NEET-PG 2012 Practice Questions

Q: Which disease is most closely associated with intensive international surveillance for global eradication?

Polio. **Polio** - **Polio** has been the focus of an intensive global eradication campaign, requiring robust **international surveillance** to track cases, mutations, and vaccine-derived polioviruses. - The **Global Polio Eradication Initiative (GPEI)**, a major international collaboration, relies heavily on coordinated surveillance efforts to ensure no wild poliovirus remains undetected. *Hepatitis* - While **hepatitis** is a significant global health burden, particularly hepatitis B and C, it is not subject to the same level of internationally coordinated, aggressive surveillance aimed at **global eradication** as polio. - Surveillance for hepatitis often focuses on prevalence, incidence, and risk factors at national and regional levels rather than a centralized, real-time eradication tracking system. *TB* - **Tuberculosis (TB)** is a major global health concern, and there are international efforts for control and elimination, but it is not currently targeted for **global eradication** in the same manner as polio. - Surveillance for TB often involves tracking drug-resistant strains and treatment outcomes, but it doesn't involve the immediate, outbreak-focused international alert system seen with diseases like polio or novel pandemics. *Leprosy* - **Leprosy** is a neglected tropical disease, and while there are international efforts for its control and elimination, primarily led by the WHO, it does not involve the same level of intensive, real-time global surveillance for eradication as **polio**. - Surveillance for leprosy is typically focused on case detection, treatment completion, and identifying areas with high endemicity rather than rapid international notification of individual cases for eradication purposes.

Q: Which of the following is not a source of environmental radiation?

CO. ***CO*** - **Carbon monoxide (CO)** is a toxic gas produced by incomplete combustion, but it is **not radioactive** and thus not a source of environmental radiation. - Its danger comes from its ability to bind to **hemoglobin**, preventing oxygen transport, not from emitting radiation. *Radium* - **Radium** is a highly **radioactive element** found naturally in the environment as a decay product of uranium and thorium. - It emits **alpha and gamma radiation**, contributing significantly to natural background radiation. *Uranium* - **Uranium** is a naturally occurring **radioactive element** found in rocks, soil, and water. - It decays through a series of steps, emitting **alpha, beta, and gamma radiation**, and is a primary source of environmental background radiation. *Radon* - **Radon** is a **radioactive gas** that is formed from the decay of uranium in soil and rocks. - It is a significant source of **indoor environmental radiation exposure** and a known cause of lung cancer.

Q: What does a highly sensitive test imply about its false negative rate?

Low false negative rate. ***Low false negative rate*** - A highly **sensitive test** is good at identifying true positives, meaning it correctly identifies most people who have the disease. - Sensitivity = TP/(TP+FN), so high sensitivity mathematically means few false negatives. - This characteristic directly translates to a **low false negative rate**, as few people with the disease will be missed. *High false positive rate* - A high **false positive rate** relates to **specificity**, not sensitivity. - False positive rate = FP/(FP+TN), which measures how many healthy people are incorrectly identified as diseased. - While some sensitive tests may have lower specificity (higher FP rate), this is not a direct implication of high sensitivity. *High true negative rate* - A high **true negative rate** is a characteristic of a highly **specific** test, which correctly identifies people who do **not** have the disease. - True negative rate = TN/(TN+FP) = Specificity. - **Sensitivity** and **specificity** are independent measures, so high sensitivity does not imply a high true negative rate. *High true positive rate* - High **true positive rate** is actually another term for high sensitivity (Sensitivity = TPR = TP/(TP+FN)). - While this is true of a sensitive test, the question specifically asks about the implication for the **false negative rate**. - The **most direct answer** regarding false negatives is "low false negative rate" rather than describing the true positive rate.

Q: In the context of epidemiology, what is the denominator used for calculating incidence?

Population at risk. ***Population at risk*** - Incidence measures the **rate of new cases** of a disease in a population over a specified period. - The denominator for calculating incidence must exclude individuals who are **already diseased** or are **immune** and thus not susceptible to developing the condition. - This is the **most accurate and theoretically correct** denominator as it represents only those who can actually develop the disease. *Mid year population* - While often used as a **practical approximation** in epidemiological calculations when the exact population at risk is difficult to determine. - However, it includes individuals who may not be at risk (e.g., already have the disease or are immune), making it **less precise** than using the actual susceptible population. - For the **theoretical definition** of incidence rate, population at risk is the correct denominator. *Total number of cases* - This value represents the **numerator** for incidence calculations, as it counts the number of new events or diseases occurring. - It cannot serve as the denominator, as the denominator must reflect the pool of individuals from which these **new cases arose**. *Total number of deaths* - This is a measure of **mortality**, not incidence, and is used to calculate death rates. - The denominator for mortality rates is typically the **population at risk of death**, not specifically the population at risk of developing a disease.

Q: What is the first external sign of decomposition of a dead body?

Greenish discolouration over right iliac fossa. ***Greenish discolouration over right iliac fossa*** - The **first external sign of decomposition** is typically a **greenish discoloration** that appears over the **right iliac fossa**. - This occurs due to the breakdown of **hemoglobin** by bacteria, particularly *Clostridium perfringens*, in the **cecum**, which is located in this region. - It typically appears **12-24 hours after death** under normal environmental conditions. *Decomposition of liver and intestine* - While internal organs like the liver and intestine do decompose, their decomposition is an **internal process** and not the **first external sign**. - Internal putrefaction precedes external signs but is not visually observable from the exterior initially. *Greenish discolouration over dependent parts* - Greenish discolouration over dependent parts represents a **later stage of decomposition** when putrefactive changes spread throughout the body. - This occurs after the initial greenish discoloration in the right iliac fossa as bacterial action and gases spread from the intestines to other body regions. - This is NOT the first external sign but rather a progression of decomposition. *Blood stained froth from mouth* - **Blood-stained froth from the mouth** can be seen in various conditions, such as **drowning**, **pulmonary edema**, or certain types of poisoning, but it is not related to decomposition. - This finding is more indicative of the cause of death or agonal/perimortem changes rather than postmortem decomposition.

Q: Binding of gp120 causes:

Facilitation of co-receptor binding. ***Facilitation of co-receptor*** - **gp120** binding to the **CD4 receptor** on target cells induces a conformational change in gp120, which then exposes or creates a binding site for a **chemokine co-receptor** (CCR5 or CXCR4). - This interaction is crucial for the subsequent steps of viral entry, as it allows the virus to make further contact with the cell surface. *Infection of target cell* - While binding of gp120 is the *first step* in infection, it does not directly cause the infection itself. - Infection occurs after a series of events including co-receptor binding, membrane fusion, and reverse transcription. *Fusing of virus and target cell* - **Fusion** of the viral and cellular membranes is primarily mediated by **gp41**, which is part of the gp160 envelope glycoprotein complex alongside gp120. - This fusion event *follows* the binding of gp120 to CD4 and the co-receptor, as gp120 binding initiates the conformational changes that expose and activate gp41. *None of the options* - One of the provided options accurately describes a direct consequence of gp120 binding, making this option incorrect.

Q: Who discovered the malarial parasite?

Charles Louis Alphonse Laveran. ***Charles Louis Alphonse Laveran*** - **Charles Louis Alphonse Laveran** was a French physician who, in **1880**, observed parasites in the blood of a malaria patient. - He was awarded the **Nobel Prize in Physiology or Medicine in 1907** for his discovery of the role of protozoa in causing diseases, specifically recognizing the malarial parasite. *Ronald Ross* - **Ronald Ross** was a British physician who, in **1897**, demonstrated that **malaria is transmitted by mosquitoes**. - While he elucidated the **transmission cycle**, it was Laveran who first identified the parasite itself in human blood. - He received the **Nobel Prize in 1902** for this work. *Paul Muller* - **Paul Muller** was a Swiss chemist who was awarded the **Nobel Prize in Physiology or Medicine in 1948** for his discovery of the insecticidal properties of **DDT (dichlorodiphenyltrichloroethane)**. - His work was significant in combating insect-borne diseases like malaria, but he was not involved in the discovery of the malarial parasite. *Pampania* - This name does not correspond to any recognized figure in the discovery of the malarial parasite or its transmission. - This is a distractor option in the original examination question.

Q: What type of deposit is commonly associated with age-related macular degeneration?

Drusen. ***Drusen*** - **Drusen** are yellow deposits of extracellular material that accumulate beneath the **retinal pigment epithelium (RPE)**. - Their presence is a hallmark sign of **age-related macular degeneration (AMD)** and can lead to vision loss by disrupting retinal function. *Iron* - While iron can accumulate in ocular tissues in conditions like **siderosis bulbi** (due to retained intraocular foreign bodies), it is not a characteristic deposit of macular degeneration. - Ocular iron deposition typically causes different pathologies, such as retinal dysfunction or glaucoma, rather than AMD. *Lipochrome* - **Lipochrome** refers to a class of pigments, including **lipofuscin**, which can accumulate in cells as a byproduct of cellular metabolism and aging. - Although lipofuscin buildup occurs in the RPE with age, **drusen** are the specific, organized extracellular deposits pathognomonic for macular degeneration. *Hemosiderine* - **Hemosiderin** is an iron-storage complex formed from the breakdown of hemoglobin, found in situations of hemorrhage or chronic bleeding. - It is not a typical deposit found in macular degeneration; its presence in the retina usually indicates a history of retinal hemorrhage.

Q: Which of the following is a centrally acting antihypertensive drug?

Methyldopa. ***Methyldopa*** - **Methyldopa** is a **prodrug** that is converted to **alpha-methylnorepinephrine** in the brain, which then stimulates **alpha-2 adrenergic receptors** in the brainstem. - This stimulation reduces **sympathetic outflow** from the central nervous system, leading to decreased heart rate, stroke volume, and peripheral vascular resistance, thus lowering blood pressure. *Phenoxybenzamine* - **Phenoxybenzamine** is an **alpha-1 and alpha-2 adrenergic receptor antagonist** (non-selective alpha blocker) that primarily acts peripherally. - It causes **vasodilation** by blocking alpha-1 receptors on smooth muscle, which reduces peripheral vascular resistance. *Propranolol* - **Propranolol** is a **non-selective beta-blocker** that primarily acts on peripheral beta-adrenergic receptors. - It reduces heart rate and cardiac output by blocking **beta-1 receptors** in the heart and can also affect beta-2 receptors in the lungs and vasculature. *Prazosin* - **Prazosin** is a **selective alpha-1 adrenergic receptor antagonist** that acts primarily on peripheral blood vessels. - It causes **vasodilation** in both arteries and veins by blocking alpha-1 receptors, which reduces both preload and afterload, lowering blood pressure.

Q: What are the homes called where children are placed under the care of doctors and psychiatrists?

Residential treatment facilities. ***Residential treatment facilities*** - These facilities provide structured, live-in therapeutic environments where children and adolescents receive comprehensive psychiatric and medical care. - They are staffed by a multidisciplinary team including **psychiatrists**, psychologists, social workers, and nurses. *Foster care homes* - Foster care involves placing children with temporary families, usually due to neglect or abuse, focusing on a family-like setting rather than intensive medical or psychiatric care. - While foster children may receive mental health services, the homes themselves are not clinical environments. *Youth detention centers* - These facilities are for children and adolescents who have committed crimes and are awaiting trial or serving sentences. - While mental health services may be provided, their primary purpose is correctional, not therapeutic. *Child mental health clinics* - These clinics offer outpatient services, including diagnosis, therapy, and medication management, but do not provide residential care. - Children attend appointments and then return home, unlike the live-in care provided in residential facilities.

Question 1

Which disease is most closely associated with intensive international surveillance for global eradication?

Accepted Answer

Polio

Answer

Hepatitis

Answer

TB

Answer

Leprosy

Question 2

Which of the following is not a source of environmental radiation?

Accepted Answer

CO

Answer

Uranium

Answer

Radon

Answer

Radium

Question 3

What does a highly sensitive test imply about its false negative rate?

Accepted Answer

Low false negative rate

Answer

High false positive rate

Answer

High true negative rate

Answer

High true positive rate

Question 4

In the context of epidemiology, what is the denominator used for calculating incidence?

Accepted Answer

Population at risk

Answer

Mid year population

Answer

Total number of cases

Answer

Total number of deaths

Question 5

What is the first external sign of decomposition of a dead body?

Accepted Answer

Greenish discolouration over right iliac fossa

Answer

Decomposition of liver and intestine

Answer

Greenish discolouration over dependent parts

Answer

Blood stained froth from mouth

Question 6

Binding of gp120 causes:

Accepted Answer

Facilitation of co-receptor binding

Answer

Infection of target cell

Answer

Fusing of virus and target cell

Answer

None of the options

Question 7

Who discovered the malarial parasite?

Accepted Answer

Charles Louis Alphonse Laveran

Answer

Ronald Ross

Answer

Paul Muller

Answer

Pampania

Question 8

What type of deposit is commonly associated with age-related macular degeneration?

Accepted Answer

Drusen

Answer

Iron

Answer

Lipochrome

Answer

Hemosiderine

Question 9

Which of the following is a centrally acting antihypertensive drug?

Accepted Answer

Methyldopa

Answer

Phenoxybenzamine

Answer

Propranolol

Answer

Prazosin

Question 10

What are the homes called where children are placed under the care of doctors and psychiatrists?

Accepted Answer

Residential treatment facilities

Answer

Foster care homes

Answer

Youth detention centers

Answer

Child mental health clinics

NEET-PG 2012

Community Medicine

Forensic Medicine

Microbiology

Ophthalmology

Pharmacology

Psychiatry