NEET-PG 2015 Practice Questions

Q: Bile acids are synthesized from ?

Cholesterol. ***Cholesterol*** - **Bile acids** are derivatives of **cholesterol**, synthesized in the liver through a multi-step enzymatic pathway. - The conversion of cholesterol to bile acids is a primary mechanism for the excretion and transport of cholesterol from the body. *Heme* - **Heme** is a component of hemoglobin and myoglobin, primarily involved in oxygen transport and storage. - Its degradation product is **bilirubin**, which forms part of bile but is distinct from bile acids. *Ribulose* - **Ribulose** is a 5-carbon sugar, playing a key role in the **pentose phosphate pathway** and the **Calvin cycle** in photosynthesis. - It is not a precursor for bile acid synthesis. *Arachidonic acid* - **Arachidonic acid** is a polyunsaturated fatty acid that serves as a precursor for **eicosanoids** (prostaglandins, thromboxanes, and leukotrienes). - These molecules are involved in inflammation and immune responses but are unrelated to bile acid synthesis.

Q: Which of the following statements are true regarding the visual cycle cascade?

All of the options are true. ***All of the statements are true*** The visual cycle cascade involves multiple interconnected events in phototransduction: **Light causes isomerization of 11-cis-retinal to all-trans-retinal** - This is the **primary photochemical event** that initiates vision - Light absorption causes the **cis-trans isomerization** in less than a picosecond - This conformational change is the only light-dependent step in the entire cascade **Retinal is involved in the visual cycle** - **11-cis-retinal** serves as the chromophore bound to opsin forming rhodopsin - After isomerization to **all-trans-retinal**, it must be converted back to 11-cis-retinal - This regeneration occurs through the **retinoid cycle** involving RPE cells **Involves a conformational change in opsin** - The isomerization of retinal triggers **conformational changes in opsin** - This converts rhodopsin to **metarhodopsin II** (the active form) - Activated opsin then activates **transducin** (G-protein), amplifying the signal and leading to hyperpolarization of photoreceptor cells All three statements accurately describe essential components of the visual cycle cascade.

Q: Best temperature for putrefaction is -

10-45 °C. ***10-45 °C*** - This temperature range is optimal for the **bacterial and enzymatic activity** required for putrefaction, as most decomposition bacteria thrive in mesophilic conditions. - Temperatures within this range accelerate the breakdown of complex organic matter into simpler compounds, leading to the characteristic changes of **decomposition**. *0-10 °C* - Temperatures below 10°C significantly **slow down bacterial metabolism** and enzymatic activity, thereby retarding the process of putrefaction. - At temperatures near 0°C, decomposition is almost entirely halted due to **cold preservation** effects. *45-100 °C* - Temperatures above 45°C can begin to **denature enzymes** and kill many of the bacteria responsible for putrefaction, especially as temperatures approach the upper end of this range. - While some thermophilic bacteria exist, the overall rate of decomposition for a cadaver typically **decreases at very high temperatures** due to sterilization effects or protein coagulation. *100-150 °C* - At these very high temperatures, most **bacteria would be destroyed**, and enzymatic activity would be completely inhibited due to extensive protein denaturation. - Such temperatures are more likely to cause **cremation or desiccation** rather than putrefaction.

Q: What is the most common nephropathy associated with malignancy?

Membranous glomerulonephritis. ***Membranous glomerulonephritis*** - **Membranous glomerulonephritis** has the strongest and most frequent association with solid organ malignancies, particularly in older patients. - While other glomerulopathies can be linked to cancer, **membranous nephropathy** is the most common paraneoplastic glomerulopathy in adults. *Focal segmental glomerulosclerosis (FSGS)* - While FSGS can be associated with certain cancers, particularly hematological malignancies and HIV-associated nephropathy, it is **less common** than membranous nephropathy in solid tumors. - The link is often with **HIV-associated nephropathy** or direct tumor effects rather than a paraneoplastic syndrome. *Minimal change disease* - Minimal change disease is predominantly seen in **children** and is less frequently associated with malignancy compared to membranous nephropathy. - When associated with malignancy, it is typically with **lymphoproliferative disorders** like Hodgkin lymphoma. *IgA nephropathy* - **IgA nephropathy** is the most common primary glomerulonephritis worldwide but has a **weak and inconsistent association** with malignancy. - Its presence alongside cancer is often coincidental rather than directly causative.

Q: Radiotherapy induced radiation pneumonitis is mediated by all of the following cytokines and factors except -

PAF. ***PAF*** - **Platelet-activating factor (PAF)** is primarily involved in **anaphylaxis**, **asthma**, and **allergic responses**, mediating inflammation through platelet aggregation and smooth muscle contraction. - While it has pro-inflammatory effects, it is **not a primary mediator** of the specific inflammatory cascade seen in radiotherapy-induced radiation pneumonitis. *TNF-α* - **Tumor Necrosis Factor-alpha (TNF-α)** is a crucial **pro-inflammatory cytokine** that plays a significant role in the initial acute phase of radiation pneumonitis. - It induces **cytotoxicity**, **apoptosis**, and the production of other inflammatory mediators, contributing to lung tissue damage. *TGF-β* - **Transforming Growth Factor-beta (TGF-β)** is a key cytokine involved in the **fibrotic phase** of radiation pneumonitis. - It promotes **fibroblast proliferation**, collagen synthesis, and extracellular matrix deposition, leading to lung scarring. *NF-kB* - **Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kB)** is a master **transcription factor** that regulates the expression of numerous genes involved in inflammation and immune responses. - Radiation exposure **activates NF-kB**, leading to the transcription of various pro-inflammatory cytokines, including TNF-α, which contribute to radiation pneumonitis.

Q: Which of the following is the most characteristic sexual side effect of SSRIs?

Delayed ejaculation. ***Delayed ejaculation*** - **Delayed ejaculation** is a common and characteristic sexual side effect of SSRIs due to their impact on serotonin pathways involved in sexual response. - This effect can lead to significant distress and non-adherence to treatment, and often requires dose adjustment or switching to an alternative antidepressant. *Erectile dysfunction* - While **erectile dysfunction** can occur with SSRIs, it is a less specific and less consistently reported sexual side effect compared to ejaculatory dysfunction. - Many factors, including underlying mood disorder and comorbidities, can contribute to erectile dysfunction, making it less characteristic of SSRI use alone. *Retrograde ejaculation* - **Retrograde ejaculation** is a condition where semen enters the bladder during orgasm, and while it can be a side effect of some medications (e.g., alpha-blockers), it is not a hallmark sexual side effect of SSRIs. - SSRIs primarily affect the process of emission and expulsion, leading more commonly to delayed or absent ejaculation rather than retrograde flow. *Anxiety* - **Anxiety** is generally a *primary symptom* of the conditions SSRIs are prescribed to treat, such as depression or anxiety disorders, not a sexual side effect of the medication itself. - Although SSRIs can initially cause or worsen anxiety in some patients before therapeutic effects are seen, this is a systemic side effect, not a sexual one.

Q: Which of the following is the longest acting carbapenem?

Ertapenem. ***Ertapenem*** - **Ertapenem** has the **longest half-life** among the carbapenems, allowing for once-daily dosing. - Its prolonged action is due to its **chemical structure**, which provides high protein binding and reduced renal clearance compared to other carbapenems. *Imipenem* - **Imipenem** has a **relatively short half-life** and requires co-administration with cilastatin to prevent its renal metabolism by dehydropeptidase-1. - Its short duration of action necessitates **frequent dosing**, typically every 6 to 8 hours. *Meropenem* - **Meropenem** has a **shorter half-life** than ertapenem, generally requiring dosing every 8 hours. - Although it does not require cilastatin, its pharmacokinetic profile is not as extended as ertapenem's. *Doripenem* - **Doripenem** also has a **shorter half-life** than ertapenem, necessitating administration every 8 hours. - Its spectrum of activity is similar to meropenem, but it does not offer the same extended duration of action.

Q: Broca's area is primarily involved in which of the following functions?

Speech production. ***Speech production*** - **Broca's area** is a region in the frontal lobe of the dominant hemisphere, typically the left, that is crucial for the formation of coherent and grammatically correct speech. - Damage to this area leads to **Broca's aphasia**, characterized by **non-fluent speech**, difficulty retrieving words, and impaired syntax. *Language comprehension* - **Wernicke's area**, located in the temporal lobe, is primarily responsible for **language comprehension**. - Patients with **Wernicke's aphasia** can produce fluent speech but have difficulty understanding spoken and written language. *Language repetition* - The **arcuate fasciculus**, a bundle of nerve fibers connecting Broca's and Wernicke's areas, is essential for **language repetition**. - Lesions in this pathway result in **conduction aphasia**, where comprehension and fluency are relatively preserved, but repetition is severely impaired. *Reading ability* - Reading ability involves a complex network of brain regions, including the **angular gyrus** and **visual cortex**, in addition to language areas. - While Broca's area contributes to the motor planning aspects of reading aloud, it is not its primary function.

Q: Which of the following drugs is not used in the treatment of akathisia?

Haloperidol. ***Haloperidol*** - **Haloperidol** is a typical antipsychotic drug known to **cause** or worsen **akathisia**, rather than treat it. - Akathisia is an extrapyramidal symptom, and **first-generation antipsychotics** like haloperidol are frequent culprits due to their strong **D2 receptor blockade**. *Benzodiazepine* - **Benzodiazepines** like lorazepam or clonazepam are often used to treat akathisia due to their **sedative** and **anxiolytic** properties. - They act by enhancing **GABAergic transmission**, which can help calm the motor restlessness associated with akathisia. *Propranolol* - **Propranolol**, a **beta-blocker**, is a first-line treatment for akathisia, particularly effective for its objective motor symptoms. - It works by reducing **adrenergic activity**, which is thought to contribute to the motor restlessness. *Trihexyphenidyl* - **Trihexyphenidyl** is an **anticholinergic** agent primarily used to treat **parkinsonian-like extrapyramidal symptoms** (e.g., dystonia, pseudoparkinsonism). - While sometimes used for generalized EPS, it is **less effective** for the specific motor restlessness of akathisia compared to beta-blockers or benzodiazepines.

Q: Solution currently used for liver preservation for transplantation is?

University of Wisconsin (UW) solution. ***University of Wisconsin (UW) solution*** - The **University of Wisconsin (UW) solution** is widely considered the gold standard for **organ preservation**, particularly for liver transplantation, due to its superior ability to extend cold ischemia time. - It contains a unique blend of components, including **lactobionate, raffinose, and hydroxyethyl starch**, which help to minimize cellular swelling, prevent free radical injury, and maintain cellular integrity during cold storage. *IGL-1 solution* - **IGL-1** is a more recent preservation solution designed to be used with **machine perfusion** systems. - While showing promise, it is **not yet as universally adopted** as UW solution for static cold storage of livers. *Ross Marshall Citrate solution* - The **Ross Marshall Citrate solution** was an older solution primarily used for **kidney preservation**. - It has been largely **superseded by newer solutions** with improved efficacy for liver and other organ preservation. *Kyoto ET solution* - **Kyoto ET solution** is another preservation solution primarily used in **Japan**, particularly for **kidney and pancreas preservation**. - While effective for those organs, it is **not the most commonly used** or preferred solution for liver preservation globally.

Question 1

Bile acids are synthesized from ?

Accepted Answer

Cholesterol

Answer

Heme

Answer

Ribulose

Answer

Arachidonic acid

Question 2

Which of the following statements are true regarding the visual cycle cascade?

Accepted Answer

All of the options are true

Answer

Light causes isomerization of 11-cis-retinal to all-trans-retinal

Answer

Retinal is involved in the visual cycle

Answer

Involves a conformational change in opsin

Question 3

Best temperature for putrefaction is -

Accepted Answer

10-45 °C

Answer

0-10 °C

Answer

45-100 °C

Answer

100-150 °C

Question 4

What is the most common nephropathy associated with malignancy?

Accepted Answer

Membranous glomerulonephritis

Answer

Focal segmental glomerulosclerosis (FSGS)

Answer

Minimal change disease

Answer

IgA nephropathy

Question 5

Radiotherapy induced radiation pneumonitis is mediated by all of the following cytokines and factors except -

Accepted Answer

PAF

Answer

NF-kB

Answer

TNF-α

Answer

TGF-β

Question 6

Which of the following is the most characteristic sexual side effect of SSRIs?

Accepted Answer

Delayed ejaculation

Answer

Retrograde ejaculation

Answer

Erectile dysfunction

Answer

Anxiety

Question 7

Which of the following is the longest acting carbapenem?

Accepted Answer

Ertapenem

Answer

Imipenem

Answer

Meropenem

Answer

Doripenem

Question 8

Broca's area is primarily involved in which of the following functions?

Accepted Answer

Speech production

Answer

Language comprehension

Answer

Language repetition

Answer

Reading ability

Question 9

Which of the following drugs is not used in the treatment of akathisia?

Accepted Answer

Haloperidol

Answer

Benzodiazepine

Answer

Propranolol

Answer

Trihexyphenidyl

Question 10

Solution currently used for liver preservation for transplantation is?

Accepted Answer

University of Wisconsin (UW) solution

Answer

IGL-1 solution

Answer

Ross Marshall Citrate solution

Answer

Kyoto ET solution

NEET-PG 2015

Biochemistry

Forensic Medicine

Pathology

Pharmacology

Physiology

Psychiatry

Surgery