Biochemistry
1 questionsMark the false statement regarding mitochondrial DNA:
NEET-PG 2019 - Biochemistry NEET-PG Practice Questions and MCQs
Question 211: Mark the false statement regarding mitochondrial DNA:
- A. AGA and AGG are stop codons in mitochondrial DNA
- B. Kearns-Sayre Syndrome is a large deletion in mitochondrial DNA
- C. Does not show heteroplasmy (Correct Answer)
- D. 1% of cellular DNA, 13 proteins of respiratory chain
Explanation: ***Does not show heteroplasmy*** - This statement is false because **mitochondrial DNA (mtDNA)** commonly exhibits **heteroplasmy**, meaning the presence of more than one type of mitochondrial genome within a cell or individual. - **Heteroplasmy** arises due to the presence of both normal and mutated mtDNA, which can be passed down from the mother. *AGA and AGG are stop codons in mitochondrial DNA* - This statement is true; in the **universal genetic code**, AGA and AGG code for **arginine**, but in **human mitochondrial DNA**, they serve as **stop codons**. - This is an example of the **differences** in genetic code interpretation between the nuclear genome and the mitochondrial genome. *Kearns-Sayre Syndrome is a large deletion in mitochondrial DNA* - This statement is true; **Kearns-Sayre Syndrome** is a well-known mitochondrial disorder caused by a **large single deletion** in the mitochondrial DNA. - This deletion often leads to chronic progressive **external ophthalmoplegia**, **retinal pigmentary degeneration**, and **cardiac conduction defects**. *1% of cellular DNA, 13 proteins of respiratory chain* - This statement is true; **mitochondrial DNA constitutes** approximately **1% of the total cellular DNA** by mass. - It codes for **13 essential proteins** that are part of the **electron transport chain** (respiratory chain) complexes in the mitochondrion, along with ribosomal RNAs (rRNAs) and transfer RNAs (tRNAs).
Internal Medicine
2 questionsA man who is chronic alcoholic will develop which type of cardiomyopathy?
In type I diabetes, which of the following is the MOST characteristic metabolic change that distinguishes it from type II diabetes:-
NEET-PG 2019 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 211: A man who is chronic alcoholic will develop which type of cardiomyopathy?
- A. Dilated cardiomyopathy (Correct Answer)
- B. Hypertrophic cardiomyopathy
- C. Myocarditis
- D. Pericarditis
Explanation: ***Dilated cardiomyopathy*** - Chronic alcohol abuse is a major cause of **dilated cardiomyopathy**, where the heart's pumping chambers (ventricles) become enlarged and weakened, leading to reduced cardiac output [1]. - This condition often called **alcoholic cardiomyopathy**, is characterized by **ventricular dilation** and **systolic dysfunction**. *Hypertrophic cardiomyopathy* - This condition involves thickening of the heart muscle, often genetic, and is not directly caused by **chronic alcoholism**. - While alcohol can worsen pre-existing heart conditions, it does not typically lead to primary **hypertrophic cardiomyopathy**. *Myocarditis* - **Myocarditis** is an inflammation of the heart muscle, usually caused by viral infections or autoimmune processes. - Although heavy alcohol use can weaken the immune system, it is not a direct cause of viral or primary inflammatory myocarditis. *Pericarditis* - **Pericarditis** is the inflammation of the pericardium, the sac surrounding the heart, most commonly due to viral infections or autoimmune conditions. - While alcohol abuse can have various systemic effects, it is not a recognized direct cause of **pericarditis**.
Question 212: In type I diabetes, which of the following is the MOST characteristic metabolic change that distinguishes it from type II diabetes:-
- A. Increased protein catabolism
- B. Decreased glucose uptake
- C. Increased hepatic glucose output
- D. Increased lipolysis (Correct Answer)
Explanation: ***Increased lipolysis*** - In **type 1 diabetes** (T1D), there is an **absolute deficiency of insulin**, which is a potent **anti-lipolytic hormone**. [1] - This lack of insulin leads to unopposed **lipolysis**, resulting in increased free fatty acid (FFA) release, which can be metabolized into **ketone bodies** and contribute to **diabetic ketoacidosis (DKA)**. [2] *Increased protein catabolism* - While protein catabolism is increased in uncontrolled T1D due to the lack of insulin and increased counter-regulatory hormones, it is not the *most characteristic* metabolic change that clearly distinguishes it from type 2 diabetes (T2D), especially in early stages of T2D where some insulin may still be present. [1] - **Protein breakdown** produces amino acids for gluconeogenesis, contributing to hyperglycemia, but **lipolysis leading to ketosis** is more specific to severe insulin deficiency. [3] *Decreased glucose uptake* - **Decreased glucose uptake** by peripheral tissues (especially muscle and adipose tissue) is a characteristic feature of both T1D and T2D. [1] - In T1D, it's due to insulin deficiency, while in T2D, it's primarily caused by **insulin resistance**, making it less specific to distinguish T1D. *Increased hepatic glucose output* - **Increased hepatic glucose output** is a significant contributor to hyperglycemia in both T1D and T2D. [1] - In T1D, it's due to the lack of insulin's suppressive effect on the liver, whereas in T2D, it's due to **hepatic insulin resistance** and increased gluconeogenesis.
Microbiology
1 questionsA 9 years old child presented to OPD with complaints of high grade fever, vomiting, one episode of seizure. CSF examination was done and Gram staining of the culture showed the following finding. What is the probable causative agent?
NEET-PG 2019 - Microbiology NEET-PG Practice Questions and MCQs
Question 211: A 9 years old child presented to OPD with complaints of high grade fever, vomiting, one episode of seizure. CSF examination was done and Gram staining of the culture showed the following finding. What is the probable causative agent?
- A. Gram-negative coccobacilli (e.g., Haemophilus influenzae)
- B. Gram-negative diplococci (e.g., Neisseria meningitidis)
- C. Gram-positive diplococci (e.g., Streptococcus pneumoniae) (Correct Answer)
- D. Gram-positive cocci in chains (e.g., Streptococcus pyogenes)
Explanation: ***Gram-positive diplococci (e.g., Streptococcus pneumoniae)*** - The image displays small, purple (Gram-positive) cocci arranged in pairs (**diplococci**). - *Streptococcus pneumoniae* is a common cause of **bacterial meningitis** in children, and its characteristic morphology on Gram stain is Gram-positive diplococci. *Gram-negative coccobacilli (e.g., Haemophilus influenzae)* - While *Haemophilus influenzae* can cause meningitis in children, its Gram stain morphology would show **pink-stained coccobacillary forms**, not purple cocci. - The bacteria in the image are clearly cocci, not coccobacilli, and stain Gram-positive (purple). *Gram-negative diplococci (e.g., Neisseria meningitidis)* - *Neisseria meningitidis* is a significant cause of meningitis and appears as **Gram-negative (pink) diplococci**. - The organisms in the image are stained purple, indicating they are Gram-positive. *Gram-positive cocci in chains (e.g., Streptococcus pyogenes)* - *Streptococcus pyogenes* typically forms **chains of Gram-positive cocci**, which is not the predominant arrangement seen in the image. - Although it is Gram-positive, the characteristic arrangement in the image is diplococci, not chains.
Pediatrics
2 questionsWhich of the following is most specific for congenital Rubella syndrome?
Bilateral grasp is seen at what age?
NEET-PG 2019 - Pediatrics NEET-PG Practice Questions and MCQs
Question 211: Which of the following is most specific for congenital Rubella syndrome?
- A. Blueberry muffin rash is seen
- B. Triad of CRS are cataract, cardiac defects, sensorineural deafness (Correct Answer)
- C. Infection is most serious in the first trimester of pregnancy
- D. Virus can be isolated up to 12 months after birth
Explanation: ***Triad of CRS are cataract, cardiac defects, sensorineural deafness*** - The **classic Gregg triad** of **cataracts**, **cardiac defects** (especially patent ductus arteriosus and pulmonary artery stenosis), and **sensorineural deafness** is the **most specific and pathognomonic** feature of **congenital Rubella syndrome**. - While individual components can occur in other conditions, the **combination of this triad** is highly specific for CRS and distinguishes it from other congenital infections. - This triad was first described by **Norman Gregg** in 1941 and remains the hallmark diagnostic feature of congenital rubella syndrome. *Blueberry muffin rash is seen* - The **blueberry muffin rash** (dermal erythropoiesis) presents as purpuric lesions or small dark blue papules and can be seen in congenital rubella syndrome. - However, this finding is **NOT specific to rubella** and occurs in multiple congenital infections including **CMV, toxoplasmosis, parvovirus B19**, and can also be seen in neonatal malignancies like neuroblastoma. - While characteristic, it is less specific than the Gregg triad for diagnosing CRS. *Infection is most serious in the first trimester of pregnancy* - Maternal rubella infection during the **first trimester** carries the highest risk (up to 85% if infected before 12 weeks) of severe multi-organ abnormalities due to rapid organogenesis. - While true, this describes the **timing and severity** of infection rather than a specific clinical feature that distinguishes rubella from other congenital infections. - Many congenital infections (CMV, toxoplasmosis, HSV) are also more severe when acquired in early pregnancy. *Virus can be isolated up to 12 months after birth* - Infants with **congenital Rubella syndrome** can shed virus in bodily fluids (urine, nasopharyngeal secretions) for **12 months or longer** after birth. - This prolonged viral shedding is important for **infection control** and isolation precautions but is a virological characteristic rather than a specific diagnostic clinical feature. - Other congenital infections (CMV) can also demonstrate prolonged viral shedding in infants.
Question 212: Bilateral grasp is seen at what age?
- A. 6 months
- B. 3 months
- C. 9 months
- D. 5 months (Correct Answer)
Explanation: ***5 months*** - At **5 months**, infants typically develop the ability to **reach for and grasp objects with both hands**, demonstrating improved coordination and control. - This age marks a transition from reflexive grasping to more intentional and bilateral manipulation of objects. *6 months* - While fine motor skills continue to develop at 6 months, **bilateral grasp** is usually well-established by this age, having emerged earlier. - At 6 months, infants are often progressing towards **unilateral grasp** and transferring objects between hands. *3 months* - At **3 months**, infants are typically still developing head control and beginning to reach, but their grasp is often still a **reflexive palmar grasp** rather than intentional bilateral grasping. - Reaching at this age is usually more swiping or batting at objects rather than a coordinated grasp. *9 months* - By **9 months**, infants have developed more refined pincer grasp and are capable of complex manipulation of objects with a single hand. - **Bilateral grasp** is a much earlier developmental milestone than the advanced skills seen at 9 months.
Pharmacology
2 questionsWhich of the following is the first line drug for mastitis?
DOC for prophylaxis against Diphtheria is:-
NEET-PG 2019 - Pharmacology NEET-PG Practice Questions and MCQs
Question 211: Which of the following is the first line drug for mastitis?
- A. Cefazolin
- B. Ampicillin
- C. Metronidazole
- D. Cloxacillin (Correct Answer)
Explanation: ***Cloxacillin*** - **Cloxacillin** is a penicillinase-resistant penicillin, making it effective against **Staphylococcus aureus**, the most common causative organism of mastitis. - It is the **first-line oral antibiotic** for treating mastitis in patients without penicillin allergy. - As a penicillin derivative, it should be **avoided in penicillin-allergic patients**, who may be treated with cephalosporins (if no cross-reactivity) or macrolides instead. *Cefazolin* - **Cefazolin** is a first-generation cephalosporin, typically administered intravenously. While effective against methicillin-sensitive *S. aureus*, it is not the first-line oral treatment for mastitis. - It is usually reserved for hospitalized patients or those needing parenteral therapy, not for initial outpatient management. *Ampicillin* - **Ampicillin** is a penicillin antibiotic that is susceptible to degradation by beta-lactamases produced by many *Staphylococcus aureus* strains. - It is generally **not effective** against beta-lactamase-producing *S. aureus*, which is the predominant pathogen in mastitis. *Metronidazole* - **Metronidazole** is an antibiotic primarily effective against **anaerobic bacteria** and certain **parasites**. - It has **no significant activity** against aerobic bacteria like *Staphylococcus aureus*, making it inappropriate for treating typical bacterial mastitis.
Question 212: DOC for prophylaxis against Diphtheria is:-
- A. Cloxacillin
- B. Rifampicin
- C. Ciprofloxacin
- D. Erythromycin (Correct Answer)
Explanation: ***Erythromycin*** - **Erythromycin** is the drug of choice for prophylaxis and treatment of diphtheria, especially in individuals exposed to a confirmed case. - It works by inhibiting protein synthesis in *Corynebacterium diphtheriae*, preventing bacterial multiplication and toxin production. *Cloxacillin* - **Cloxacillin** is a narrow-spectrum penicillinase-resistant penicillin primarily used for treating staphylococcal infections. - It is not effective against *Corynebacterium diphtheriae* and therefore not used for diphtheria prophylaxis. *Rifampicin* - **Rifampicin** is an antibiotic commonly used for tuberculosis and prophylaxis against meningococcal disease. - It does not have significant activity against *Corynebacterium diphtheriae* and is not indicated for diphtheria prevention. *Ciprofloxacin* - **Ciprofloxacin** is a fluoroquinolone antibiotic with a broad spectrum of activity against many bacterial infections. - While it can be used for some respiratory infections, it is not the recommended antibiotic for diphtheria prophylaxis.
Physiology
2 questionsWhich one of the following is a function of PGI2?
Which of the following is false as physiological change in pregnancy?
NEET-PG 2019 - Physiology NEET-PG Practice Questions and MCQs
Question 211: Which one of the following is a function of PGI2?
- A. Causes blood vessel constriction and prevents platelet clumping
- B. Causes blood vessel constriction and promotes platelet clumping
- C. Causes blood vessel relaxation and prevents platelet clumping (Correct Answer)
- D. Causes blood vessel relaxation and promotes platelet clumping
Explanation: **Correct Answer: Causes blood vessel relaxation and prevents platelet clumping** ***PGI2 (prostacyclin)*** is a potent **vasodilator** produced by vascular endothelium that causes blood vessel relaxation. It also has a powerful inhibitory effect on **platelet aggregation**, thus preventing platelet clumping and thrombosis. These two functions make PGI2 an important anti-thrombotic mediator in the cardiovascular system. *Incorrect: Causes blood vessel constriction and prevents platelet clumping* - This option is incorrect because PGI2 **relaxes blood vessels** (vasodilation), it does not constrict them. - While it correctly states that PGI2 prevents platelet clumping, its effect on blood vessels is wrongly stated. *Incorrect: Causes blood vessel constriction and promotes platelet clumping* - This statement is entirely incorrect as PGI2's functions are the opposite: **vasodilation** and **inhibition of platelet aggregation**. - **Thromboxane A2 (TXA2)** is an eicosanoid with these described effects (constricts blood vessels and promotes platelet clumping), making it the functional antagonist of PGI2. *Incorrect: Causes blood vessel relaxation and promotes platelet clumping* - While PGI2 does cause **blood vessel relaxation** (vasodilation), it actively **prevents platelet clumping** rather than promoting it. - Promotion of platelet clumping is a function of other substances like **Thromboxane A2 (TXA2)**.
Question 212: Which of the following is false as physiological change in pregnancy?
- A. Increase GFR
- B. Increase total protein (Correct Answer)
- C. Increase cardiac output
- D. Increase plasma volume
Explanation: ***Increase total protein*** - During pregnancy, **plasma volume increases disproportionately more than the increase in red blood cell mass**, leading to hemodilution. - This hemodilution results in a **decrease in the concentration of total plasma proteins and albumin**, making this statement false. *Increase GFR* - **Glomerular filtration rate (GFR) increases significantly** during pregnancy (by 30-50%) due to increased renal plasma flow. - This physiological adaptation helps to clear the increased metabolic waste products produced by both the mother and the fetus. *Increase cardiac output* - **Cardiac output increases by 30-50%** during pregnancy, primarily due to increases in both heart rate and stroke volume. - This increased cardiac output ensures adequate blood supply to the uterus, placenta, and other maternal organs. *Increase plasma volume* - **Plasma volume increases substantially (up to 40-50%)** during pregnancy, starting in the first trimester and continuing until term. - This expansion of plasma volume is crucial for meeting the increased circulatory demands of pregnancy and supporting placental perfusion.