NEET-PG 2015 Practice Questions

Q: Blood testis barrier in testis is formed by?

Sertoli cells. ***Sertoli cells*** - **Sertoli cells** form tight junctions with each other, creating the **blood-testis barrier** [1] - This barrier divides the seminiferous epithelium into **basal and adluminal compartments** [1] - Essential for protecting developing **germ cells** from immune attack and maintaining a specialized microenvironment for **spermatogenesis** [1] - The tight junctions between Sertoli cells are among the tightest in the human body *Granulosa cells* - **Granulosa cells** are found in the **ovary**, not the testis - They surround the oocyte in ovarian follicles and produce **estrogen** - Completely unrelated to testicular structure or function *Germ cells* - **Germ cells** (spermatogonia, spermatocytes, spermatids, spermatozoa) are the developing sperm cells [1] - They are **protected by** the blood-testis barrier, not forming it [1] - Located within the seminiferous tubules but do not create barrier structures [1] *Leydig cells* - **Leydig cells** are interstitial cells located in the connective tissue **between seminiferous tubules** - Their primary function is production of **testosterone**, not forming barriers [2] - They are outside the seminiferous tubules and not involved in barrier formation [2]

Q: Which of the following stimulates Acetyl CoA Carboxylase?

Citrate. ***Citrate*** - **Citrate** is an allosteric activator of **Acetyl-CoA Carboxylase (ACC)**, indicating abundant energy and precursor availability for fatty acid synthesis. - This activation promotes the conversion of **Acetyl-CoA** to **Malonyl-CoA**, the committed step in **fatty acid synthesis**. *Starvation* - **Starvation** leads to energy deficit, which generally **inhibits** anabolic processes like fatty acid synthesis. - In this state, enzymes involved in anabolic pathways are often downregulated or inhibited to conserve energy. *Glucagon* - **Glucagon** is a hormone that signals low blood glucose and promotes catabolic processes such as **glycogenolysis** and **gluconeogenesis**. - It **inhibits** fatty acid synthesis by phosphorylating and inactivating **Acetyl-CoA Carboxylase**, thus opposing citrate's activating effect. *None of the options* - **Citrate** is a known stimulator of Acetyl CoA Carboxylase. - This option is incorrect because there is a correct answer among the choices.

Q: Which protein does the domain of plasminogen resemble?

Apolipoprotein (a) (a lipoprotein). ***Apolipoprotein (a) (a lipoprotein)*** - **Plasminogen** and **apolipoprotein (a)** share structural homology, specifically due to the presence of **kringle domains**. - This structural similarity suggests a potential for apolipoprotein (a) to **interfere with plasminogen’s fibrinolytic activity**, contributing to **atherosclerosis**. *Fibrinogen (a clotting protein)* - While plasmin acts on fibrinogen (and its derivative fibrin), its domain structure does not **resemble fibrinogen**. - **Fibrinogen** is a large, multi-domain glycoprotein crucial for **clot formation**, distinct from plasminogen's primarily **kringle-rich structure**. *LDL receptor (a lipid metabolism protein)* - The **LDL receptor** is involved in **cholesterol uptake** by cells and has structural features like ligand-binding repeats and epidermal growth factor (EGF) repeats. - Its domain structure is **not similar to plasminogen**, which is characterized by **kringle domains** and a protease domain. *Prothrombin (a coagulation protein)* - **Prothrombin** is a precursor to thrombin, featuring **gla domains**, kringle-like domains (though structurally distinct from plasminogen's), and a serine protease domain. - While both are involved in coagulation/fibrinolysis, their **overall domain arrangements and specific kringle structures differ** significantly.

Q: Caisson's disease is primarily associated with which of the following?

Underwater construction workers. ***Underwater construction workers*** - Caisson's disease, also known as **decompression sickness (DCS)**, is historically linked to workers in **caissons**, which are watertight structures used for underwater construction. - These workers experience changes in pressure that can lead to nitrogen bubbles forming in their tissues upon surfacing, causing the characteristic symptoms of DCS. *Rapid ascent in aircraft* - While rapid ascent in aircraft can cause **decompression sickness**, especially in unpressurized cabins, it is not the primary association for the historical term "Caisson's disease." - The term "Caisson's disease" specifically refers to the condition in workers exposed to **high atmospheric pressure** during underwater construction. *None of the options* - This option is incorrect because **underwater construction workers** are directly associated with Caisson's disease. - The question has a correct and specific answer. *Rapid ascent of deep sea divers* - **Deep-sea divers** are susceptible to decompression sickness due to rapid ascent, which is physiologically similar to Caisson's disease. - However, the specific term "Caisson's disease" most directly refers to the historical experience of **underwater construction workers** in caissons.

Q: What is the immediate emergency treatment for carbon monoxide (CO) poisoning?

High flow O2. ***High flow O2*** - **High-flow oxygen** is the immediate emergency treatment for CO poisoning because it helps to displace CO from **hemoglobin**, thereby increasing oxygen delivery to tissues [1], [2]. - CO has a much **higher affinity** for hemoglobin than oxygen, so administering high concentrations of oxygen helps to reverse this binding and accelerate CO elimination [2]. *5% CO2 inhalation* - Administering **CO2** would worsen the patient's condition as it can cause **respiratory acidosis** and increase cerebral blood flow, potentially exacerbating CO toxicity. - CO2 inhalation would not effectively displace **carbon monoxide** from hemoglobin. *10% CO2 inhalation* - Similar to 5% CO2, **10% CO2 inhalation** would be detrimental, leading to significant **acidosis** and further compromising respiratory function. - This treatment does not address the primary issue of **carbon monoxide** binding to **hemoglobin** [2]. *Nitroglycerine* - **Nitroglycerine** is a vasodilator primarily used for conditions like **angina** or **heart failure**; it has no role in treating CO poisoning. - It would not help in displacing **carbon monoxide** or improving tissue oxygenation.

Q: Which of the following drugs is NOT metabolized by acetylation?

Metoclopramide. ***Metoclopramide*** - **Metoclopramide** is eliminated primarily via renal excretion, with a smaller portion undergoing glucuronidation and sulfation, not acetylation. - Its metabolic pathway does not involve the enzyme **N-acetyltransferase**, which is responsible for acetylation. *Dapsone* - **Dapsone** undergoes significant **N-acetylation** by NAT2 (N-acetyltransferase 2), which is important for its metabolism and clearance. - Genetic variations in NAT2 can lead to individual differences in **dapsone acetylation rates**, affecting drug efficacy and toxicity. *Procainamide* - **Procainamide** is primarily metabolized by N-acetyltransferase 2 (NAT2) to **N-acetylprocainamide (NAPA)**, an active metabolite. - Differences in **acetylation phenotype** (slow vs. rapid acetylators) influence the metabolism of procainamide and the risk of drug-induced lupus. *INH* - **Isoniazid (INH)** is extensively metabolized in the liver, primarily by **N-acetylation** via the enzyme N-acetyltransferase 2 (NAT2). - The rate of INH acetylation varies significantly among individuals, classifying them as **slow or rapid acetylators**, which impacts drug toxicity and efficacy.

Q: What is Proaccelerin?

Factor V. ***Factor V*** - **Factor V**, also known as **proaccelerin** or **labile factor**, is a **plasma protein** that plays a crucial role in the coagulation cascade. - It is activated by thrombin to **Factor Va**, which then combines with Factor Xa, calcium, and phospholipid to form the **prothrombinase complex**, significantly enhancing thrombin generation. *Factor II* - **Factor II** is **prothrombin**, a precursor to **thrombin**, which is central to coagulation. - It is not referred to as preaccelerin. *Factor VII* - **Factor VII** is primarily involved in the **extrinsic pathway** of coagulation, becoming activated to Factor VIIa upon contact with tissue factor. - It works to activate Factor IX and Factor X, but it is not preaccelerin. *Factor X* - **Factor X**, also known as **Stuart-Prower factor**, is a key enzyme in the **common pathway** of coagulation, converting prothrombin to thrombin. - It is distinct from Factor V, which acts as a cofactor.

Q: Regarding Caisson's disease which statement among the following is CORRECT?

Pain in the joints is due to nitrogen bubbles. ***Pain in the joints is due to nitrogen bubbles*** - Caisson's disease, or **decompression sickness**, is characterized by the formation of nitrogen gas bubbles in tissues and blood due to rapid depressurization. - These gas bubbles can accumulate in joints, causing **severe pain** often referred to as "the bends." *Lung damage is caused by air embolism* - While air embolism can occur due to **pulmonary barotrauma** during ascent (rapid depressurization), the primary lung damage associated with decompression sickness is not typically directly caused by an air embolism reaching the lungs from within the body. - Air embolism from pulmonary barotrauma is a distinct complication, where air from ruptured alveoli enters the arterial circulation, potentially leading to cerebral or cardiac ischemia. *Tremors are seen due to nitrogen narcosis* - **Nitrogen narcosis** is a condition that occurs at high ambient pressures when breathing compressed air, causing a reversible alteration in consciousness similar to alcohol intoxication, but it does not primarily cause tremors. - Tremors are more characteristic of other neurological conditions or high-pressure nervous syndrome, not nitrogen narcosis itself. *High pressure Nervous syndrome can be prevented by using mixtures of Oxygen & Helium* - **High-pressure nervous syndrome (HPNS)** is indeed associated with deep dives using helium-oxygen mixtures. Its symptoms include tremors. - HPNS is actually **prevented or mitigated** by adding small amounts of narcotic gases like nitrogen to the helium-oxygen mixture (e.g., trimix) to counteract the excitatory effects of helium, rather than solely using oxygen and helium.

Q: Solution currently used for liver preservation for transplantation is?

University of Wisconsin (UW) solution. ***University of Wisconsin (UW) solution*** - The **University of Wisconsin (UW) solution** is widely considered the gold standard for **organ preservation**, particularly for liver transplantation, due to its superior ability to extend cold ischemia time. - It contains a unique blend of components, including **lactobionate, raffinose, and hydroxyethyl starch**, which help to minimize cellular swelling, prevent free radical injury, and maintain cellular integrity during cold storage. *IGL-1 solution* - **IGL-1** is a more recent preservation solution designed to be used with **machine perfusion** systems. - While showing promise, it is **not yet as universally adopted** as UW solution for static cold storage of livers. *Ross Marshall Citrate solution* - The **Ross Marshall Citrate solution** was an older solution primarily used for **kidney preservation**. - It has been largely **superseded by newer solutions** with improved efficacy for liver and other organ preservation. *Kyoto ET solution* - **Kyoto ET solution** is another preservation solution primarily used in **Japan**, particularly for **kidney and pancreas preservation**. - While effective for those organs, it is **not the most commonly used** or preferred solution for liver preservation globally.

Question 1

Blood testis barrier in testis is formed by?

Accepted Answer

Sertoli cells

Answer

Germ cells

Answer

Leydig cells

Answer

Granulosa cells

Question 2

Which of the following stimulates Acetyl CoA Carboxylase?

Accepted Answer

Citrate

Answer

Starvation

Answer

Glucagon

Answer

None of the options

Question 3

Which protein does the domain of plasminogen resemble?

Accepted Answer

Apolipoprotein (a) (a lipoprotein)

Answer

Fibrinogen (a clotting protein)

Answer

LDL receptor (a lipid metabolism protein)

Answer

Prothrombin (a coagulation protein)

Question 4

Caisson's disease is primarily associated with which of the following?

Accepted Answer

Underwater construction workers

Answer

None of the options

Answer

Rapid ascent in aircraft

Answer

Rapid ascent of deep sea divers

Question 5

What is the immediate emergency treatment for carbon monoxide (CO) poisoning?

Accepted Answer

High flow O2

Answer

5% CO2 inhalation

Answer

10% CO2 inhalation

Answer

Nitroglycerine

Question 6

Which of the following statements about Niemann-Pick disease is false?

Accepted Answer

Type B Niemann-Pick disease is characterized by severe neurological symptoms.

Answer

Due to deficiency of sphingomyelinase.

Answer

CNS symptoms are present in type A.

Answer

Histiocytes show PAS positive inclusions, and Type A is more severe.

Question 7

Which of the following drugs is NOT metabolized by acetylation?

Accepted Answer

Metoclopramide

Answer

Dapsone

Answer

Procainamide

Answer

INH

Question 8

What is Proaccelerin?

Accepted Answer

Factor V

Answer

Factor VII

Answer

Factor II

Answer

Factor X

Question 9

Regarding Caisson's disease which statement among the following is CORRECT?

Accepted Answer

Pain in the joints is due to nitrogen bubbles

Answer

Lung damage is caused by air embolism

Answer

Tremors are seen due to nitrogen narcosis

Answer

High pressure Nervous syndrome can be prevented by using mixtures of Oxygen & Helium

Question 10

Solution currently used for liver preservation for transplantation is?

Accepted Answer

University of Wisconsin (UW) solution

Answer

IGL-1 solution

Answer

Ross Marshall Citrate solution

Answer

Kyoto ET solution

NEET-PG 2015

Anatomy

Biochemistry

Community Medicine

Internal Medicine

Pathology

Pharmacology

Physiology

Surgery