NEET-PG 2015 Practice Questions

Q: Which of the following statements about adiponectin is incorrect?

Positive Correlation with BMI. ***Positive Correlation with BMI (INCORRECT STATEMENT)*** - Adiponectin levels are **inversely correlated with BMI**, NOT positively correlated; as BMI increases, adiponectin levels generally decrease. - This inverse relationship is significant because lower adiponectin levels are associated with increased insulin resistance and **metabolic syndrome**. - This statement is **false**, making it the correct answer to this question. *Secreted by adipose tissue (Correct statement)* - Adiponectin is a **hormone primarily secreted by adipocytes** (fat cells). - It plays a crucial role in regulating glucose and lipid metabolism, and its secretion is altered in conditions like obesity. - This statement is **true**. *Lowers glucose (Correct statement)* - Adiponectin **enhances insulin sensitivity** in peripheral tissues like skeletal muscle and liver, leading to increased glucose uptake and utilization. - This action helps to **lower blood glucose levels** and improve glycemic control. - This statement is **true**. *Increases FFA oxidation (Correct statement)* - Adiponectin **promotes fatty acid oxidation** in muscle and liver, reducing intracellular lipid accumulation. - By increasing fatty acid burning, it helps to **decrease circulating free fatty acid (FFA) levels**, which can contribute to insulin resistance if elevated. - This statement is **true**.

Q: In the malate shuttle, how many ATPs are produced from one NADH?

2.5 ATP. ***2.5 ATP*** - In the **malate-aspartate shuttle**, mitochondrial **NADH** is regenerated from cytosolic NADH, and then enters the electron transport chain at **Complex I**. - **Complex I** entry means that NADH contributes to the pumping of enough protons to generate approximately **2.5 ATP** through oxidative phosphorylation. *1 ATP* - **1 ATP** is not the direct equivalent produced from the reoxidation of one NADH via the malate shuttle into the electron transport chain. - This value is typically associated with the direct hydrolysis of **ATP** or the energy equivalent of **GTP** produced in the citric acid cycle. *3 ATP* - Historically, **3 ATP** was the accepted stoichiometry for one NADH, but more accurate measurements of proton pumping and ATP synthase activity have revised this. - The value of 3 ATP per NADH does not reflect the most current understanding of mitochondrial bioenergetics. *2 ATP* - **2 ATP** is the approximate yield for **FADH2** entering the electron transport chain at **Complex II**, bypassing Complex I, and thus pumping fewer protons. - This value is not applicable to NADH transferred via the malate-aspartate shuttle, as NADH enters at Complex I.

Q: Which drug is contraindicated before delivery of the baby (during first and second stages of labor)?

Ergometrine. ***Ergometrine*** - **Ergometrine** is a potent uterotonic agent that causes **tetanic (sustained) uterine contractions**. - It is **absolutely contraindicated before delivery of the baby** (during first and second stages of labor) because: - Sustained contractions lead to **fetal hypoxia** and **fetal distress** by reducing placental blood flow - Risk of **uterine rupture** due to excessive uterine tone - **Obstructed labor** and **cervical lacerations** from forcing delivery against sustained contraction - Ergometrine is **only used after delivery of the baby** in the third stage for active management and prevention of postpartum hemorrhage. *Mifepristone* - **Mifepristone** is an antiprogesterone used for medical abortion in early pregnancy or cervical ripening before labor induction. - It is not relevant during active labor as it acts by blocking progesterone receptors, not by causing immediate uterine contractions. *Oxytocin* - **Oxytocin** is the drug of choice for induction and augmentation of labor. - It causes **rhythmic, intermittent contractions** that allow for adequate placental perfusion between contractions. - Safe to use during first and second stages when properly monitored. *Misoprostol* - **Misoprostol** is a prostaglandin E1 analog used for cervical ripening and labor induction. - Can be used before and during labor for induction, though requires careful monitoring. - Unlike ergometrine, it does not cause sustained tetanic contractions when used in appropriate doses.

Q: At which receptor is the primary action of antipsychotic medications required?

D2 dopaminergic. ***D2 dopaminergic*** - The **antipsychotic effects** of typical (first-generation) antipsychotics are primarily mediated through **D2 receptor blockade** [1]. - Blocking D2 receptors in the **mesolimbic pathway** helps reduce positive symptoms of psychosis like hallucinations and delusions [2]. *M, muscarinic* - **Muscarinic receptor blockade** is a common adverse effect of some antipsychotics, leading to anticholinergic side effects such as **dry mouth** and **blurred vision**, rather than their primary therapeutic action. - This action does not directly contribute to the antipsychotic effect. *D1 dopaminergic* - While D1 receptors are involved in dopamine signaling, they are **not the primary target** for the antipsychotic action of most drugs [1]. - Some atypical antipsychotics may affect D1 receptors, but it's secondary to their D2 antagonism and serotonin modulation. *5HT4 serotonergic* - **Serotonin receptors (5HT)**, particularly 5HT2A, are important targets for atypical (second-generation) antipsychotics. - However, 5HT4 receptors are **not a primary target** for the antipsychotic effects, and 5HT2A blockade modulates dopamine release, which is still connected to the D2 hypothesis.

Q: What is the classification of Lorcaserin?

Anti-obesity. ***Anti-obesity*** - Lorcaserin is a selective **serotonin 5-HT₂C receptor agonist** that works by promoting satiety and reducing food intake. - It is prescribed as a long-term treatment for **weight management** in adults who are obese or overweight with at least one weight-related comorbidity. *Anti-anxiety* - Anti-anxiety medications, such as **benzodiazepines** or **SSRIs**, primarily target neurotransmitters like GABA or serotonin 5-HT₁A receptors to reduce anxiety symptoms. - Lorcaserin's primary mechanism of action is distinct, focusing on the 5-HT₂C receptor for appetite regulation, not anxiety. *Anti-smoking* - Anti-smoking medications, like **varenicline** or **bupropion**, are designed to reduce nicotine cravings and withdrawal symptoms. - Their mechanisms often involve nicotinic acetylcholine receptors or dopamine and norepinephrine reuptake inhibition, which differs from lorcaserin's action. *Anti-helminthic* - Anti-helminthic drugs are used to treat **parasitic worm infections** by paralyzing or killing the worms. - Common examples include **albendazole** or **mebendazole**, which have no relation to appetite control or obesity treatment.

Q: How do thiazides cause hypercalcemia?

Decreased calcium excretion. ***Decreased calcium excretion*** - Thiazides inhibit the **Na-Cl co-transporter** in the **distal convoluted tubule**, leading to increased reabsorption of calcium [1], [2]. - This increased reabsorption of calcium is mediated by a low intracellular sodium concentration, which enhances the activity of the **Na+/Ca2+ exchanger** on the basolateral membrane [1]. *Increased parathyroid hormone secretion* - Thiazides **do not directly stimulate** parathyroid hormone (PTH) secretion; instead, they *decrease* calcium excretion, which would typically *lower* PTH levels through negative feedback. - Elevated PTH would lead to increased bone resorption and kidney calcium reabsorption, but this is not the **primary mechanism** for thiazide-induced hypercalcemia [2]. *Decreased calcitonin secretion* - **Calcitonin** is a hormone that *lowers* blood calcium levels, and its decrease would theoretically contribute to hypercalcemia. - However, thiazides have **no direct effect** on calcitonin secretion, making this an unlikely primary mechanism. *Increased calcium absorption* - While increased calcium absorption from the gut can contribute to hypercalcemia, thiazides do **not directly increase intestinal calcium absorption**. - Their primary action for influencing calcium levels is within the **kidney**, specifically on reabsorption, not absorption from the GI tract [1], [2].

Q: Flu-like symptoms are a side effect of which anti-TB drug?

Rifampicin. ***Rifampicin*** - **Flu-like syndrome** (fever, chills, myalgia, and headache) is a dose-dependent side effect of **rifampicin**, particularly with intermittent dosing. - This reaction is due to **immunological mechanisms**, involving antibodies against rifampicin. *Isoniazid* - The most significant side effect of isoniazid is **hepatotoxicity**, which can range from mild elevated liver enzymes to severe hepatitis. - It can also cause **peripheral neuropathy**, particularly in malnourished patients or those with risk factors, preventable with pyridoxine (vitamin B6) supplementation. *Pyrazinamide* - **Hepatotoxicity** is a major concern with pyrazinamide, often leading to elevated liver enzymes and, in some cases, severe liver damage. - It frequently causes **hyperuricemia**, which can precipitate acute gouty arthritis due to decreased excretion of uric acid. *Ethambutol* - The most characteristic adverse effect of ethambutol is **optic neuritis**, causing decreased visual acuity, red-green color blindness, and visual field defects. - Regular **ophthalmological monitoring** is crucial during treatment to detect this reversible side effect early.

Q: Acrosome reaction is seen in?

Fertilization. ***Fertilization*** - The **acrosome reaction** is a crucial event that occurs when a **spermatozoon** comes into contact with the **zona pellucida** surrounding the oocyte. - This reaction involves the release of **hydrolytic enzymes** from the acrosome, which are essential for the sperm to penetrate the zona pellucida and fuse with the oocyte membrane. *Spermatogenesis* - **Spermatogenesis** is the process of sperm formation in the testes, involving meiosis and spermiogenesis. - While it produces the sperm cell with an acrosome, the **acrosome reaction itself does not occur** during this developmental stage. *Oogenesis* - **Oogenesis** is the process of egg cell formation in the ovaries. - This process is entirely **separate from sperm function** and does not involve the acrosome or the acrosome reaction. *Menstruation* - **Menstruation** is the monthly shedding of the uterine lining in females when fertilization does not occur. - This process is part of the female reproductive cycle and has **no direct involvement with sperm or the acrosome reaction**.

Q: Vibrations are detected by which types of receptors?

Rapidly adapting. ***Rapidly adapting*** - **Rapidly adapting mechanoreceptors**, such as **Pacinian corpuscles** and **Meissner's corpuscles**, are highly sensitive to changes in pressure and movement. - They fire at the **onset and offset of a stimulus**, making them ideal for detecting vibrations, which are rhythmic changes in pressure. *Slowly adapting* - **Slowly adapting mechanoreceptors**, such as **Merkel cells** and **Ruffini endings**, are responsible for sustained pressure and touch. - They continue to fire as long as the stimulus is present, making them less suited for detecting transient vibratory stimuli. *Non-adapting* - The human body does not typically have **truly non-adapting** sensory receptors; most receptors show some form of adaptation to continuous stimuli. - This term is not standard in the classification of mechanoreceptors based on their adaptation rates. *None of the above* - This option is incorrect because rapidly adapting receptors are indeed responsible for detecting vibrations.

Question 1

Which of the following statements about adiponectin is incorrect?

Accepted Answer

Positive Correlation with BMI

Answer

Secreted by adipose tissue

Answer

Increases FFA oxidation

Answer

Lowers glucose

Question 2

In the malate shuttle, how many ATPs are produced from one NADH?

Accepted Answer

2.5 ATP

Answer

1 ATP

Answer

3 ATP

Answer

2 ATP

Question 3

What is defined as a negative autopsy?

Accepted Answer

No cause of death is found after both gross and histopathological examination.

Answer

Cause is apparent on gross examination but not on histopathological examination.

Answer

Gross findings are minimal.

Answer

Cause is apparent on gross examination but not found due to constraints on the part of the doctor.

Question 4

Which drug is contraindicated before delivery of the baby (during first and second stages of labor)?

Accepted Answer

Ergometrine

Answer

Mifepristone

Answer

Oxytocin

Answer

Misoprostol

Question 5

At which receptor is the primary action of antipsychotic medications required?

Accepted Answer

D2 dopaminergic

Answer

M, muscarinic

Answer

5HT4 serotonergic

Answer

D1 dopaminergic

Question 6

What is the classification of Lorcaserin?

Accepted Answer

Anti-obesity

Answer

Anti-anxiety

Answer

Anti-smoking

Answer

Anti-helminthic

Question 7

How do thiazides cause hypercalcemia?

Accepted Answer

Decreased calcium excretion

Answer

Increased parathyroid hormone secretion

Answer

Decreased calcitonin secretion

Answer

Increased calcium absorption

Question 8

Flu-like symptoms are a side effect of which anti-TB drug?

Accepted Answer

Rifampicin

Answer

Isoniazid

Answer

Pyrazinamide

Answer

Ethambutol

Question 9

Acrosome reaction is seen in?

Accepted Answer

Fertilization

Answer

Spermatogenesis

Answer

Oogenesis

Answer

Menstruation

Question 10

Vibrations are detected by which types of receptors?

Accepted Answer

Rapidly adapting

Answer

Slowly adapting

Answer

Non-adapting

Answer

None of the above

NEET-PG 2015

Biochemistry

Forensic Medicine

Obstetrics and Gynecology

Pharmacology

Physiology