Biochemistry
3 questionsWhich of the following statements is true regarding the telomerase theory of aging?
Which of the following helps in the transport of fatty acids across the inner mitochondrial membrane?
An adolescent male patient presents to you with exercise intolerance. He gives a history of developing cramps on exertion. Which of the following enzyme deficiencies could be the cause?
NEET-PG 2022 - Biochemistry NEET-PG Practice Questions and MCQs
Question 21: Which of the following statements is true regarding the telomerase theory of aging?
- A. Decreased telomere length is associated with aging (Correct Answer)
- B. Abnormal telomerase activation is associated with cancer
- C. Telomere stability directly maintains chromosomal integrity
- D. Increased telomere length is associated with prolonged cellular lifespan
Explanation: ***Decreased telomere length is associated with aging*** - Telomeres are protective DNA-protein caps at chromosome ends that **shorten with each cell division** - Progressive telomere shortening triggers **cellular senescence** (Hayflick limit) and apoptosis - This mechanism directly contributes to aging and **age-related diseases** - The telomere theory of aging (Olovnikov hypothesis) states that telomere attrition is a primary driver of biological aging *Abnormal telomerase activation is associated with cancer* - **Telomerase is reactivated in ~85-90% of cancers**, enabling unlimited replicative potential - Normal adult somatic cells have low/absent telomerase activity - While telomerase can extend cellular lifespan, its aberrant activation leads to malignancy, not healthy aging *Telomere stability directly maintains chromosomal integrity* - Telomeres prevent chromosome degradation, end-to-end fusions, and DNA damage responses - This is a **protective function**, not the basis of the telomere theory of aging - The aging theory focuses on **consequences of telomere shortening**, not stability maintenance *Increased telomere length is associated with prolonged cellular lifespan* - Longer telomeres do correlate with younger biological age and extended replicative capacity - However, this describes the **inverse relationship** rather than the core aging theory - The telomere theory specifically explains aging through **progressive shortening**, not length extension
Question 22: Which of the following helps in the transport of fatty acids across the inner mitochondrial membrane?
- A. Acyl carrier protein
- B. Carnitine (Correct Answer)
- C. Lecithin-cholesterol acyltransferase
- D. Carnitine and albumin
Explanation: ***Carnitine*** - **Carnitine** plays a crucial role in transporting long-chain fatty acids from the **cytosol** into the **mitochondrial matrix** for beta-oxidation. - It acts as a shuttling molecule, forming **acylcarnitine** which can cross the inner mitochondrial membrane via the **carnitine-acylcarnitine translocase**. *Acyl carrier protein* - **Acyl carrier protein (ACP)** is primarily involved in **fatty acid synthesis** in the cytoplasm, not in the transport of fatty acids into mitochondria for degradation. - It carries acyl groups during the elongation reactions of fatty acid synthesis. *Lecithin-cholesterol acyltransferase* - **Lecithin-cholesterol acyltransferase (LCAT)** is an enzyme found in plasma that catalyzes the formation of **cholesterol esters**, which are then transported by lipoproteins. - It is involved in **cholesterol metabolism** and reverse cholesterol transport, not in the mitochondrial transport of fatty acids. *Carnitine and albumin* - While **carnitine** is essential for mitochondrial fatty acid transport, **albumin** transports fatty acids in the blood plasma, from adipose tissue to other tissues. - Albumin does not transport fatty acids across the inner mitochondrial membrane; its role is extra-mitochondrial and related to systemic transport.
Question 23: An adolescent male patient presents to you with exercise intolerance. He gives a history of developing cramps on exertion. Which of the following enzyme deficiencies could be the cause?
- A. Myophosphorylase (Correct Answer)
- B. Hexokinase
- C. Glucose-6-phosphatase
- D. Hepatic glycogen phosphorylase
Explanation: ***Myophosphorylase*** - A deficiency in **myophosphorylase** (McArdle's disease, Glycogen Storage Disease Type V) impairs muscle glycogen breakdown, leading to **exercise intolerance** and **muscle cramps** due to insufficient ATP production during exertion. - Patients often experience a "second wind" phenomenon where symptoms improve after resting, as free fatty acids become an alternative fuel source. *Hexokinase* - A deficiency in **hexokinase** would affect the first step of glycolysis, impacting glucose phosphorylation in all tissues, not specifically causing exercise-induced muscle cramps. - This deficiency is rare and typically presents with **hemolytic anemia** due to impaired erythrocyte metabolism. *Glucose-6-phosphatase* - A deficiency in **glucose-6-phosphatase** (Von Gierke's disease, Glycogen Storage Disease Type Ia) primarily affects the liver and kidneys, leading to **fasting hypoglycemia**, lactic acidosis, and hepatomegaly, not exercise intolerance. - Muscle glycogen metabolism is unaffected in this condition. *Hepatic glycogen phosphorylase* - A deficiency in **hepatic glycogen phosphorylase** (Hers' disease, Glycogen Storage Disease Type VI) mainly causes **hepatomegaly** and **mild hypoglycemia** because the liver cannot effectively mobilize its glycogen stores. - **Muscle glycogen metabolism** remains normal, so exercise intolerance and cramps are not characteristic symptoms.
Internal Medicine
3 questionsWhich one of the following is an autosomal recessive disorder?
A patient presents to you with an irregularly irregular pulse of 120/minutes and a pulse deficit of 20. Which of the following would be the jugular venous pressure (JVP) finding?
Which of the following is not seen in MEN 2B syndrome?
NEET-PG 2022 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 21: Which one of the following is an autosomal recessive disorder?
- A. Cystic fibrosis (Correct Answer)
- B. Huntington's disease
- C. Marfan syndrome
- D. Neurofibromatosis type 1
Explanation: ***Cystic fibrosis*** - **Cystic fibrosis** is caused by mutations in the **CFTR gene**, leading to defective **chloride channel** function. - It is an **autosomal recessive disorder**, meaning an individual must inherit two copies of the mutated gene (one from each parent) to be affected. *Huntington's disease* - **Huntington's disease** is an **autosomal dominant disorder** caused by a mutation in the HTT gene. - Only one copy of the mutated gene is sufficient to cause the disease, resulting in progressive neurodegeneration. *Marfan syndrome* - **Marfan syndrome** is an **autosomal dominant disorder** affecting connective tissue, caused by mutations in the FBN1 gene. - It results in skeletal, ocular, and cardiovascular abnormalities due to defective **fibrillin-1**. *Neurofibromatosis type 1* - **Neurofibromatosis type 1** is an **autosomal dominant disorder** caused by mutations in the NF1 gene. - It is characterized by multiple neurofibromas, café-au-lait macules, and Lisch nodules.
Question 22: A patient presents to you with an irregularly irregular pulse of 120/minutes and a pulse deficit of 20. Which of the following would be the jugular venous pressure (JVP) finding?
- A. Normal JVP
- B. Absent a wave (Correct Answer)
- C. Cannon a wave
- D. Raised JVP with normal waveform
Explanation: ***Absent a wave*** - An **irregularly irregular pulse** with a **pulse deficit** strongly suggests **atrial fibrillation (AF)**. - In AF, the atria quiver chaotically instead of contracting effectively, leading to the **absence of a coordinated atrial contraction** and thus an **absent 'a' wave** in the JVP. *Normal JVP* - A normal JVP would show a regular **'a' wave** corresponding to normal atrial contraction. - This is inconsistent with the **irregularly irregular pulse** and **pulse deficit** seen in the patient, which points to a significant atrial arrhythmia. *Cannon a wave* - A **cannon 'a' wave** results from the right atrium contracting against a closed tricuspid valve, leading to a large, prominent wave in the JVP. - This is typically seen in conditions like **complete heart block** or **ventricular tachycardia with AV dissociation**, not atrial fibrillation. *Raised JVP with normal waveform* - A raised JVP with a normal waveform indicates increased right atrial pressure but preserves the normal sequence of atrial contraction and relaxation. - This could be due to conditions like **right heart failure** or **volume overload**, but would still show the presence of an 'a' wave, which is absent in atrial fibrillation.
Question 23: Which of the following is not seen in MEN 2B syndrome?
- A. Mucosal neuroma
- B. Marfanoid habitus
- C. Parathyroid adenoma (Correct Answer)
- D. Megacolon
Explanation: ***Parathyroid adenoma*** - **Parathyroid adenomas**, leading to hyperparathyroidism, are characteristic of **MEN 2A syndrome**, not MEN 2B [1]. - While both MEN 2A and 2B involve mutations in the **RET proto-oncogene**, the specific clinical manifestations differ significantly. *Megacolon* - **Megacolon** (due to intestinal ganglioneuromatosis) is a recognized feature of **MEN 2B syndrome**. - This condition involves abnormal nerve ganglion cells in the intestine, leading to motility issues. *Mucosal neuroma* - **Mucosal neuromas** on the tongue, lips, and eyelids are a hallmark clinical sign of **MEN 2B syndrome**. - These benign growths are often one of the earliest and most recognizable features. *Marfanoid habitus* - **Marfanoid habitus**, characterized by a tall, slender build with long limbs and arachnodactyly, is a common physical finding in **MEN 2B syndrome**. - This connective tissue abnormality helps distinguish MEN 2B from other MEN syndromes.
Obstetrics and Gynecology
3 questionsA 24 year old lactating female with an 18 month old child comes with a history of irregular, heavy bleeding seeking contraceptive advice. Which is the contraceptive of choice?
A pregnant patient, with a history of classical cesarean section in view of fetal growth retardation in the previous pregnancy, presents to you. She is currently at 35 weeks of gestation with breech presentation. What is the next step in management?
A woman with an obstetric score of G2P1 comes to the clinic at 14 weeks of gestation for her antenatal checkup. A uterine artery doppler was suggested by the doctor. What would it detect?
NEET-PG 2022 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 21: A 24 year old lactating female with an 18 month old child comes with a history of irregular, heavy bleeding seeking contraceptive advice. Which is the contraceptive of choice?
- A. Progestin-only pill (Correct Answer)
- B. Copper IUD
- C. Progestin-only injection
- D. Combined oral contraceptive pill
Explanation: ***Progestin-only pill*** - The **progestin-only pill (POP)** is the contraceptive of choice for lactating women because it does not affect **breast milk supply** or composition. - It works by thickening cervical mucus and thinning the **endometrium**, which can help reduce heavy bleeding and provide effective contraception. *Copper IUD* - While the **copper IUD** is a highly effective contraceptive, it is known to potentially increase **menstrual bleeding** and cramping. - Given the patient's history of **heavy bleeding**, a copper IUD might worsen her symptoms. *Progestin-only injection* - **Progestin-only injections** like DMPA are highly effective and safe for lactating women, but they can cause **irregular bleeding patterns** initially and are associated with a slower return to fertility. - While an option, the **progestin-only pill** offers more immediate control over menstrual patterns and easier discontinuation if side effects are problematic. *Combined oral contraceptive pill* - **Combined oral contraceptive pills (COCs)** contain both estrogen and progestin. Estrogen can negatively impact **milk production** and may not be suitable for breastfeeding mothers, especially in the first 6 months postpartum. - COCs are generally avoided in lactating women until breastfeeding is well-established or after 6 months to prevent interference with **lactation**.
Question 22: A pregnant patient, with a history of classical cesarean section in view of fetal growth retardation in the previous pregnancy, presents to you. She is currently at 35 weeks of gestation with breech presentation. What is the next step in management?
- A. Cesarean section at 37 weeks (Correct Answer)
- B. Advice USG and visit after 2 weeks
- C. Internal podalic version followed by vaginal delivery
- D. External cephalic version at 36 weeks
Explanation: ***Cesarean section at 37 weeks*** - A history of **classical cesarean section** is an absolute contraindication to vaginal birth due to the high risk of **uterine rupture**. - Performing the cesarean section at 37 weeks, rather than waiting longer, minimizes the risk of spontaneous labor and rupture while ensuring fetal maturity. *Advice USG and visit after 2 weeks* - This option does not address the critical risk of **uterine rupture** due to the previous classical cesarean section. - Delaying definitive management by two weeks could increase the risk of spontaneous labor and associated complications. *Internal podalic version followed by vaginal delivery* - An **internal podalic version** is a procedure used to change fetal lie during labor, typically for the second twin, and it is **contraindicated** with a previous classical cesarean due to rupture risk. - Given the previous classical incision, a **vaginal delivery is unsafe** and should not be attempted. *External cephalic version at 36 weeks* - **External cephalic version (ECV)** is generally contraindicated in patients with a history of a **classical cesarean section** due to the increased risk of uterine rupture. - Even if successful, the patient would still require a cesarean section for delivery given the previous uterine scar.
Question 23: A woman with an obstetric score of G2P1 comes to the clinic at 14 weeks of gestation for her antenatal checkup. A uterine artery doppler was suggested by the doctor. What would it detect?
- A. Risk of early-onset preeclampsia (Correct Answer)
- B. Risk of late-onset preeclampsia
- C. Risk of placenta accreta
- D. Fetal growth restriction risk
Explanation: **Risk of early-onset preeclampsia** - **Uterine artery Doppler** at 11-14 weeks of gestation is used to screen for **preeclampsia risk**, particularly **early-onset preeclampsia**, which is associated with impaired placental development. - An increased **pulsatility index (PI)** or presence of **bilateral notching** in the uterine arteries indicates high resistance to blood flow, suggesting a higher risk of developing this condition. *Risk of late-onset preeclampsia* - While uterine artery Doppler can indicate a general risk for preeclampsia, its predictive value is significantly lower for **late-onset preeclampsia** (after 34 weeks). - Late-onset preeclampsia often has different underlying causes, not solely related to abnormal **trophoblast invasion** detectable by early Doppler. *Risk of placenta accreta* - **Placenta accreta** is typically associated with previous **cesarean sections** or other uterine surgeries, leading to abnormal placental implantation. - It is diagnosed by the absence of a clear retroplacental hypoechoic zone and features such as **lacunae** on **ultrasound**, not primarily by uterine artery Doppler. *Fetal growth restriction risk* - Uterine artery Doppler at 11-14 weeks can offer some indication of **fetal growth restriction (FGR)** risk, particularly if severe and related to **placental insufficiency**. - However, the primary surveillance for FGR later in pregnancy often involves **umbilical artery Doppler** and fetal biometry, not solely early uterine artery Doppler.
Pharmacology
1 questionsA female patient presents to you with a unilateral headache. It is associated with nausea, photophobia, and phonophobia. What is the drug of choice for acute management?
NEET-PG 2022 - Pharmacology NEET-PG Practice Questions and MCQs
Question 21: A female patient presents to you with a unilateral headache. It is associated with nausea, photophobia, and phonophobia. What is the drug of choice for acute management?
- A. Flunarizine
- B. Sumatriptan (Correct Answer)
- C. Propranolol
- D. Topiramate
Explanation: ***Sumatriptan*** - **Sumatriptan**, a **triptan**, is an effective abortive therapy for **acute migraine attacks** due to its selective serotonin 5-HT1B/1D receptor agonist action, leading to vasoconstriction and inhibition of neurogenic inflammation. - The symptoms described—**unilateral headache**, nausea, **photophobia**, and **phonophobia**—are classic features of migraine. *Flunarizine* - **Flunarizine** is a **calcium channel blocker** used for migraine **prophylaxis**, not for acute treatment. - It is typically prescribed for patients experiencing frequent or severe migraine attacks to reduce their incidence. *Propranolol* - **Propranolol** is a **beta-blocker** primarily used for migraine **prophylaxis**. - It helps prevent migraine attacks by modulating cerebral blood flow and neuronal excitability, but it is not effective for acute pain relief during an attack. *Topiramate* - **Topiramate** is an **antiepileptic drug** often used for migraine **prophylaxis**. - It works by various mechanisms, including altering neurotransmitter activity, but it does not provide acute symptomatic relief for an ongoing migraine attack.