transferase (c) Hydrolase (d) Ligase

Enzymes which catalyse hydrolysis of ester, ether, peptide, glycosidic bond belongs to the class (a) Oxidoreductase (b) Transferase (c) Hydrolase (d) Ligase

Enzymes that catalyse removal of groups from substrates by mechanisms other than hydrolysis leaving double bonds is known as (a) Oxidoreductase (b) Transferase (c) Hydrolase (d) Lyase