NEET-PG 2020 Practice Questions

Q: Ochronosis is due to the accumulation of?

Homogentisic acid. ***Homogentisic acid (Correct)*** - **Ochronosis** is a rare genetic disorder characterized by the accumulation of **homogentisic acid** in connective tissues. - This accumulation results from a deficiency of the enzyme **homogentisate 1,2-dioxygenase**, which is crucial in the catabolism of tyrosine and phenylalanine. - Clinically presents with dark pigmentation of cartilage, sclera, and other connective tissues. *Alkapton (Incorrect)* - While **alkaptonuria** is the disease caused by homogentisic acid accumulation, **alkapton** itself is not the substance that accumulates in tissues in ochronosis. - **Alkapton** refers to the dark-colored urine observed in patients with alkaptonuria, which is due to the oxidation of homogentisic acid in the urine. *Xanthurenate (Incorrect)* - **Xanthurenate** is an intermediate in the metabolism of tryptophan, and its accumulation is associated with certain vitamin B6 deficiencies. - It is not involved in the pathogenesis of ochronosis or alkaptonuria. *Glyoxylate (Incorrect)* - **Glyoxylate** is a metabolic intermediate involved in various pathways, including carbohydrate and amino acid metabolism. - Accumulation of glyoxylate is associated with **primary hyperoxaluria type 1**, but not with ochronosis.

Q: What is the appropriate color for containers used to dispose of chemical liquid biomedical waste?

Yellow container. ***Yellow container*** - **Yellow containers** are specifically designated for disposal of **chemical liquid biomedical waste** as per BMW Management Rules, 2016. - This includes **disinfectants, chemical waste from laboratories, discarded medicines, and cytotoxic drugs**. - Yellow containers are used for Category 10 waste (Chemical Waste) which comprises chemicals used in production of biologicals, chemicals used in disinfection, and chemical liquid waste. - This waste typically requires **incineration or plasma pyrolysis** for safe disposal. *White/Translucent container* - **White or translucent containers** are used for **sharp waste** including needles, syringes with fixed needles, scalpels, blades, and contaminated broken glass. - This is Category 4 waste under BMW Rules and requires autoclaving or dry heat sterilization followed by shredding or mutilation. - These containers are puncture-proof and leak-proof to prevent needle-stick injuries. *Blue container* - **Blue containers** are designated for **glassware and metallic body implants** that can be recycled after proper disinfection. - This includes broken or unbroken glass vials (without chemical contamination), ampoules, and other glass items. - Also used for disposal of metallic implants removed during surgeries. *Red container* - **Red containers** are used for **contaminated recyclable plastic waste** including tubing, bottles, IV sets without needles, catheters, and urine bags. - This is Category 3 waste which requires autoclaving or microwaving followed by shredding before recycling. - Helps in waste segregation for potential recycling of plastic materials.

Q: A 30-year-old male presents with a one-week history of severe toothache, swelling in the floor of the mouth, and difficulty swallowing. What is the most likely diagnosis?

Ludwig's angina. ***Ludwig's angina*** - The combination of a recent **severe toothache** (suggesting odontogenic infection), **swelling in the floor of the mouth**, and **difficulty swallowing (dysphagia)** are classic signs of Ludwig's angina, a rapidly spreading cellulitis of the submandibular, sublingual, and submental spaces. - This condition is particularly dangerous due to its potential to cause **airway obstruction** if the swelling progresses posteriorly. *Acute parotitis* - Acute parotitis typically presents with swelling and pain primarily in the **parotid gland region**, often located anterior to the ear and extending to the angle of the jaw. - While it can cause pain and difficulty swallowing, swelling is not typically described as being predominantly in the **floor of the mouth**. *Angioneurotic edema* - Angioneurotic edema (or angioedema) is characterized by **rapid, localized swelling of subcutaneous or submucosal tissues**, often affecting the face, lips, tongue, and pharynx. - It usually lacks a preceding infectious etiology like a toothache and is typically attributed to allergic reactions or hereditary/acquired deficiencies in C1-esterase inhibitor. *Parapharyngeal abscess* - A parapharyngeal abscess is a deep neck infection located in the **parapharyngeal space** lateral to the pharynx, often presenting with fever, severe sore throat, and trismus (difficulty opening the mouth). - While it can cause dysphagia and neck swelling, the primary swelling location described in the **floor of the mouth** points away from a parapharyngeal abscess as the most likely diagnosis.

Q: Renal tubular acidosis with ABG value pH = 7.24 PO2=80; PaCO2= 36 Na = 131; HCO3 = 14 Cl= 90; BE = -13 Glucose = 135 the above ABG picture suggests –

Metabolic acidosis. The ABG shows a pH of 7.24, indicating **acidemia** [1]. The HCO3 is 14 mEq/L, which is significantly **low**, and the base excess (BE) is -13 [1]. The PaCO2 of 36 mmHg is within the normal range, indicating no significant primary respiratory derangement [2]. The overall picture is consistent with an uncompensated or partially compensated **metabolic acidosis** [1][2]. ***Metabolic acidosis*** - The **low pH (acidemia)**, **low bicarbonate (HCO3)**, and **negative base excess (BE)** are direct indicators of metabolic acidosis [1]. - The **PaCO2 within normal limits** or slightly decreased suggests either no respiratory compensation or insufficient compensation for the metabolic derangement [1][2]. *Respiratory acidosis* - This would present with a **low pH** and an **elevated PaCO2** as the primary defect, which is not seen here (PaCO2 is normal) [1]. - Bicarbonate would typically be normal or elevated if compensated, not significantly decreased. *Respiratory alkalosis* - This would be characterized by an **elevated pH** and a **low PaCO2**, which is the opposite of the findings in this ABG [1]. - HCO3 would be normal or low if compensated. *Metabolic alkalosis* - This would present with an **elevated pH** and an **elevated HCO3**, which contradicts the given ABG values (low pH and low HCO3) [2].

Q: A 15-year-old boy presented with fever and chills for 3 days. On examination, he was found to have delayed skin pinch time and dry oral mucosa. Identify the pathogen involved based on the provided peripheral blood smear image.

Plasmodium vivax. ***Plasmodium vivax*** - The image shows **enlarged red blood cells** infected with various stages of *Plasmodium vivax*, including trophozoites and schizonts displaying **ameboid forms**. - The presence of **Schüffner's dots**, though not distinctly visible in this specific resolution, is characteristic of *P. vivax* infection. - *P. vivax* preferentially infects **reticulocytes** and young red blood cells, leading to the characteristic RBC enlargement. *Babesia* - *Babesia* infection typically presents with **ring forms** in red blood cells that lack pigment and often form **tetrads** (Maltese cross appearance), which are not seen here. - While it can cause fever and chills, the morphology of the parasites in the image is inconsistent with *Babesia*. *Plasmodium falciparum* - *P. falciparum* characteristically presents with **multiple small ring forms** in a single red blood cell and **crescent-shaped gametocytes**. - It infects red blood cells of all ages, does not typically enlarge the red blood cells, and early trophozoites (*ring forms*) are the most common stage seen in peripheral blood, which differs from the image. *Salmonella typhi* - *Salmonella typhi* is a bacterium that causes **typhoid fever** and is a systemic infection. - It does not infect red blood cells or present with intraerythrocytic parasites on a peripheral blood smear; diagnosis is typically made by **blood culture**.

Q: A mother brought her 16-year-old daughter to Gynaecology OPD with a complaint of not attaining menarche. She gives a history of cyclic abdominal pain. On further examination, a midline abdominal swelling is seen. Per rectal examination reveals a bulging mass in the vagina. Which of the following conditions is most likely responsible for these findings?

Imperforate hymen. ***Imperforate hymen*** - An **imperforate hymen** obstructs the outflow of menstrual blood, leading to its accumulation in the vagina (**hematocolpos**) and uterus (**hematometra**), causing **cyclic abdominal pain** and a bulging mass (due to accumulated blood) in the vagina. - The patient presents with **primary amenorrhea** (not having attained menarche) and cyclical abdominal pain caused by the inability of menstrual blood to exit the body. *Transverse vaginal septum* - A **transverse vaginal septum** can also cause primary amenorrhea and cyclic abdominal pain due to obstruction of menstrual flow. However, it is a less common cause than an imperforate hymen. - While it can lead to hematocolpos, the characteristic bulging mass on per rectal examination is more strongly associated with an imperforate hymen presenting at the vaginal introitus. *Vaginal agenesis* - **Vaginal agenesis** (complete absence of the vagina) would present with primary amenorrhea, but there would be no cyclic abdominal pain if the uterus is also absent or rudimentary. If a uterus is present, there would be no accumulation of blood in the vagina or a bulging mass per rectum as there is no vaginal canal. - This condition is typically associated with a rudimentary or absent uterus, leading to an inability to menstruate rather than obstructed flow. *Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome* - **MRKH syndrome** is characterized by congenital aplasia of the uterus and the upper two-thirds of the vagina, with normal ovaries and external genitalia. - Patients present with **primary amenorrhea** but typically do not experience **cyclic abdominal pain** or a bulging vaginal mass because there is no functional uterus to produce menstrual blood or a vaginal canal for blood accumulation.

Q: 25-year-old man presents for a routine physical examination. The patient is tall and on examination, he was found to have an early diastolic murmur. His family pedigree is given below (image attached). Which of the following is the mode of inheritance by which the disease is likely to be transmitted?

Autosomal Dominant. ***Autosomal Dominant*** - The pedigree shows that the disease appears in every generation, and affected individuals have at least one affected parent (e.g., I-1 passes it to II-1, II-5, II-8). This pattern is characteristic of **dominant inheritance**. - Both males and females are affected, and affected fathers can pass the trait to their sons (e.g., I-1 to II-1), ruling out X-linked inheritance and supporting an **autosomal dominant** mode. *Autosomal Recessive* - In autosomal recessive inheritance, affected individuals typically have **unaffected parents** (who are carriers), and the disease often skips generations. This is not observed in the provided pedigree. - While both males and females can be affected, the presence of affected individuals in every generation and vertical transmission makes recessive inheritance unlikely. *X-Linked Recessive* - X-linked recessive disorders typically show more affected males than females, and affected fathers **cannot pass the trait to their sons**. The pedigree clearly shows affected females and father-to-son transmission (I-1 to II-1 and potentially II-8 to III-6), ruling out this pattern. - Also, all daughters of an affected father would be carriers, and some an affected mother would have affected offspring. *X-Linked Dominant* - In X-linked dominant inheritance, all daughters of an affected father would be affected, and there is no male-to-male transmission. - The pedigree shows instances where affected fathers (like I-1) have unaffected daughters (e.g., II-2, II-4, II-6, II-7), and affected mothers (II-5, II-8) have unaffected children, which contradicts X-linked dominant inheritance.

Q: Where does meiosis occur in human females?

In the adult ovary. ***In the adult ovary*** - **Meiosis I** in oocytes starts during fetal development but arrests in prophase I. It resumes and completes in the **adult ovary** just before ovulation in response to hormonal signals. - **Meiosis II** begins after the completion of Meiosis I and arrests in metaphase II. It is only completed upon **fertilization** by a sperm, also occurring within the adult reproductive tract. *At birth in the ovary* - At birth, female ovaries contain primary oocytes that have entered **meiosis I** but are arrested in prophase I; actual meiotic divisions promoting maturation do not occur at this stage. - The completion of meiosis I and the initiation of meiosis II are processes that are **post-puberty** and occur in response to hormonal changes leading to ovulation. *In the adult testis* - The testis is the male gonad, and it is the site of **spermatogenesis**, the process of sperm production involving meiosis in males. - **Oogenesis**, the formation of female gametes, occurs exclusively in the **ovaries** of females. *In the prepubertal testis* - In the prepubertal testis, spermatogenesis has not yet begun, and thus **meiosis does not occur** at this stage in males. - Meiosis in males usually begins during **puberty** under the influence of hormones like testosterone.

Q: Cerebral blood flow is regulated by all of the following except:

Calcium ions. ***Calcium ions*** - While **calcium ions (Ca²⁺)** are mechanistically essential for vascular smooth muscle contraction and relaxation, they are **not considered a primary regulatory signal** for cerebral blood flow (CBF) in the same way as the other factors listed. - Ca²⁺ acts as an **intracellular second messenger** that mediates the effects of other regulatory factors (like PCO2, K⁺, and vasoactive substances), rather than being a direct extracellular regulatory signal itself. - The question refers to primary regulatory factors that directly modulate CBF, not the intracellular mechanisms by which vascular smooth muscle responds. *Blood pressure* - **Cerebral autoregulation** maintains relatively constant CBF despite changes in **mean arterial pressure (MAP)** between approximately 60-150 mmHg. - Blood pressure is a **key regulatory factor** - when MAP falls below or exceeds this range, CBF becomes pressure-dependent. - This protective mechanism prevents cerebral ischemia or hyperemia with systemic blood pressure fluctuations. *Arterial PCO2* - **Arterial partial pressure of carbon dioxide (PaCO2)** is one of the **most potent direct regulators** of CBF. - **Hypercapnia** (increased PaCO2) causes cerebral vasodilation and increased CBF (approximately 1-2 mL/100g/min increase per 1 mmHg rise in PaCO2). - **Hypocapnia** (decreased PaCO2) causes vasoconstriction and reduced CBF, utilized therapeutically in managing elevated intracranial pressure. *Potassium ions* - **Increased extracellular K⁺** in the perivascular space causes **direct vasodilation** of cerebral arterioles. - This mechanism is crucial for **neurovascular coupling** (functional hyperemia) - when neurons are active, they release K⁺, which dilates nearby vessels to increase local blood flow. - K⁺-mediated vasodilation helps match cerebral perfusion to metabolic demand during neuronal activity.

Question 1

Ochronosis is due to the accumulation of?

Accepted Answer

Homogentisic acid

Answer

Alkapton

Answer

Xanthurenate

Answer

Glyoxylate

Question 2

What is the appropriate color for containers used to dispose of chemical liquid biomedical waste?

Accepted Answer

Yellow container

Answer

White container

Answer

Blue container

Answer

Red container

Question 3

A 30-year-old male presents with a one-week history of severe toothache, swelling in the floor of the mouth, and difficulty swallowing. What is the most likely diagnosis?

Accepted Answer

Ludwig's angina

Answer

Acute parotitis

Answer

Angioneurotic edema

Answer

Parapharyngeal abscess

Question 4

What is the cause of loss of pain and temperature sensation on the ipsilateral face and contralateral body due to thrombosis?

Accepted Answer

Thrombosis of the posterior inferior cerebellar artery (PICA)

Answer

Thrombosis of the superior cerebellar artery

Answer

Thrombosis of the anterior inferior cerebellar artery (AICA)

Answer

Thrombosis of the posterior cerebral artery

Question 5

Renal tubular acidosis with ABG value pH = 7.24 PO2=80; PaCO2= 36 Na = 131; HCO3 = 14 Cl= 90; BE = -13 Glucose = 135 the above ABG picture suggests –

Accepted Answer

Metabolic acidosis

Answer

Respiratory alkalosis

Answer

Metabolic alkalosis

Answer

Respiratory acidosis

Question 6

A 15-year-old boy presented with fever and chills for 3 days. On examination, he was found to have delayed skin pinch time and dry oral mucosa. Identify the pathogen involved based on the provided peripheral blood smear image.

Accepted Answer

Plasmodium vivax

Answer

Babesia

Answer

Plasmodium falciparum

Answer

Salmonella typhi

Question 7

A mother brought her 16-year-old daughter to Gynaecology OPD with a complaint of not attaining menarche. She gives a history of cyclic abdominal pain. On further examination, a midline abdominal swelling is seen. Per rectal examination reveals a bulging mass in the vagina. Which of the following conditions is most likely responsible for these findings?

Accepted Answer

Imperforate hymen

Answer

Vaginal agenesis

Answer

Transverse vaginal septum

Answer

Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome

Question 8

25-year-old man presents for a routine physical examination. The patient is tall and on examination, he was found to have an early diastolic murmur. His family pedigree is given below (image attached). Which of the following is the mode of inheritance by which the disease is likely to be transmitted?

Accepted Answer

Autosomal Dominant

Answer

Autosomal Recessive

Answer

X-Linked Recessive

Answer

X-Linked Dominant

Question 9

Where does meiosis occur in human females?

Accepted Answer

In the adult ovary

Answer

At birth in the ovary

Answer

In the adult testis

Answer

In the prepubertal testis

Question 10

Cerebral blood flow is regulated by all of the following except:

Accepted Answer

Calcium ions

Answer

Blood pressure

Answer

Arterial PCO2

Answer

Potassium ions

NEET-PG 2020

Biochemistry

Community Medicine

Dental

Internal Medicine

Microbiology

Obstetrics and Gynecology

Pathology

Physiology