MCQ Flashcards
(64 cards)
Which of the following types of receptors elicit the quickest response? A. Ligand gated ion channels B. G-protein coupled receptors C. Tyrosine kinase receptors D. Nuclear receptors E. None of the above
A. Ligand gated ion channels
Which of following terms describes a drug that binds to a receptor but does not elicit a response? A. Agonist B. Antagonist C. A competitive inhibitor D. A non-competitive inhibitor E. Partial agonist
B. Antagonist
Which of the following types of receptors describes the insulin receptor and ligand binding to its receptor initiates a phosphorylation cascade? A. A ligand-gated ion channel B. A G-protein-coupled receptor C. A Tyrosine kinase receptors D. A nuclear receptor E. A G-protein system
C. A Tyrosine kinase receptors
Which part of the membrane-bound receptors is hydrophobic? A. Extracellular N-terminus B. Intracellular C-terminus C. Transmembrane domain D. Ligand binding domain E. All the above are hydrophobic
C. Transmembrane domain
Which of the following statements is not true about ligand gated ion channels?
A. Each receptor consists of 4-5 membrane spanning domains
B. Excitatory neurotransmitters such as acetylcholine, and glutamate induce opening of cation channels
C. Include both a binding site for a neurotransmitter and an ion-conducting pore
D. The five M2 helices that form the pore are sharply kinked inward halfway through the membrane forming a constriction
E. Inhibitory neurotransmitters such as GABA induce opening of anion channels
A. Each receptor consists of 4-5 membrane spanning domains
Which of the following statements is INCORRECT about G-protein coupled receptors?
A. Are called 7-transmembrane receptors
B. The long third cytoplasmic loop is responsible for coupling to G protein system
C. Are made of α-β-ϒ subunits
D. Activation of these receptors results in activation/inhibition of adenylate cyclase/cAMP second messenger pathway
E. Activation of these receptors sometimes results in increase in intracellular Ca2+ levels
C. Are made of α-β-ϒ subunits
The G-protein system :
A. Is located on the outside of the plasma membrane
B. Is called G-protein because of its interaction with cAMP
C. Is made up of alpha-beta subunits only
D. Exists as a trimer in the resting state
E. Is made up of 7 transmembrane domains
D. Exists as a trimer in the resting state
With respect to G-proteins decide which of the following statements is CORRECT?
A. A GTP molecule is bound to G-protein in the resting state
B. The G-protein is activated by binding of GDP
C. The GTP molecule binds to the alpha subunit
D. Binding of the GDP activates the G-protein
E. The GDP molecule binds to the B-ƴ subunits
C. The GTP molecule binds to the alpha subunit
In regards to the adenylate cyclase/ cAMP system which of the following statements is true?
A. Adenylate cyclases are intrinsic proteins of the plasma membrane activated by Gs-coupled receptors
B. Cyclic adenosine monophosphate (cAMP) is a nucleotide synthesised within the cell from ATP by adenylate cyclase
C. cAMP is inactivated by hydrolysis to 5’-AMP by the action of a family of enzymes known as phosphodiesterases (PDEs).
D. cAMP activates other proteins within the cell such as protein kinases
E. All of the above are true
E. All of the above are true
Activation of phospholipase C/inositol system results in?
A. Activation of protein kinases through cAMP
B. Generation of PIP2 through activation of adenylate cyclase
C. Increase in intracellular Ca+2 levels
D. Binding of DAG to ligand-gated ion channels expressed on endoplasmic reticulum
E. None of the above
C. Increase in intracellular Ca+2 levels
A drug with a pKa value of 3.5 can:
A. Get trapped in the alkaline urine
B. Get trapped in the acidic gastric juice
C. be eliminated by acidifying the urine
D. be eliminated by neutralizing urine’s pH
E. Be distributed equally between the plamsa, gastric juice and alkaline urine.
A. Get trapped in the alkaline urine
Using the concentration/time curve for drug x which has been administered intravenously, which letter represents the time of onset of action for the drug?
A. A
Which statement about intravenous administration of anaesthetics is accurate?
A. Allows the administration of fluids indirectly into the bloodstream.
B. By-passes the ‘first-pass’ effect of liver and digestive enzymes.
C. Allows slow release of drugs into the bloodstream.
D. The peak concentration reaching the tissue depending on the angle and site of injection.
E. The response to intravenous administration depends on the amount of food in the stomach.
B. By-passes the ‘first-pass’ effect of liver and digestive enzymes.
Which of the following factors affect the absorption of a drug from the GI tract? A. Gastrointestinal motility B. Splanchic blood flow C. Particle size and formulation D. Physiochemical factors E. All the above
E. All the above A. Gastrointestinal motility B. Splanchic blood flow C. Particle size and formulation D. Physiochemical factors
Drug A has a volume of distribution (Vd) of around 5 litres and an drug B has a Vd of around 100 litres, which of the following statements about the distribution of these two drugs in the body is CORRECT?
A. Drug A is tightly bound to plasma proteins and drug B is tightly bound to tissue components.
B. Drug A is tightly bound to tissue components and drug B is tightly bound to plasma proteins.
C. Both drugs are tightly bound to tissue proteins.
D. Both drugs are tightly bound to tissue components
E. Drug distribution cannot be determined using their Vd values.
A. Drug A is tightly bound to plasma proteins and drug B is tightly bound to tissue components.
Which of the following statements about renal excretion of drugs is CORRECT?
A. Total excretion= glomerular filtration+ reabsorption-tubular secretion
B. Glomerular secretion is important for removal of protein bound drugs
C. The pH partition between plasma and urine determine the rate of tubular secretion
D. Tubular secretion the most effective mechanism of renal drug elimination
E. All the above are correct
D. Tubular secretion the most effective mechanism of renal drug elimination
Activation of which receptor results in the quickest response?
A. Nicotinic receptor
B. Insulin-like growth factor receptor
C. Muscarinic M3 receptor
D. Oestrogen receptor
E. All the above have a similar response time.
A. Nicotinic receptor
Which of the following group of drugs uses synthetic oligonucleotides to target mRNA? A. DNA intercalators B. Alkylating agents C. Chain cutters D. Antisense drugs E. None of the above
D. Antisense drugs
If the alpha subunit of a G-protein system is Gαi, activation of the receptor associated with this system results in:
A. increase in intracellular Ca+2 levels.
B. decrease in intracellular Ca+2 levels.
C. increase in intracellular cAMP levels.
D. decrease in intracellular cAMP levels.
E. activation of potassium channels.
D. decrease in intracellular cAMP levels.
Drugs administered via the parenteral route are absorbed relatively rapidly. Which of the following is the correct order of drug absorption for medicines administered via this route? A. IV > SC > IM B. SC > IV > IM C. IV > IM > SC D. IM > IV > SC E. IM > SC > IV
C. IV > IM > SC
Which of the following is NOT a parental route of drug administration? A. Intravenous B. Intramembranous C. Intramuscular D. Intradermal E. Subcutaneous
B. Intramembranous
"The time taken for the concentration of a drug to fall by half its original value" relates to: A. Bioavailability B. EC50 C. Half life D. Potency E. TC50
C. Half-life
The study of the way in which drugs interact with receptors in the body is termed.. A. receptors. B. pharmacodynamics. C. pharmacology. D. biochemistry. E. pharmacogenetics.
B. pharmacodynamics.
Which of the following is not a consideration for a Phase 2 clinical trial? A. Multicentre B. Healthy volunteers C. Multi-arm D. Blinded test E. Large sample (hundreds)
B. Healthy volunteers