51. All are derivatives of neural crest EXCEPT
A. Schwann cells
B. Dorsal root ganglion
C. Adrenal cortex
D. Melanocytes
Ans C
Neural Crest derivatives
Neural crest cells are a transient, multipotent, migratory cell population unique to vertebrates that gives rise to a diverse cell lineage including melanocytes, craniofacial cartilage and bone, smooth muscle, peripheral and enteric neurons and glia
Mesectoderm: odontoblasts, dental papillae, the chondrocranium (nasal capsule, Meckel's cartilage, scleral ossicles, quadrate, articular, hyoid and columella), tracheal and laryngeal cartilage, the dermatocranium (membranous bones), dorsal fins and the turtle plastron (lower vertebrates), pericytes and smooth muscle of branchial arteries and veins, tendons of ocular and masticatory muscles, connective tissue of head and neck glands (pituitary, salivary, lachrymal, thymus, thyroid) dermis and adipose tissue of calvaria, ventral neck and face
Endocrine Cells: chromaffin cells of the adrenal medulla, parafollicular cells of the thyroid, glomus cells type I/II
Peripheral nervous system: Sensory neurons and glia of the dorsal root ganglia, cephalic ganglia (VII and in part, V, IX, and X), Rohon-Beard cells, some Merkel cells in the whisker Satellite glial cells of all autonomic and sensory ganglia, Schwann cells of all peripheral nerves
52. Branches of lumbar plexus which emerge from anterior surface of psoas major muscle is
A. iliohypogastric nerve
B. ilioinguinal nerve
C. genitofemoral nerve
D. obturator nerve
Ans C
Branches:
The small motor branches of the plexus are distributed directly to the psoas major muscle. The large motor branches leave the muscle along its lateral and medial borders and along the anterior surface. Consequently, they are categorized as follows;
Branches leaving the lateral border of psoas:
These include the following branches (in order from above downward)
• Iliohypogastric nerve: It supplies the skin of lower part of anterior abdominal wall.
• Ilioinguinal nerve: It passes through the inguinal canal to supply the skin of groin and scrotum (in males) or labium majus (in females).
• Lateral cutaneous nerve of thigh: It crosses the iliac fossa in front of the iliacus muscle and enters the lateral aspect of thigh behind the lateral end of inguinal ligament. It supplies the skin over the lateral surface of thigh.
• Femoral nerve: It is the largest branch of lumbar plexus. It enters the thigh lateral to the femoral sheath and supplies various muscles. In the abdomen, it supplies the iliacus muscle.
Branches leaving the medial border of psoas:
• Obturator nerve: It crosses the pelvic brim in front of the sacroiliac joint and then leaves the pelvis by passing into the thigh through the obturator foramen.
• Fourth lumbar root of lumbosacral trunk: It emerges from the medial border of the psoas at the pelvic brim. It takes part in the formation of sacral plexus.
Branches leaving the anterior surface of psoas:
Genitofemoral nerve: After emerging from the anterior surface of the muscle, it runs down in front of it and divides into a genital branch and a femoral branch. The former supplies the cremaster muscle and the latter supplies a small area of skin of thigh.
53. Round window (fenestra cochlea) of middle ear is closed by
A. foot plate of stapes
B. secondary tympanic membrane
C. vestibular membrane
D. foot plate of incus
Ans b
The round window is one of the two openings into the inner ear. It is closed off from the middle ear by the round window membrane, which vibrates with opposite phase to vibrations entering the inner ear through the oval window. It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
The secondary tympanic membrane (or round window membrane) covers the round window, sealing off one of two openings into the inner ear. It separates the scala tympani of the cochlea from the middle ear. It vibrates with opposite phase to vibrations entering the cochlea through the oval window as the fluid in the cochlea is displaced when pressed by the stapes at the oval window. This ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
54. Portal vein formation lies
A. behind the second part of duodenum
B. posterior to the neck of the pancreas ,r
C. posterior to the body of the pancreas
D. posterior to the tail of the pancreas
Ans b
The pancreas, an exocrine and endocrine gland, has a head, neck, body, and tail. The portal vein is formed posterior to the neck of the pancreas by the union of the superior mesenteric and splenic veins.
55. The knee joint is supported by all the following ligaments, EXCEPT
A. Anterior cruciate ligament
B. Inverted Y-shaped ligament of Bigelow
C. Oblique popliteal ligament
D. Fibular collateral ligament
Ans B
The iliofemoral ligament is a ligament of the hip joint which extends from the ilium to the femur in front of the joint. It is also referred to as the Y-ligament (see below) or the ligament of Bigelow, and any combinations of these names.
With a tensile strength exceeding 350 kg (772 lbs),[1] the iliofemoral ligament is not only stronger than the two other ligaments of the hip joint, the ischiofemoral and the pubofemoral, but also the strongest ligament in the human body and as such is an important constraint to the hip joint
56. Stimulation of J receptors causes all of the following EXCEPT
A. Bradycardia
B. Hypotension
C. Hypertension
D. Rapid breathing
Ans C
J-receptors (juxtacapillary) are nerves innervating into the body of the lung. They are present in the alveolar interstitium and are innervated by fibers of the vagus nerve.[1] J-receptors respond to events such as pulmonary edema, pulmonary emboli, pneumonia, congestive heart failure and barotrauma, which cause a decrease in oxygenation and thus lead to an increase in ventilation/respiration. They may be also stimulated by hyperinflation of the lung as well as intravenous or intracardiac administration of chemicals.
The stimulation of the J-receptors causes a reflex increase in breathing rate, and is also thought to be involved in the sensation of dyspnea, the subjective sensation of difficulty breathing. [2][3] The reflex response that is produced is apnea followed by rapid breathing, bradycardia, and hypotension (pulmonary chemoreflex). The physiologic role of this reflex is uncertain, but it probably occurs in pathologic states such as pulmonary congestion or embolization.[4] These receptors were discovered by Dr. A.S Paintal
B. Dorsal root ganglion
C. Adrenal cortex
D. Melanocytes
Ans C
Neural Crest derivatives
Neural crest cells are a transient, multipotent, migratory cell population unique to vertebrates that gives rise to a diverse cell lineage including melanocytes, craniofacial cartilage and bone, smooth muscle, peripheral and enteric neurons and glia
Mesectoderm: odontoblasts, dental papillae, the chondrocranium (nasal capsule, Meckel's cartilage, scleral ossicles, quadrate, articular, hyoid and columella), tracheal and laryngeal cartilage, the dermatocranium (membranous bones), dorsal fins and the turtle plastron (lower vertebrates), pericytes and smooth muscle of branchial arteries and veins, tendons of ocular and masticatory muscles, connective tissue of head and neck glands (pituitary, salivary, lachrymal, thymus, thyroid) dermis and adipose tissue of calvaria, ventral neck and face
Endocrine Cells: chromaffin cells of the adrenal medulla, parafollicular cells of the thyroid, glomus cells type I/II
Peripheral nervous system: Sensory neurons and glia of the dorsal root ganglia, cephalic ganglia (VII and in part, V, IX, and X), Rohon-Beard cells, some Merkel cells in the whisker Satellite glial cells of all autonomic and sensory ganglia, Schwann cells of all peripheral nerves
52. Branches of lumbar plexus which emerge from anterior surface of psoas major muscle is
A. iliohypogastric nerve
B. ilioinguinal nerve
C. genitofemoral nerve
D. obturator nerve
Ans C
Branches:
The small motor branches of the plexus are distributed directly to the psoas major muscle. The large motor branches leave the muscle along its lateral and medial borders and along the anterior surface. Consequently, they are categorized as follows;
Branches leaving the lateral border of psoas:
These include the following branches (in order from above downward)
• Iliohypogastric nerve: It supplies the skin of lower part of anterior abdominal wall.
• Ilioinguinal nerve: It passes through the inguinal canal to supply the skin of groin and scrotum (in males) or labium majus (in females).
• Lateral cutaneous nerve of thigh: It crosses the iliac fossa in front of the iliacus muscle and enters the lateral aspect of thigh behind the lateral end of inguinal ligament. It supplies the skin over the lateral surface of thigh.
• Femoral nerve: It is the largest branch of lumbar plexus. It enters the thigh lateral to the femoral sheath and supplies various muscles. In the abdomen, it supplies the iliacus muscle.
Branches leaving the medial border of psoas:
• Obturator nerve: It crosses the pelvic brim in front of the sacroiliac joint and then leaves the pelvis by passing into the thigh through the obturator foramen.
• Fourth lumbar root of lumbosacral trunk: It emerges from the medial border of the psoas at the pelvic brim. It takes part in the formation of sacral plexus.
Branches leaving the anterior surface of psoas:
Genitofemoral nerve: After emerging from the anterior surface of the muscle, it runs down in front of it and divides into a genital branch and a femoral branch. The former supplies the cremaster muscle and the latter supplies a small area of skin of thigh.
53. Round window (fenestra cochlea) of middle ear is closed by
A. foot plate of stapes
B. secondary tympanic membrane
C. vestibular membrane
D. foot plate of incus
Ans b
The round window is one of the two openings into the inner ear. It is closed off from the middle ear by the round window membrane, which vibrates with opposite phase to vibrations entering the inner ear through the oval window. It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
The secondary tympanic membrane (or round window membrane) covers the round window, sealing off one of two openings into the inner ear. It separates the scala tympani of the cochlea from the middle ear. It vibrates with opposite phase to vibrations entering the cochlea through the oval window as the fluid in the cochlea is displaced when pressed by the stapes at the oval window. This ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
54. Portal vein formation lies
A. behind the second part of duodenum
B. posterior to the neck of the pancreas ,r
C. posterior to the body of the pancreas
D. posterior to the tail of the pancreas
Ans b
The pancreas, an exocrine and endocrine gland, has a head, neck, body, and tail. The portal vein is formed posterior to the neck of the pancreas by the union of the superior mesenteric and splenic veins.
55. The knee joint is supported by all the following ligaments, EXCEPT
A. Anterior cruciate ligament
B. Inverted Y-shaped ligament of Bigelow
C. Oblique popliteal ligament
D. Fibular collateral ligament
Ans B
The iliofemoral ligament is a ligament of the hip joint which extends from the ilium to the femur in front of the joint. It is also referred to as the Y-ligament (see below) or the ligament of Bigelow, and any combinations of these names.
With a tensile strength exceeding 350 kg (772 lbs),[1] the iliofemoral ligament is not only stronger than the two other ligaments of the hip joint, the ischiofemoral and the pubofemoral, but also the strongest ligament in the human body and as such is an important constraint to the hip joint
56. Stimulation of J receptors causes all of the following EXCEPT
A. Bradycardia
B. Hypotension
C. Hypertension
D. Rapid breathing
Ans C
J-receptors (juxtacapillary) are nerves innervating into the body of the lung. They are present in the alveolar interstitium and are innervated by fibers of the vagus nerve.[1] J-receptors respond to events such as pulmonary edema, pulmonary emboli, pneumonia, congestive heart failure and barotrauma, which cause a decrease in oxygenation and thus lead to an increase in ventilation/respiration. They may be also stimulated by hyperinflation of the lung as well as intravenous or intracardiac administration of chemicals.
The stimulation of the J-receptors causes a reflex increase in breathing rate, and is also thought to be involved in the sensation of dyspnea, the subjective sensation of difficulty breathing. [2][3] The reflex response that is produced is apnea followed by rapid breathing, bradycardia, and hypotension (pulmonary chemoreflex). The physiologic role of this reflex is uncertain, but it probably occurs in pathologic states such as pulmonary congestion or embolization.[4] These receptors were discovered by Dr. A.S Paintal
57. The structures, outside the blood brain barrier are all the following, EXCEPT
A. Neurohypophysis.
B. Area postrema
C. OVLT
D. Locus ceruleus
Ans D
Circumventricular organs (CVOs) are structures in the brain that are characterized by their extensive vasculature and lack of a normal blood brain barrier (BBB).[1] The CVOs allow for the linkage between the central nervous system and peripheral blood flow; additionally they are an integral part of neuroendocrine function.[2] The lack of a blood brain barrier allows the CVOs to act as an alternative route for peptides and hormones in the neural tissue to the peripheral blood stream, while still protecting it from toxic substances.[3][4] CVOs can be classified in two ways, the sensory and the secretory organs.
The sensory organs include the area postrema (AP), the subfornical organ (SFO) and the organum vasculosum of lamina terminalis (OVLT.) They have the ability to sense plasma molecules and then pass that information into other regions of the brain. Through this, they provide direct information to the autonomic nervous system from systemic circulation
The secretory organs include the subcommissural organ (SCO), the posterior pituitary (also known as the neurohypophysis), the pineal gland, the median eminence and the intermediate lobe of the pituitary.[2] These organs are responsible for secreting hormones and glycoproteins into the peripheral vascular system using feedback from both the brain environment and external stimuli.
All of the circumventricular organs, besides the SCO, contain extensive vasculature and fenestrated capillaries which leads to a ‘leaky’ BBB at the site of the organs. Furthermore, all CVOs contain neural tissue, allowing them to play a role in the neuroendocrine system. It is highly debated if the choroid plexus can be included as a CVO. It has a high concentration of fenestrated capillaries, but its lack of neural tissue and its primary role of producing cerebrospinal fluid (CSF) usually excludes the choroid plexus from the CVO classificatio
The locus coeruleus (also spelled locus caeruleus) is a nucleus in the pons (part of the brainstem) involved with physiological responses to stress and panic
The locus coeruleus is the principal site for brain synthesis of norepinephrine (noradrenaline). The locus coeruleus and the areas of the body affected by the norepinephrine it produces are described collectively as the locus coeruleus-noradrenergic system or LC-NA system.[3] Norepinephrine may also be released directly into the blood from the adrenal medulla.
58. All are TRUE regarding erythropoietin, EXCEPT
A. In adults about 80% of it comes from the kidneys and 15% from the liver.
B. It 'is a glycoprotein with a molecular weight of about 34,000.
C. Its function is to stimulate red cell production, and its formation in response to hypoxia.
D. Its blood level is markedly decreased in anemia.
Ans D
EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production. It is a cytokine (protein signaling molecule) for erythrocyte (red blood cell) precursors in the bone marrow. Human EPO has a molecular weight of 34,000.
Erythropoietin levels in blood are quite low in the absence of anemia, at around 10 mU/mL. However, in hypoxic stress, EPO production may increase a 1000-fold, reaching 10,000 mU/mL of blood. EPO is produced mainly by peritubular capillary lining cells of the renal cortex; which are highly specialized epithelial-like cells. It is synthesized by renal peritubular cells in adults, with a small amount being produced in the liver
Regulation is believed to rely on a feed-back mechanism measuring blood oxygenation.[10] Constitutively synthesized transcription factors for EPO, known as hypoxia-inducible factors (HIFs), are hydroxylated and proteosomally digested in the presence of oxygen
59. The major stimulus for receptive relaxation of the stomach is
A. food in the stomach
B. food in the intestine
C. CCK
D. secretin
Ans A
Vagovagal reflex refers to gastrointestinal tract reflex circuits where afferent and efferent fibers of the vagus nerve[2] coordinate responses to gut stimuli via the dorsal vagal complex in the brain. The vagovagal reflex controls contraction of the gastrointestinal muscle layers in response to distension of the tract by food. This reflex also allows for the accommodation of large amounts of food in the gastrointestinal tracts.
The parasympathetic vagus nerve composed of both afferents and efferents carries signals from stretch receptors, osmoreceptors, and chemoreceptors to dorsal vagal complex where the signal may be further transmitted to autonomic centers in the medulla. Efferent fibers of the vagus then carry signals to the gastrointestinal tract up to 2/3 of the Tranverse Colon (coinciding with the second GI Watershed Point).
[edit]Function
The vagovagal reflex is active during the receptive relaxation of the stomach in response to swallowing of food (prior to it reaching the stomach).
When food enters the stomach a "vagovagal" reflex goes from the stomach to the brain, and then back again to the stomach causing active relaxation of the smooth muscle in the stomach wall.
If vagal innervation is interrupted then intra-gastric pressure increases.
The vagal afferents are activated during the gastric phase of digestion when the corpus and fundus of the stomach are distended secondary to the entry of a food bolus. The stimulation of the mechanical receptors located in the gastric mucosa stimulates the vagus afferents. The completion of the reflex circuit by vagus efferents leads to the stimulation of postganglionic muscarinic nerves. These nerves release acetylcholine to stimulate two end effects. One, the parietal cells in the body of the stomach are stimulated to release H+. Two, the ECL cells of the lamina propria of the body of the stomach are stimulated to release histamine. Vagal stimulation of the peptidergic neurons, occurring simultaneously, leads to the release of gastrin-releasing-peptide. Finally, the Delta cells are inhibited to reduce the inhibition of gastrin release.
60. Deuterium oxide is used to measure the volume of
A. extracellular fluid
B intracellular fluid
C plasma
D total body water
Ans D
Total body water (body composition) has been measured using stable isotopes of oxygen (oxygen-18) and deuterium (deuterium oxide, D2O) for more than 40 years. The principle is based on the theory that water is distributed in all parts of the body except body fat. Most researchers chose deuterium oxide to estimate total body water due to the lower cost of isotope. The 4% overestimation of total body water by the technique can be corrected in the final calculations.
A. Neurohypophysis.
B. Area postrema
C. OVLT
D. Locus ceruleus
Ans D
Circumventricular organs (CVOs) are structures in the brain that are characterized by their extensive vasculature and lack of a normal blood brain barrier (BBB).[1] The CVOs allow for the linkage between the central nervous system and peripheral blood flow; additionally they are an integral part of neuroendocrine function.[2] The lack of a blood brain barrier allows the CVOs to act as an alternative route for peptides and hormones in the neural tissue to the peripheral blood stream, while still protecting it from toxic substances.[3][4] CVOs can be classified in two ways, the sensory and the secretory organs.
The sensory organs include the area postrema (AP), the subfornical organ (SFO) and the organum vasculosum of lamina terminalis (OVLT.) They have the ability to sense plasma molecules and then pass that information into other regions of the brain. Through this, they provide direct information to the autonomic nervous system from systemic circulation
The secretory organs include the subcommissural organ (SCO), the posterior pituitary (also known as the neurohypophysis), the pineal gland, the median eminence and the intermediate lobe of the pituitary.[2] These organs are responsible for secreting hormones and glycoproteins into the peripheral vascular system using feedback from both the brain environment and external stimuli.
All of the circumventricular organs, besides the SCO, contain extensive vasculature and fenestrated capillaries which leads to a ‘leaky’ BBB at the site of the organs. Furthermore, all CVOs contain neural tissue, allowing them to play a role in the neuroendocrine system. It is highly debated if the choroid plexus can be included as a CVO. It has a high concentration of fenestrated capillaries, but its lack of neural tissue and its primary role of producing cerebrospinal fluid (CSF) usually excludes the choroid plexus from the CVO classificatio
The locus coeruleus (also spelled locus caeruleus) is a nucleus in the pons (part of the brainstem) involved with physiological responses to stress and panic
The locus coeruleus is the principal site for brain synthesis of norepinephrine (noradrenaline). The locus coeruleus and the areas of the body affected by the norepinephrine it produces are described collectively as the locus coeruleus-noradrenergic system or LC-NA system.[3] Norepinephrine may also be released directly into the blood from the adrenal medulla.
58. All are TRUE regarding erythropoietin, EXCEPT
A. In adults about 80% of it comes from the kidneys and 15% from the liver.
B. It 'is a glycoprotein with a molecular weight of about 34,000.
C. Its function is to stimulate red cell production, and its formation in response to hypoxia.
D. Its blood level is markedly decreased in anemia.
Ans D
EPO, is a glycoprotein hormone that controls erythropoiesis, or red blood cell production. It is a cytokine (protein signaling molecule) for erythrocyte (red blood cell) precursors in the bone marrow. Human EPO has a molecular weight of 34,000.
Erythropoietin levels in blood are quite low in the absence of anemia, at around 10 mU/mL. However, in hypoxic stress, EPO production may increase a 1000-fold, reaching 10,000 mU/mL of blood. EPO is produced mainly by peritubular capillary lining cells of the renal cortex; which are highly specialized epithelial-like cells. It is synthesized by renal peritubular cells in adults, with a small amount being produced in the liver
Regulation is believed to rely on a feed-back mechanism measuring blood oxygenation.[10] Constitutively synthesized transcription factors for EPO, known as hypoxia-inducible factors (HIFs), are hydroxylated and proteosomally digested in the presence of oxygen
59. The major stimulus for receptive relaxation of the stomach is
A. food in the stomach
B. food in the intestine
C. CCK
D. secretin
Ans A
Vagovagal reflex refers to gastrointestinal tract reflex circuits where afferent and efferent fibers of the vagus nerve[2] coordinate responses to gut stimuli via the dorsal vagal complex in the brain. The vagovagal reflex controls contraction of the gastrointestinal muscle layers in response to distension of the tract by food. This reflex also allows for the accommodation of large amounts of food in the gastrointestinal tracts.
The parasympathetic vagus nerve composed of both afferents and efferents carries signals from stretch receptors, osmoreceptors, and chemoreceptors to dorsal vagal complex where the signal may be further transmitted to autonomic centers in the medulla. Efferent fibers of the vagus then carry signals to the gastrointestinal tract up to 2/3 of the Tranverse Colon (coinciding with the second GI Watershed Point).
[edit]Function
The vagovagal reflex is active during the receptive relaxation of the stomach in response to swallowing of food (prior to it reaching the stomach).
When food enters the stomach a "vagovagal" reflex goes from the stomach to the brain, and then back again to the stomach causing active relaxation of the smooth muscle in the stomach wall.
If vagal innervation is interrupted then intra-gastric pressure increases.
The vagal afferents are activated during the gastric phase of digestion when the corpus and fundus of the stomach are distended secondary to the entry of a food bolus. The stimulation of the mechanical receptors located in the gastric mucosa stimulates the vagus afferents. The completion of the reflex circuit by vagus efferents leads to the stimulation of postganglionic muscarinic nerves. These nerves release acetylcholine to stimulate two end effects. One, the parietal cells in the body of the stomach are stimulated to release H+. Two, the ECL cells of the lamina propria of the body of the stomach are stimulated to release histamine. Vagal stimulation of the peptidergic neurons, occurring simultaneously, leads to the release of gastrin-releasing-peptide. Finally, the Delta cells are inhibited to reduce the inhibition of gastrin release.
60. Deuterium oxide is used to measure the volume of
A. extracellular fluid
B intracellular fluid
C plasma
D total body water
Ans D
Total body water (body composition) has been measured using stable isotopes of oxygen (oxygen-18) and deuterium (deuterium oxide, D2O) for more than 40 years. The principle is based on the theory that water is distributed in all parts of the body except body fat. Most researchers chose deuterium oxide to estimate total body water due to the lower cost of isotope. The 4% overestimation of total body water by the technique can be corrected in the final calculations.
61. All the following similarities are TRUE regarding DNA and RNA, EXCEPT `-
A. Both have adenine, guanine, cytosine
B. Pentose sugar is ribose
C. Main function involves protein biosynthesis
D. The bonding is in 3'-5' direction
Ans B
The chemical structure of RNA is very similar to that of DNA, but differ in three main ways:
• Unlike double-stranded DNA, RNA is a single-stranded molecule in many of its biological roles and has a much shorter chain of nucleotides. However, RNA can, by complementary base pairing, form intrastrand double helixes, as in tRNA.
• While DNA contains deoxyribose, RNA contains ribose (in deoxyribose there is no hydroxyl group attached to the pentose ring in the 2' position). These hydroxyl groups make RNA less stable than DNA because it is more prone to hydrolysis.
• The complementary base to adenine is not thymine, as it is in DNA, but rather uracil, which is an unmethylated form of thymine
62. One of the following has energy-rich bonds
A. Glucose
B. Long chain fatty acids
C. Gamma globulins
D. Guanosine triphosphate (GTP)
Ans D
63. Coenzyme A contains the Vitamin
A. Biotin
B. Niacin
C. Pyridoxine
D. Pantothenic acid
Pantothenic acid is found throughout living cells in the form of coenzyme A (CoA)
64. Blood levels of which of the following amino acids serve as an index of the increased risk of cardiovascular disease ?
A. Cysteine
B. Methionine
C. Homoserine
D. Homocysteine
Ans D
65. Profuse watery diarrhoea in Cholera is due to following action of its toxin
A. Phosphorylation of inhibitory G protein (Gi)
B. ADP ribosylation of stimulatory G protein (Gs)
C. ADP ribosylation of inhibitory G protein (Gi)
D. Phosphorylation of stimulatory G protein (Gs)
Ans B
CTA1 is then free to bind with a human partner protein called ADP-ribosylation factor 6 (Arf6); binding to Arf6 drives a change in the shape of CTA1 which exposes its active site and enables its catalytic activity.[5] The CTA1 fragment catalyses ADP-ribosylation of the Gαs proteins using NAD. The ADP-ribosylation causes the Gαs subunit to lose its catalytic activity in hydrolyzing GTP to GDP + Pi so it remains activated longer than normal. Increased Gαs activation leads to increased adenylate cyclase activity, which increases the intracellular concentration of cAMP to more than 100-fold over normal and over-activates cytosolic PKA.
66. Anti-platelet effect of Aspirin is due to inhibition of synthesis of
A. PGE2
B. PGI2
C. TXA2
D. PGF2
Ans C
TXA2 is generated from prostaglandin H2 by thromboxane-A synthase. Aspirin irreversibly inhibits platelet cyclooxygenase 1 preventing the formation of prostaglandin H2, and therefore thromboxane A2.
67. Which of the following 5-HT agonists is anti anxiety drug ?
A. Buspirone
B. Cisapride
C. Renzapride
D. Rizatriptan
Ans A
Buspirone functions as a serotonin 5-HT1A receptor partial agonist
It is this action that is thought to mediate its anxiolytic and antidepressant effects. Additionally, it functions as a presynaptic dopamine agonist D2,D3, dopamine antagonist D4,as well as a partial α1 receptor agonist
68. Which of the following statements is NOT correct about Sulfonylureas ?
A. Orally effective
B. Used in insulin dependent Diabetes Mellitus (Type-1)
C. Causes insulin secretion
D. Long term use down regulates sulfonylurea receptors
Ans B
69. A novel nicotinic agonist approved recently for use in smoking cessation is
A. rimonabant
B. varenicline
C. nefopam
D. pimozide
Ans B
Varenicline is a prescription medication used to treat smoking addiction. Varenicline is a nicotinic receptor partial agonist - it stimulates nicotine receptors more weakly than nicotine itself does. In this respect it is similar to cytisine and different from the nicotinic antagonist, bupropion, and nicotine replacement therapies (NRTs) like nicotine patches and nicotine gum. As a partial agonist it both reduces cravings for and decreases the pleasurable effects of cigarettes and other tobacco products. Through these mechanisms it can assist some patients to quit smoking.
70. Which of the following effects is NOT produced by Cholinomimetics ?
A. Miosis
B. Bronchospasm
C. Urinary retention
D. Spasm of accommodation
Ans C
B. Pentose sugar is ribose
C. Main function involves protein biosynthesis
D. The bonding is in 3'-5' direction
Ans B
The chemical structure of RNA is very similar to that of DNA, but differ in three main ways:
• Unlike double-stranded DNA, RNA is a single-stranded molecule in many of its biological roles and has a much shorter chain of nucleotides. However, RNA can, by complementary base pairing, form intrastrand double helixes, as in tRNA.
• While DNA contains deoxyribose, RNA contains ribose (in deoxyribose there is no hydroxyl group attached to the pentose ring in the 2' position). These hydroxyl groups make RNA less stable than DNA because it is more prone to hydrolysis.
• The complementary base to adenine is not thymine, as it is in DNA, but rather uracil, which is an unmethylated form of thymine
62. One of the following has energy-rich bonds
A. Glucose
B. Long chain fatty acids
C. Gamma globulins
D. Guanosine triphosphate (GTP)
Ans D
63. Coenzyme A contains the Vitamin
A. Biotin
B. Niacin
C. Pyridoxine
D. Pantothenic acid
Pantothenic acid is found throughout living cells in the form of coenzyme A (CoA)
64. Blood levels of which of the following amino acids serve as an index of the increased risk of cardiovascular disease ?
A. Cysteine
B. Methionine
C. Homoserine
D. Homocysteine
Ans D
65. Profuse watery diarrhoea in Cholera is due to following action of its toxin
A. Phosphorylation of inhibitory G protein (Gi)
B. ADP ribosylation of stimulatory G protein (Gs)
C. ADP ribosylation of inhibitory G protein (Gi)
D. Phosphorylation of stimulatory G protein (Gs)
Ans B
CTA1 is then free to bind with a human partner protein called ADP-ribosylation factor 6 (Arf6); binding to Arf6 drives a change in the shape of CTA1 which exposes its active site and enables its catalytic activity.[5] The CTA1 fragment catalyses ADP-ribosylation of the Gαs proteins using NAD. The ADP-ribosylation causes the Gαs subunit to lose its catalytic activity in hydrolyzing GTP to GDP + Pi so it remains activated longer than normal. Increased Gαs activation leads to increased adenylate cyclase activity, which increases the intracellular concentration of cAMP to more than 100-fold over normal and over-activates cytosolic PKA.
66. Anti-platelet effect of Aspirin is due to inhibition of synthesis of
A. PGE2
B. PGI2
C. TXA2
D. PGF2
Ans C
TXA2 is generated from prostaglandin H2 by thromboxane-A synthase. Aspirin irreversibly inhibits platelet cyclooxygenase 1 preventing the formation of prostaglandin H2, and therefore thromboxane A2.
67. Which of the following 5-HT agonists is anti anxiety drug ?
A. Buspirone
B. Cisapride
C. Renzapride
D. Rizatriptan
Ans A
Buspirone functions as a serotonin 5-HT1A receptor partial agonist
It is this action that is thought to mediate its anxiolytic and antidepressant effects. Additionally, it functions as a presynaptic dopamine agonist D2,D3, dopamine antagonist D4,as well as a partial α1 receptor agonist
68. Which of the following statements is NOT correct about Sulfonylureas ?
A. Orally effective
B. Used in insulin dependent Diabetes Mellitus (Type-1)
C. Causes insulin secretion
D. Long term use down regulates sulfonylurea receptors
Ans B
69. A novel nicotinic agonist approved recently for use in smoking cessation is
A. rimonabant
B. varenicline
C. nefopam
D. pimozide
Ans B
Varenicline is a prescription medication used to treat smoking addiction. Varenicline is a nicotinic receptor partial agonist - it stimulates nicotine receptors more weakly than nicotine itself does. In this respect it is similar to cytisine and different from the nicotinic antagonist, bupropion, and nicotine replacement therapies (NRTs) like nicotine patches and nicotine gum. As a partial agonist it both reduces cravings for and decreases the pleasurable effects of cigarettes and other tobacco products. Through these mechanisms it can assist some patients to quit smoking.
70. Which of the following effects is NOT produced by Cholinomimetics ?
A. Miosis
B. Bronchospasm
C. Urinary retention
D. Spasm of accommodation
Ans C
71. An organism that does NOT grow at normal atmospheric tension but requires traces of oxygen in metabolism is known as
A. microaerophilic
B. capnophilic
C. facultative anaerobe
D. aerotolerant anaerobe
Ans A
A microaerophile is a microorganism that requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the atmosphere (~20% concentration). Many microphiles are also capnophiles, as they require an elevated concentration of carbon dioxide. In the laboratory they can be easily cultivated in a candle jar. A candle jar is a container into which a lit candle is introduced before sealing the container's airtight lid. The candle's flame burns until extinguished by oxygen deprivation, which creates a carbon dioxide-rich, oxygen-poor atmosphere in the jar.
Examples include:
Borrelia burgdorferi, a species of spirochaete bacteria that causes Lyme disease in humans.
Helicobacter pylori, a species of proteobacteria that has been linked to peptic ulcers and some types of gastritis. Some do not consider it a true obligate microaerophile.[1]
Campylobacter has been described as microaerophilic.[2]
Streptococcus intermedius has also been described as microaerophilic.
Streptococcus pyogenes, a well known microaerophile that causes streptococcal pharyngitis.
72. Intracellular survival of M.tuberculosis is due to
A. Interference with oxidative burst
B. Prevention of fusion of phagosome with lysosome
C. Inhibition of degranulation
D. Resistance to lysosomal enzymes
Ans B
Intracellular parasites (e.g., Mycobacterium tuberculosis, Toxoplasma gondii, and some Chlamydiae) may promote their survival within the host by acting from within phagosomes to prevent phagolysosome formation, thus avoiding exposure to the lysosomal hydrolases
73. Enterotest is done for the diagnosis of
A. Intestinal amoebiasis
B. Trypanosomiasis
C. Giardiasis
D. Leishmaniasis
Ans C
It is well recognised that stool examination is an unsatis- factory method of searching for Giardia lamblia. The parasite lives primarily in the duodenum and jejunum and is therefore more readily found in duodenojejunal aspirate'. The parasite is excreted in intermittent 'showers' and it is therefore likely that an isolated stool specimen could be negative despite a heavy Giardia lamblia infes- tation. The Enterotest is a simple and safe way of sampling duodenojejunal contents. We have compared this method with examination of stools and the aspirate from the Crosby capsule, obtained at jejunal biopsy.
74. All are vapour phase disinfectants, EXCEPT
A. Ethylene oxide
B. Thiomersal
C. Formaldehyde gas
D. Betapropiolactone (BPL)
Ans B
Vapor-phase Disinfectants
Propiolactone is used for vaccines, tissue grafts, surgical instruments, and enzymes, as a sterilant of blood plasma, water, milk, and nutrient broth, and as a vapor-phase disinfectant in enclosed spaces. Acute (short-term) inhalation exposure to beta-propiolactone causes severe irritation of the eyes, nose, throat, and respiratory tract in humans.
Alkylating agents such as formaldehyde, ethylene oxide, and propylene oxide are broad-spectrum biocides active against bacteria, viruses, and fungi, including spores.
Ethylene and propylene oxides are highly reactive gaseous fumigants used for sterilizing animal feed, human food, surgical equipment that cannot be autoclaved (eg, endoscopes, gloves, syringes, catheters, tubing, implantable devices), laboratory equipment, etc. Both are noncorrosive. However, ethylene oxide has better penetrability than propylene oxide and, therefore, is more commonly used. For this application, ethylene oxide is mixed with chlorofluorocarbons or carbon dioxide and sold in gas cylinders.
Other gaseous disinfectants (eg, formaldehyde, sulfur dioxide, methylbromide) have been used infrequently because of their toxic or corrosive properties.
Thiomersal (INN), commonly known in the US as thimerosal, is an organomercury compound. This compound is a well established antiseptic and antifungal agent.
75. Mice are used for isolation of all of the following EXCEPT
A.Rabies virus
B.Arbovirus
C.Coxsackie virus
D.Echo viruses
Ans D
Coxsackie A - some will grow in Rhadomyosarcoma (Rd) cell lines. Otherwise will require innoculation into newborn mice
Virus isolation - intracerebral inoculation of laboratory mice is the method of choice. Rabies virus will propagate in a variety of cell cultures including human diploid cells but have not replaced the mouse system
Arboviruses
1. Virus isolation - the arbovirus is usually present in the blood during the acute febrile phase of the illness. To reduce the effect of serum inhibitors, isolation attempts should be made not only with undiluted serum, but dilutions of 1:5 or 1:10 or higher. Virus isolation is not usually attempted from tissue biopsies with the exception of brain tissue from patients with encephalitis. 3 systems are available for virus isolation;-
a. intracerebral inoculation of newborn mice
b. tissue culture eg. LLC-MK2, Vero, artrhopod cell lines
intrathoracic inoculation of arthropods
A. microaerophilic
B. capnophilic
C. facultative anaerobe
D. aerotolerant anaerobe
Ans A
A microaerophile is a microorganism that requires oxygen to survive, but requires environments containing lower levels of oxygen than are present in the atmosphere (~20% concentration). Many microphiles are also capnophiles, as they require an elevated concentration of carbon dioxide. In the laboratory they can be easily cultivated in a candle jar. A candle jar is a container into which a lit candle is introduced before sealing the container's airtight lid. The candle's flame burns until extinguished by oxygen deprivation, which creates a carbon dioxide-rich, oxygen-poor atmosphere in the jar.
Examples include:
Borrelia burgdorferi, a species of spirochaete bacteria that causes Lyme disease in humans.
Helicobacter pylori, a species of proteobacteria that has been linked to peptic ulcers and some types of gastritis. Some do not consider it a true obligate microaerophile.[1]
Campylobacter has been described as microaerophilic.[2]
Streptococcus intermedius has also been described as microaerophilic.
Streptococcus pyogenes, a well known microaerophile that causes streptococcal pharyngitis.
72. Intracellular survival of M.tuberculosis is due to
A. Interference with oxidative burst
B. Prevention of fusion of phagosome with lysosome
C. Inhibition of degranulation
D. Resistance to lysosomal enzymes
Ans B
Intracellular parasites (e.g., Mycobacterium tuberculosis, Toxoplasma gondii, and some Chlamydiae) may promote their survival within the host by acting from within phagosomes to prevent phagolysosome formation, thus avoiding exposure to the lysosomal hydrolases
73. Enterotest is done for the diagnosis of
A. Intestinal amoebiasis
B. Trypanosomiasis
C. Giardiasis
D. Leishmaniasis
Ans C
It is well recognised that stool examination is an unsatis- factory method of searching for Giardia lamblia. The parasite lives primarily in the duodenum and jejunum and is therefore more readily found in duodenojejunal aspirate'. The parasite is excreted in intermittent 'showers' and it is therefore likely that an isolated stool specimen could be negative despite a heavy Giardia lamblia infes- tation. The Enterotest is a simple and safe way of sampling duodenojejunal contents. We have compared this method with examination of stools and the aspirate from the Crosby capsule, obtained at jejunal biopsy.
74. All are vapour phase disinfectants, EXCEPT
A. Ethylene oxide
B. Thiomersal
C. Formaldehyde gas
D. Betapropiolactone (BPL)
Ans B
Vapor-phase Disinfectants
Propiolactone is used for vaccines, tissue grafts, surgical instruments, and enzymes, as a sterilant of blood plasma, water, milk, and nutrient broth, and as a vapor-phase disinfectant in enclosed spaces. Acute (short-term) inhalation exposure to beta-propiolactone causes severe irritation of the eyes, nose, throat, and respiratory tract in humans.
Alkylating agents such as formaldehyde, ethylene oxide, and propylene oxide are broad-spectrum biocides active against bacteria, viruses, and fungi, including spores.
Ethylene and propylene oxides are highly reactive gaseous fumigants used for sterilizing animal feed, human food, surgical equipment that cannot be autoclaved (eg, endoscopes, gloves, syringes, catheters, tubing, implantable devices), laboratory equipment, etc. Both are noncorrosive. However, ethylene oxide has better penetrability than propylene oxide and, therefore, is more commonly used. For this application, ethylene oxide is mixed with chlorofluorocarbons or carbon dioxide and sold in gas cylinders.
Other gaseous disinfectants (eg, formaldehyde, sulfur dioxide, methylbromide) have been used infrequently because of their toxic or corrosive properties.
Thiomersal (INN), commonly known in the US as thimerosal, is an organomercury compound. This compound is a well established antiseptic and antifungal agent.
75. Mice are used for isolation of all of the following EXCEPT
A.Rabies virus
B.Arbovirus
C.Coxsackie virus
D.Echo viruses
Ans D
Coxsackie A - some will grow in Rhadomyosarcoma (Rd) cell lines. Otherwise will require innoculation into newborn mice
Virus isolation - intracerebral inoculation of laboratory mice is the method of choice. Rabies virus will propagate in a variety of cell cultures including human diploid cells but have not replaced the mouse system
Arboviruses
1. Virus isolation - the arbovirus is usually present in the blood during the acute febrile phase of the illness. To reduce the effect of serum inhibitors, isolation attempts should be made not only with undiluted serum, but dilutions of 1:5 or 1:10 or higher. Virus isolation is not usually attempted from tissue biopsies with the exception of brain tissue from patients with encephalitis. 3 systems are available for virus isolation;-
a. intracerebral inoculation of newborn mice
b. tissue culture eg. LLC-MK2, Vero, artrhopod cell lines
intrathoracic inoculation of arthropods
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