Fundamentals Tutorial Week 3

Pregunta	Respuesta
Concerning drug receptor interaction, the constant Kd refers to: a. Maximal physiological effect b. Maximal drug binding to the receptor c. Drug concentration required to occupy 50% of receptors d. Drug concentration that results in half-maximal physiological response	Drug concentration required to occupy 50% of receptors
G protein-coupled receptors are characterised by: a. Linkage to ion channels b. Intracellular tyrosine kinase activity c. 7 transmembrane domains d. Their intracellular location	a. Incorrect, this not one of GPCR characteristics b. Incorrect, those are Tyrosine kinase-linked receptors c. Correct! d. Incorrect, those are intracellular receptors
Which of these is NOT an effect that follows receptor activation? a. Increase in intracellular cAMP levels b. Increase in intracellular calcium levels c. Increase in intracellular IP3 levels d. Increase in intracellular ATP levels	a. Incorrect this could be a result of GPCR activation b. Incorrect this could be a result of GPCR activation c. Incorrect this could be a result of GPCR activation d. Correct, ATP increases through metabolism!
Which statement is TRUE regarding competitive receptor antagonism? a. Competitive antagonism is based on reversible antagonist binding at the receptor active site b. With competitive inhibition, the dose-effects curve is shifted to the left c. With competitive inhibition, maximum drug effect cannot be obtained, even at high agonist concentrations d. With competitive antagonism, maximal drug effect is lower	A) Competitive antagonism is based on reversible antagonist binding at the receptor active site
How is GABA channel changing nerve membrane polarity? a. It causes depolarisation b. It increases polarisation c. It does not change membrane polarity d. It increases existing depolarisation event	a. Incorrect. Na+ channels do that b. Correct, through increasing negative charge inside the nerve! c. Incorrect, change in membrane polarity is the main function of GABA channel d. Incorrect, it works against depolarisation caused by Na+ channels
Which drug exerts much of its effects through intracellular receptors? a. Phenytoin b. Diazepam c. Fluticasone d. Flumazenil	a. Incorrect, phenytoin is a Na+ channel blocker b. Incorrect, diazepam is a GABA channel activator c. Correct, fluticasone it is a steroid! d. Incorrect, flumazenil it is a benzodiazepine antagonist
Which of the following statements is NOT TRUE regarding the binding site of a receptor? a. The binding site is normally a hollow or cleft in the surface of a receptor b. The binding site is normally hydrophobic in nature c. Ligands fit into binding sites and bind to the functional groups within the binding site d. Receptor binding site contains amino acids which are important to the binding process	a. Incorrect, that statement is true b. Correct, binding sites are not always hydrophobic! c. Incorrect, that statement is true d. Incorrect, that statement is true
Which of the following reactions is catalyzed by a protein kinase? a. Phosphorylation of alcohol groups in protein substrates b. Hydrolysis of phosphate groups in protein substrates c. Phosphorylation of alcohol groups in carbohydrates d. Hydrolysis of phosphate groups in ATP and GTP	A) -OH group gets phosphorylated!
What determines the degree of movement of a drug between body compartments? a. Charge of the drug b. pH within the compartment c. Size of the drug molecule d. All of the above	d) all of the above
Which of the following describes drug minimal effective concentration (MEC)? a. The minimal drug plasma concentration that can be detected b. The minimal drug plasma concentration to enter tissues c. The minimal drug plasma concentration to interact with receptors d. The minimal drug plasma concentration to produce effect	D) the MEC is the minimal drug plasma concentration to produce effect
Which of the following indicates amount of a drug absorbed per amount administered? a. Bioavailability b. Drug elimination c. Drug absorption d. Dosage	bioavailability
Bioavailability is percentage of administered drug that reaches the systemic circulation via a given route as compared to what route?	IV
Given a graph of plasma drug concentration versus time, what part of the graph would be used to calculate bioavailability for an oral drug administration? a. Maximum concentration b. Slope of the curve c. Integral of the curve (area underneath) d. The curve is not used to calculate bioavailabilit	C) AUC
Drug biotransformation phase I makes drugs ____ polar for metabolism and phase II makes drugs ____ polar for excretion	Drug biotransformation phase I makes drugs MORE polar for metabolism and phase II makes drugs MORE polar for excretion
Which of the following is NOT a phase II substrate? a. Glucuronic acid b. Sulphate c. Acetate d. Alcohol	d) alcohol
What is the correct order of bond strength, from strongest to weakest?	Covalent > Ionic > Hydrogen > Van der Waals
Which of the following is the equilibrium dissociation constant, where the concentration of free drug is at half-maximal binding? a. EC50 b. Emax c. Kd d. Bmax	Kd
Which of the following is increased in intracellular concentration due to second messenger IP3? a. K+ b. Ca++ c. Cl- d. Na+	b. Ca++
Which direction would a PARTIAL agonist shift the dose-response curve when compared to a full agonist? a. To the left b. To the right c. Down d. Up	c) down
Which of the following is NOT an action of the body on a drug? a. Absorption b. Distribution c. Metabolism e. Drug side effects	D - side effects

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