I Cell; Transport across membrane; Membrane potentials
1. Membrane fluidity is increased by
a. Stearic acid
b. Cholesterol
c. Linoleic acid
d. Palmitic acid
Ans. C Unsaturated fatty acid increases fluidity of cell membrane
2. Fick’s law of diffusion explains
a. Active diffusion along concentration gradient
b. Passive diffusion along concentration gradient
c. Both
d. None
Ans. B Facilitated diffusion does not require energy
3. All of the following are true except
a. Facilitated diffusion requires energy
b. Active transport is an energy dependent process
c. Co-transport is mediated via carriers
d. Glucose is transported via passive diffusion
Ans. A Facilitated diffusion does not require energy only carriers.
4. Initiation of nerve impulse occurs at axon hillock because
a. It has a lower threshold than the rest of the axon
b. It is unmyelinated
c. Neurotransmitter release occurs here
d. None
Ans. A High density of sodium ion channels in the axon hillock causes a low threshold for the initiation of
action potential.
5. Resting membrane of neuron is close to the ionic potential of
a. Na+ b. Cl- c. K+ d. Mg2+
Ans. C The membrane is more permeable to K+
II NMJ; Muscle physiology
1. Spontaneous release of Ach at NMJ produces
a. Miniature endplate potentials
b. Action potential
c. Post-tetanic potential
d. Resting membrane potential
Ans. A Only a few channels open causing a small influx of sodium ions resulting in a miniature end plate
potentials
2. Release of synaptic vesicle from pre-synaptic terminal is inhibited by
a. Preventing depolarization of nerve terminal
b. Inhibiting impulse conduction
c. Prevention of calcium ion influx
d. Prevention of sodium ion influx
Ans. C Potential difference at pre synapse causes opening of calcium channels that help binding of vesicles.
3. Myasthenia gravis is a disorder of
a. Motor neuron
b. NMJ
c. Spinal cord
d. Peripheral neuron
Ans. B Antibodies against Ach receptors at NMJ are produced in Myasthenia gravis
4. In muscle contraction, all are true EXCEPT
a. A band remains unchanged
b. H zone disappears
c. I band becomes wider
d. Two Z lines come closer
Ans. C I bands contract so cannot become wider
5. Which of the following triggers muscle contraction?
a. Calcium binding tropomyosin
b. Calcium binding troponin C
c. ATP breakdown
d. Calcium binding troponin I
Ans. B Troponin I and T undergo conformational change and moves tropomyosin exposing the
active sites
III Functions of components of blood
1. Albumin is an important factor in maintaining osmotic pressure because it has
a. Low molecular weight and high blood concentration
b. Low molecular weight and low blood concentration
c. High molecular weight and low blood concentration
d. High molecular weight and high blood concentration
Ans. A More in number with a decreased molecular weight compared to the other proteins
2. The type of hemoglobin that has least affinity for 2,3-DPG
a. HbA
b. HbF
c. HbA2
d. Hb
Ans. B HbF has no receptors for 2,3-DPG
3. Memory cells in immune system are long lived and escape apoptosis because of
a. Insulin-like Growth Factor
b. Fibroblast Growth Factor
c. Platelet derived Growth Factor
d. Nerve Growth Factor
Ans. D NGF inhibits apoptosis in memory cells
4. Erythropoiesis is promoted by all of these except
a. Thyroxine
b. ACTH
c. Testosterone
d. Oestrogen
Ans. D Oestrogen inhibits erythropoietin
5. All are functions of platelets EXCEPT
a. Adhere to exposed endothelium
b. Clot retraction
c. Convert Fibrinogen to Fibrin
d. Vasdoconstriction Ans. C Thrombin converts fibrinogen to fibrin
IV Hemostasis; Blood grouping
1. The blood within the vessels do not clot normally because
a. Vitamin K antagonists are present in plasma
b. Thrombin has positive feedback on Plasminogen
c. Vascular endothelium is smooth and coated with glycocalyx
d. Sodium citrate in plasma chelates calcium ion
Ans. C Smoothness and glycocalyx layer prevents adherence of platelets
2. All are Vit K dependent clotting factors of hepatic origin EXCEPT
a. II
b. VII
c. VIII
d. X
Ans. C factor VIII does not require Vit K for its synthesis
3. Which of the following is not involved in intrinsic pathway?
a. Factor XII
b. Factor VII
c. Factor IX
d. Factor XI
Ans. B Factor VII is involved in extrinsic pathway
4. All of these are true about Haemophilia A EXCEPT
a. PTT is increased
b. Clotting time is increased
c. PT is increased
d. Serum levels of factor VIII decreased
Ans. C PT measures Factors I, II, V, VII, X
5. ABO blood group still remains important in clinical medicine even after the discovery of many
blood groups because
a. It was first discovered
b. Comprises of 4 different blood groups
c. ABO antibodies are present in the plasma when a person’s RBC lacks corresponding antigen
d. ABO antigens are present in most body tissues and fluids
Ans. C The presence of antibodies in the plasma even in the absence of an antigen can cause complications in
case of mismatch transfusions
