Category: Drug & Pharmaceutical Biotechnology Objective Questions

Drug Biotechnology Multiple Choice Questions on “Tissue Binding of Drugs”.

1. What reasons make tissue-drug binding important for drug distribution?
a) Increases the volume of distribution of drugs and results in localization of drug at a specific site
b) Increases the volume of distribution of drugs
c) Results in localization of drugs at a tissue specific site
d) Increases in absorption from the tissue due to concentration increasing
Answer: a
Clarification: Tissue-drug binding is important in the distribution of drugs. This is because it increases the apparent volume of distribution of drugs in contrast to plasma protein which decreases it. Tissue-drug binding results in localization of the drug at a specific site in the body.

2. Following is the order in decreasing order of drug binding to the extravascular tissue. Which one is the correct order?
a) Liver > kidney > muscle > lung
b) Liver > muscle > lung > kidney
c) Liver > muscle > kidney > lung
d) Liver > kidney > lung > muscle
Answer: d
Clarification: Factors influencing localization of drugs are tissues lipophilicity, structure of drug, perfusion rate, pH differences etc. Drugs binding to the extracellular site has the order of binding in decreasing order liver > kidney > lung > muscle.

3. What is the relation between halogenated hydrocarbon and liver?
a) Halogenated hydrocarbon is a drug for liver problems
b) Halogenated hydrocarbon is nutrition for liver
c) Halogenated hydrocarbon causes hepatotoxicity
d) Halogenated hydrocarbon forms the bile juices in liver
Answer: c
Clarification: Epoxides of number of Halogenated hydrocarbon and paracetamol bind irreversibly to the liver tissues resulting in hepatotoxicity. Thus we are told that taking more paracetamol can damage our liver.

4. Which drugs accumulate in liver?
a) Acidic drugs like imipramine
b) Basic drugs like imipramine
c) Halogenated hydrocarbons
d) Chloroquinine
Answer: b
Clarification: Imipramine is a basic drug. Basic drug like imipramine, chlorpromazine and anti-histamines accumulate in lungs.

5. Which metals get accumulated in the kidney?
a) Mercury, cadmium, lead
b) Mercury, cadmium, iron
c) Mercury, lanthanum, lead
d) Mercury, cadmium, fluoride ions
Answer: a
Clarification: Metallothionin, is a protein present in kidneys. This protein tends to bind to heavy metals such as mercury, cadmium, lead. Resulting in their accumulation in kidney and toxicity.

6. Which of the following drugs accumulate in skin?
a) Acidic drugs like imipramine
b) Basic drugs like imipramine
c) Halogenated hydrocarbons
d) Chloroquine
Answer: d
Clarification: Skin as melanin which protects us from the harmful UV rays of the sun. Chloroquine and phenothiazines accumulate in skin by interacting with melanin.

7. Which of the following drugs are responsible for retinopathy?
a) Acidic drugs like imipramine
b) Basic drugs like imipramine
c) Halogenated hydrocarbons
d) Chloroquinine
Answer: d
Clarification: Chloroquine and phenothiazines accumulate in skin by interacting with melanin. Since our retinal pigment of eye also has melanin, binding of chloroquine and phenothiazines to it is responsible for retinopathy.

8. Which drugs deposit in hair shafts?
a) Arsenicals
b) Tetracycline
c) Halogenated hydrocarbons
d) Lipophilic drug
Answer: a
Clarification: Arsenicals, chloroquine, phenothiazines are reported to deposit in hair shaft. Tetracycline binds to bones and teeths. Lipophilic drugs accumulate in adipose tissues. Epoxides of number of Halogenated hydrocarbon and paracetamol bind irreversibly to the liver tissues resulting in hepatotoxicity.

9. Which drug causes brown yellow discoloration of infant’s teeth?
a) Arsenicals
b) Tetracycline
c) Halogenated hydrocarbons
d) Lipophilic drug
Answer: b
Clarification: Tetracycline, this drug tends to bind to bones and teeth. Administration of this antibiotic to infants or children during odontogenesis results in permanent brown yellow colour discoloration of teeth.

10. Which drug accumulate in adipose tissue?
a) Arsenicals
b) Tetracycline
c) Halogenated hydrocarbons
d) Lipophilic drug
Answer: d
Clarification: Lipophilic drugs such as that of thiopental and pesticides such as DDT accumulate in adipose tissue. Halogenated hydrocarbon and paracetamol bind irreversibly to the liver tissues resulting in hepatotoxicity. Tetracycline tends to bind to bones and teeth.

11. Which drugs results in distortion of double stranded DNA structure?
a) Arsenicals
b) Quinacrine
c) Halogenated hydrocarbons
d) Lipophilic drug
Answer: b
Clarification: DNA interacts with drugs like Chloroquine and Quinacrine. These drugs result in distortion of the double stranded helical structure of the DNA.

Drug Biotechnology Questions & Answers for Exams on “Non Linearity of Drugs”.

1. Any changes in fraction bioavailable, elimination half-life indicates nonlinearity of that particular drug.
a) True
b) False
Answer: a
Clarification: Some of the pharmacokinetic factors such as fraction bioavailable, elimination half-life or total systemic clearance at different doses of drug normally remains constant. If any changes occur in these constants, this indicates nonlinearity.

2. Which of the following creates nonlinearity in drug distribution and not in drug absorption?
a) When absorption is solubility or dissolution rate-limited
b) When absorption involves carrier-mediated transport systems
c) When a presystemic gut wall or hepatic metabolism attains saturation
d) Saturation of binding sites on plasma proteins
Answer: d
Clarification: Nonlinearity in drug absorption can arise from 3 important sources these are when absorption is solubility or dissolution rate-limited, when absorption involves carrier-mediated transport systems and when presystemic gut wall or hepatic metabolism attains saturation. Nonlinearity in drug distribution occurs when saturation of binding sites on plasma proteins or saturation of tissue binding sites.

3. Which one of these are correct Michaelis-Menten equation?
a) –dC/dt = Vmax C/Km+C
b) dC/dt = Vmax C/Km+C
c) –dC/dt = Vmax C/Km
d) –dC/dt = Km+C/Vmax C
Answer: a
Clarification: The kinetics of capacity-limited or saturation process is described by Michaelis-Menten equation, the equation is –dC/dt = Vmax C/Km+C, where –dC/dt = rate of decline of drug concentration with time, Vmax is the theoretical maximum rate of the process and Km is Michaelis constant.

4. Which equation plot is being shown in the picture?

a) Michaelis-Menten plot
b) One compartment characteristics graph
c) Two compartment characteristics graph
d) Two compartment administered extravascularly characteristics plot
Answer: a
Clarification: The plot is of Michaelis-Menten equation –dC/dt = Vmax C/Km+C, Initially the rate increases linearly with concentration thus showing first order kinetics. It becomes mixed order at higher concentration and then reaches maximum Vmax. Beyond this, it proceeds at a constant rate.

5. In the given picture, which kinetic order the graph is following at the marked place?

a) 1st order kinetics
b) 2nd order kinetics
c) Mixed order kinetics
d) 1st order at higher doses
Answer: a
Clarification: The plot is of Michaelis-Menten equation –dC/dt = Vmax C/Km+C, Initially the rate increases linearly with concentration thus showing first order kinetics. At lower doses, it follows 1st order kinetics. It becomes mixed order at higher concentration and then reaches maximum Vmax. Beyond this, it proceeds at a constant rate thus following zero order kinetics.

6. In the given picture, which kinetic order the graph is following at the marked place?

a) 1st order kinetics
b) 2nd order kinetics
c) Mixed order kinetics
d) 1st order at higher doses
Answer: c
Clarification: The plot is of Michaelis-Menten equation –dC/dt = Vmax C/Km+C, Initially the rate increases linearly with concentration thus showing first order kinetics. It becomes mixed order at intermediate doses and then reaches maximum Vmax. Beyond this, it proceeds at a constant rate.

7. In the given picture, which kinetic order the graph is following at the marked place?

a) 1st order kinetics
b) 2nd order kinetics
c) Mixed order kinetics
d) Zero-order rate
Answer: d
Clarification: The plot is of Michaelis-Menten equation –dC/dt = Vmax C/Km+C, Initially the rate increases linearly with concentration thus showing first order kinetics. At lower doses, it follows 1st order kinetics. It becomes mixed order at intermediate doses and then reaches maximum Vmax. Beyond this, it proceeds at a constant rate thus following zero order kinetics.

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Drug Biotechnology Multiple Choice Questions & Answers on “Pharmacotherapy of Peptic Ulcer – 2”.

1. Which enzyme of H. pyloric helps it to grow in the acidic medium of the stomach?
a) Urease
b) Amylase
c) Protease
d) Acid Hydrolases
Answer: a
Clarification: H. pylori primarily colonize in the antrum of the stomach it resides mainly within the gastric mucus. H. pylori have a high activity of the enzyme urease which enables it to colonize in the stomach. Infection can spread through fecal route. Infection thought to occur between parents and young children.

2. How to diagnose infection by H. pylori?
a) Histology and culture
b) Antibody test
c) Urease CLO test
d) Antibody test, Urease CLO test, Histology and culture
Answer: d
Clarification: The majority of cases of peptic ulcer disease are related to H. pylori. The diagnosis of H. pylori infection must be confirmed prior to initiation of therapy. The methods can be histology and culture, antibody test, urease CLO test. H. pylori have a high activity of the enzyme urease which enables it to colonize in the stomach. Infection can spread through fecal route. Infection thought to occur between parents and young children.

3. Which cells are also known as chief cells?
a) Parietal cells
b) Mucous neck cells
c) Peptic cells
d) Superficial epithelial cells
Answer: c
Clarification: Peptic cells in the stomach lining is also known as a chief cell. The stomach lining has parietal cells that secrete acid, Goblet cells, mucous neck cells, superficial epithelial cells. All these cells can be found in the body and fundus of the stomach.

4. How neuronal regulation of gastric acid is done?
a) Acetylcholine
b) Gastrin
c) Histamine
d) CNS
Answer: a
Clarification: Neuronal control is done by secretion of acetylcholine by the cholinergic neuron. Hormonal control of gastric acid is done by gastrin. Paracrine control of gastric acid is done by histamine secreted by enterochromaffin-like cells.

5. How hormonal regulation of gastric acid is done?
a) Acetylcholine
b) Gastrin
c) Histamine
d) CNS
Answer: b
Clarification: Neuronal control is done by secretion of acetylcholine by the cholinergic neuron. Hormonal control of gastric acid is done by gastrin. Paracrine control of gastric acid is done by histamine secreted by enterochromaffin-like cells.

6. Which will be the correct option for the marked place?

a) Acetylcholine
b) Gastrin
c) Histamine
d) Hydrogen ions
Answer: a
Clarification: Cholinergic neuron secretes acetylcholine that through circulation goes and bind to the muscarinic receptor in the parietal cell secrete acid into the gastric lumen. Enterochromaffin-like cells secrete histamine which again goes and binds to the H2 receptor and through the cAMP pathway helps the parietal cell to secrete acid. Gastrin secreted by Antral G cell is the hormonal control of acid secretion by the parietal cell. Gastrin, Histamine, and acetylcholine switch on the proton pump thus pumping H+ ions to produce acid in the gastric lumen.

7. Which will be the correct option for the marked place?

a) Mucous cells
b) Parietal cells
c) Enterochromaffine like cells
d) Antral G cell
Answer: b
Clarification: Cholinergic neuron secretes acetylcholine that through circulation goes and bind to the muscarinic receptor in the parietal cell secrete acid into the gastric lumen. Enterochromaffine like cells secrete histamine which again go and bind to the H2 receptor and through the cAMP pathway helps the parietal cell to secrete acid.

8. Which will be the correct option for the marked place?

a) Acetylcholine
b) Gastrin
c) Histamine
d) Acid
Answer: d
Clarification: Enterochromaffine like cells secrete histamine which again go and bind to the H2 receptor and through the cAMP pathway helps the parietal cell to secrete acid. Gastrin secreted by Antral G cell is the hormonal control of acid secretion by parietal cell. Acid in our stomach is secreted by the parietal cells. Mucous is secreted by the goblet cells.

9. Which will be the correct option for the marked place?

a) Acetylcholine
b) Gastrin
c) Histamine
d) Hydrogen ions
Answer: b
Clarification: Gastrin secreted by Antral G cell is the hormonal control of acid secretion by parietal cell. Gastrin, Histamine and acetylcholine switch on the proton pump thus pumping H+ ions to produce acid in the gastric lumen. Acid in our stomach is secreted by the parietal cells. Mucous is secreted by the goblet cells.

10. Which will be the correct option for the marked place?

a) Mucous cells
b) Red blood cell
c) Enterochromaffine like cells
d) Antral G cell
Answer: c
Clarification: Enterochromaffine like cells secrete histamine which through circulation again go and bind to the H2 receptor and through the cAMP pathway helps the parietal cell to secrete acid. Gastrin secreted by Antral G cell is the hormonal control of acid secretion by parietal cell.

11. Which will be the correct option for the marked place?

a) Acetylcholine
b) Gastrin
c) Histamine
d) Hydrogen ions
Answer: c
Clarification: Cholinergic neuron secretes acetylcholine that bind to the muscarinic receptor in the parietal cell secrete acid into the gastric lumen. Enterochromaffine like cells secrete histamine which again bind to the H2 receptor and through the cAMP pathway helps the parietal cell to secrete acid. Gastrin secreted by Antral G cell is the hormonal control of acid secretion by parietal cell.

12. Which will be the correct option for the marked place?

a) Mucous cells
b) Red blood cell
c) Enterochromaffine like cells
d) Antral G cell
Answer: d
Clarification: Cholinergic neuron secretes acetylcholine that through circulation goes and bind to the muscarinic receptor in the parietal cell secrete acid into the gastric lumen. Enterochromaffine like cells secrete histamine which again go and bind to the H2 receptor and through the cAMP pathway helps the parietal cell to secrete acid. Gastrin secreted by Antral G cell is the hormonal control of acid secretion by parietal cell. Gastrin, Histamine and acetylcholine switch on the proton pump thus pumping H+ ions to produce acid in the gastric lumen.

13. Inhibition of H⁺, K⁺-ATPase blocks both basal and stimulated acid secretion.
a) True
b) False
Answer: a
Clarification: H⁺, K⁺-ATPase is located in the apical membrane of the oxyntic cell along the secretory canaliculi. The pump requires large amounts of energy that is supplied by intracellular ATP that is why inhibition of H⁺, K⁺-ATPase blocks both basal and stimulated acid secretion.

14. Cimetidine is an H1 receptor antagonist.
a) True
b) False
Answer: b
Clarification: Cimetidine is an H2 receptor antagonist thus used in the treatment of peptic ulcer. It inhibits basal acid secretion of the stomach including nocturnal secretion. It is readily absorbed after oral administration and has a brief duration of action from 4-8 hr.

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Drug Biotechnology Multiple Choice Questions on “Mechanisms of Drug Absorption”.

1. Which is the major process of absorption for more than 90% of drugs?
a) Facilitated diffusion
b) Active transport
c) Endocytosis
d) Passive diffusion
Answer: d
Clarification: Passive diffusion is also known as non-ionic diffusion. It is the major process through which 90% of the drugs get absorbed. The driving force for passive diffusion is the concentration gradient and electrochemical gradient.

2. What is the driving force for Passive Diffusion?
a) Concentration gradient only
b) Electrochemical gradient only
c) Charge equilibration and concentration gradient
d) Concentration and Electrochemical gradient both
Answer: d
Clarification: Passive diffusion, the driving forces are both concentration gradient and electrochemical gradient. According to Fick’s first law of diffusion, drug molecules always diffuse from the site of higher concentration to the site of lower concentration until equilibrium is attained.

3. Which kind of molecules cannot pass through a pore transport?
a) Low Molecular weight molecules
b) Water-soluble drugs
c) Molecules up to 400 Dalton
d) Molecules greater than 400 Dalton
Answer: d
Clarification: Pore transport is important for the absorption of low molecular weight and size molecules. Water-soluble drugs can also easily pass through the aqueous filled spaces or pores in the cell membrane. Linear molecules of size up to 400 Dalton can be absorbed.

4. What is the driving force of Pore Transport?
a) Hydrostatic pressure
b) Concertation Gradient
c) Electrochemical gradient
d) Charge equilibration
Answer: a
Clarification: The driving force of pore transport is Hydrostatic pressure and Osmotic pressure across the cell membrane. Electrochemical gradient and concentration gradient is the driving force of passive diffusion.

5. What will be the best definition for “carrier”?
a) Nonpolar drugs can be transported through carrier-mediated transport
b) Carrier binds reversibly and no covalently with the molecules
c) It discharges the molecules and gets destroyed itself
d) The carrier is a protein
Answer: b
Clarification: The carrier-solute complex can cross the membrane to reach the other site where the carrier discharges the solute and returns back to its position. The carriers carry polar charged molecules and are mostly enzymes.

6. What is the major difference between Facilitated diffusion and Passive diffusion?
a) Carrier-mediated transport
b) Downhill transport
c) Energy is used
d) Inhibition by metabolic poisons
Answer: a
Clarification: Facilitated diffusion is a carrier-mediated transport which operates down the concentration gradient. It is faster than passive diffusion because of the involvement of Carriers. The driving force is the concentration gradient.

7. What influences the permeation of drugs in an Ionic or Electrochemical diffusion?
a) Charge on the membrane
b) Charge on the particle
c) Concentration gradient
d) Equilibration of charge
Answer: a
Clarification: The charge on the membrane influences the permeation of drugs. The permeation of positively charged drugs depends on the potential difference or electrical gradient as the driving force across the membrane.

8. Which kind of drugs are absorbed through endocytosis?
a) Molecular weight ranging 100-400Dalton
b) Water-soluble drugs
c) Macromolecular drugs or drugs as oily droplets
d) Polar drugs
Answer: c
Clarification: Macromolecular drugs, Drugs as solid particles and drugs as oily particles are absorbed through endocytosis. Passive diffusion helps in the absorption of drugs with molecular size fro 100-400 Dalton.

9. Which drugs are absorbed through pore transport?
a) High lipophilicity
b) Water-soluble drugs of molecular weight less than 100 Dalton
c) Oily droplets
d) Affinity for carriers
Answer: b
Clarification: Pore transport helps in the transport of water-soluble drugs which are of molecular weight less than 100 Dalton. Drugs with high lipophilicity and a molecular weight between 100-400 Dalton are transported by Passive diffusion.

10. Which types of drugs get absorbed by ion-pair transport?
a) High lipophilicity
b) Oily droplets
c) Affinity for carriers
d) Drugs that ionize at all pH conditions
Answer: d
Clarification: Ion-Pair Transport is the mechanism where absorption of drugs like quaternary ammonium compounds, sulphonic acids get absorbed. These drugs can get ionize at all pH conditions. These neutral complexes have lipophilicity and aqueous solubility for passive diffusion.

11. Which of these absorption methods involves engulfing of the extracellular drug?
a) Endocytosis
b) Passive diffusion
c) Facilitated diffusion
d) Ion-Pair transport
Answer: a
Clarification: Endocytosis is the absorption method which includes engulfing of extracellular materials within a segment of the cell membrane to form a saccule or vesicle which will be then pinched off intracellularly.

12. Which is the other name of “cell eating”?
a) Transcytosis
b) Phagocytosis
c) Pinocytosis
d) Endocytosis
Answer: b
Clarification: Phagocytosis is a type of endocytosis. Phagocytosis is also called cell eating which includes absorption of solid particulates. Endocytosis is of two types phagocytosis and pinocytosis later meaning cell drinking.

13. Transfer of an endocytic vesicle from one extracellular compartment to another is known as _____________
a) Phagocytosis
b) Transcytosis
c) Pinocytosis
d) Endocytosis
Answer: b
Clarification: Transfer of an endocytic vesicle from one extracellular compartment to another is known as Transcytosis. Phagocytosis is the engulfing of solid particulates. Pinocytosis is the absorption of fluids.

14. A drug can be absorbed by more than one mechanism.
a) True
b) False
Answer: a
Clarification: Yes, a drug can be absorbed by different mechanisms through different sites in the body. The mechanism depends upon the absorption site of the body. A drug can be absorbed passively and actively.

15. Which kind of absorption mechanism is showing in the following picture?

a) Endocytosis
b) Passive transport
c) Active transport
d) Facilitated diffusion
Answer: b
Clarification: Passive diffusion is a kind absorption where substances move from higher concentration to the lower concentration without the use of any carriers or energy. 90% of the drugs are absorbed through Passive diffusion.

Drug Biotechnology written test Questions & Answers on “Factors Affecting Protein Drug Binding”.

1. Which one of the following factors related to protein-drug binding is not related to drugs?
a) Physicochemical characteristics of a drug
b) The concentration of the drug in the body
c) The affinity of the drug for binding
d) Number of binding sites on the binding agent
Answer: d
Clarification: There are many factors affecting protein-drug binding. The factors related to the drug, are physicochemical characteristics of a drug, concentration of the drug in the body, affinity of the drug for binding. A number of binding sites on the binding agent are related to the protein and other binding components.

2. Which one of the following factor related to protein-drug binding is not related to drug interactions with the binding site?
a) Competition between the drug and the binding site
b) Competition between drugs and normal body constituents
c) Allosteric changes in a protein molecule
d) Inter subject variation
Answer: d
Clarification: Competition between the drug and the binding site, competition between drugs and normal body constituents, allosteric changes in protein molecule these factors are related to drug interactions. Inter subject variation is a patient-related factor.

3. Which of the following factors for protein drug binding is a drug interaction factor?
a) Competition between drugs for the binding site
b) Age
c) Physicochemical characteristics of a drug
d) Physicochemical characteristics of the protein or binding agent
Answer: a
Clarification: Physicochemical interaction is not a drug interaction factor. Competition between the drug and the binding site and competition between drug and other normal body constituents, allosteric changes in protein molecule all these factors are related to drug interaction with the protein. Age is a patient-related factor.

4. Which drugs bind to HSA easily?
a) Cationic drug
b) Anionic drug
c) Lipophilic drug
d) Neutral drug
Answer: b
Clarification: Anionic or acidic drugs bind to HSA easily, for example, penicillin and sulphonamides. Cationic or basic drugs bind easily to alpha 1 acid glycoprotein, for example, imipramine and alprenolol. Neutral and unionized drugs bind to lipoproteins. Lipophilic drugs localize more into adipose tissue.

5. Which drugs easily bind to adipose tissue?
a) Cationic drug
b) Anionic drug
c) Lipophilic drug
d) Neutral drug
Answer: c
Clarification: Anionic or acidic drugs bind to HSA easily. Cationic or basic drugs bind easily to alpha 1 acid glycoprotein. Neutral and unionized drugs bind to lipoproteins. Lipophilic drugs localize more into adipose tissue. Since lipophilic drugs are lipid loving they can easily get deposited on the adipose tissue.

6. Which drug easily bind to AAG?
a) Cationic drug
b) Anionic drug
c) Lipophilic drug
d) Neutral drug
Answer: a
Clarification: Anionic or acidic drugs bind to HSA easily. Cationic or basic drugs having negative charge can bind easily to alpha 1 acid glycoprotein, for example, imipramine and alprenolol. Neutral and unionized drugs bind to lipoproteins. Lipophilic drugs localize more into adipose tissue.

7. The extent of drug-protein binding can change with both changes in protein and drug concentration.
a) True
b) False
Answer: a
Clarification: The concentration of drug that binds to HSA do not have much influence on HA, since any concentration of drug in less than the concentration of HSA. The therapeutic concentration of lidocaine can saturate AAG with which it binds as the concentration of AAG is much less in comparison to that of HSA in blood.

8. In the equation X= Vd C, what does X stands for?
a) Amount of drug in the blood
b) Amount of drug in plasma
c) Amount of drug in the tablet
d) Amount of drug in the body
Answer: d
Clarification: The relationship between tissue-drug binding and apparent volume of distribution can be established as Vd = amount of drug in the body (X)/ Plasma drug concentration (C).

9. Only unbound or free drug is capable of being eliminated.
a) True
b) False
Answer: a
Clarification: Unbound or free drug is capable of being eliminated. Because the drug-protein complex cannot penetrate into the metabolizing organ. The large molecular size of the complex also prevents it from getting filtered through the glomerulus.

10. Penicillin has short plasma half-life although it can bind to plasma protein rigidly.
a) True
b) False
Answer: a
Clarification: Penicillin has a short plasma half-life. Though it can rigidly bind to the plasma still it has short elimination half live. This is because equilibration occurs between the free and the bound protein and the free drug is equally rapidly excreted by active secretion in renal tubules.

11. What kind of graph is shown in the picture?

a) Direct plot
b) Scatchard plot
c) Double reciprocal plot
d) Michele’s menten plot
Answer: a
Clarification: The graph which is got by potting r v/s D then we call it a direct plot. When all the binding sites are occupied by the drug, the protein is saturated and plateau is reached. At the plateau r=N.

12. What kind of graph is shown in the picture?

a) Direct plot
b) Scatchard plot
c) Double reciprocal plot
d) Michele’s menten plot
Answer: b
Clarification: The plot between r/d v/s r is known as Scatchard plot. This plot is a straight line. The slope of the line –Ka, Y intercept is NKa and X intercept is N.

13. What kind of graph is shown in the picture?

a) Direct plot
b) Scatchard plot
c) Double reciprocal plot
d) Michele’s menten plot
Answer: c
Clarification: Double reciprocal plot is also known as Lineweaver Burk plot. This plot of 1/r versus 1/D yields a straight line with slope 1/NKa and Y-intercept 1/N.

14. Displacement interactions are significant in the case of drugs which are more than 95% bound.
a) True
b) False
Answer: a
Clarification: A displacement of 1% and 99% bound drug results in doubling of the free drug concentration i.e. a 100% rise. For a drug which is bound to 99% and a displacement of 1% results in only a 10% rise in freed rug concentration which may be insignificant clinically.

15. Which of the following is a correct method to find the fraction of unbound drug in plasma? Given where Cu is the concentration of unbound drug and C is total plasma drug concentration.
a) CuC
b) C / Cu
c) Cu/C
d) 1/C Cu
Answer: c
Clarification: The fraction of unbound drug can be calculated with the formula fu = Cu/C, where Cu is the concentration of unbound drug and C is total plasma drug concentration and fu is the unbound drug.

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