Biochemistry
2 questionsWhat do chaperones assist in?
Which vitamin deficiency is associated with night blindness?
NEET-PG 2018 - Biochemistry NEET-PG Practice Questions and MCQs
Question 111: What do chaperones assist in?
- A. Protein Cleavage
- B. Protein Degradation
- C. Protein Modification
- D. Protein Folding (Correct Answer)
Explanation: ***Protein Folding*** - **Chaperone proteins** bind to newly synthesized polypeptide chains and unfolded proteins, helping them achieve their **correct three-dimensional structure**. - They also prevent **misfolding** and **aggregation** of proteins, which can be detrimental to cellular function. *Protein Cleavage* - **Protein cleavage** involves the enzymatic hydrolysis of peptide bonds, often performed by **proteases**. - This process is not directly facilitated by chaperones; chaperones primarily function in structural maturation, not degradation or processing. *Protein Degradation* - **Protein degradation** is carried out by systems like the **ubiquitin-proteasome pathway** or lysosomes, which break down damaged or unwanted proteins. - While chaperones can triage misfolded proteins for degradation, they do not directly perform the degradation themselves. *Protein Modification* - **Protein modification** involves the covalent attachment of chemical groups (e.g., phosphorylation, glycosylation) or other molecules to a protein. - This process is performed by specific enzymes like kinases or glycosyltransferases; chaperones’ role is more structural than enzymatic modification.
Question 112: Which vitamin deficiency is associated with night blindness?
- A. Biotin
- B. Vit. A (Correct Answer)
- C. Thiamine
- D. Riboflavin
Explanation: ***Vitamin A*** - **Vitamin A deficiency is THE classic cause of night blindness (nyctalopia)**, one of the earliest signs of deficiency - Vitamin A is essential for synthesis of **rhodopsin**, the photopigment in retinal rod cells responsible for vision in dim light - Deficiency leads to impaired dark adaptation and progressive loss of night vision - Other manifestations include **xerophthalmia, Bitot's spots, and keratomalacia** - This is a high-yield fact for NEET-PG examinations *Riboflavin (Vitamin B2)* - Riboflavin deficiency causes **oral-ocular-genital syndrome** - Clinical features include **angular stomatitis, cheilosis, glossitis, seborrheic dermatitis** - Eye manifestations include **corneal vascularization and photophobia**, NOT night blindness - Does NOT cause night blindness as a primary symptom *Thiamine (Vitamin B1)* - Thiamine deficiency causes **Beriberi** (wet and dry forms) and **Wernicke-Korsakoff syndrome** - Characterized by peripheral neuropathy, cardiac dysfunction, and CNS manifestations - Does NOT cause night blindness *Biotin (Vitamin B7)* - Biotin deficiency is rare and causes **dermatitis, alopecia, conjunctivitis** - Also causes neurological symptoms in severe deficiency - Does NOT cause night blindness
Dermatology
1 questionsWhich of the following statements about keloids is MOST true?
NEET-PG 2018 - Dermatology NEET-PG Practice Questions and MCQs
Question 111: Which of the following statements about keloids is MOST true?
- A. Keloids may extend beyond the original wound. (Correct Answer)
- B. Extended excision is often not the treatment of choice.
- C. It contains growth factors.
- D. None of the options.
Explanation: ***Keloids may extend beyond the original wound.*** - Keloids are characterized by their **overgrowth** beyond the boundaries of the original injury. - This distinguishes them from **hypertrophic scars**, which remain confined to the wound edges. *Extended excision is often not the treatment of choice.* - **Excision alone** is usually insufficient for keloids and can even be counterproductive, as the recurring wound often leads to a larger keloid. - While excision can be part of a treatment plan, it is typically combined with supplementary therapies like **steroid injections** or **radiation therapy** to prevent recurrence. *It contains growth factors.* - While keloids involve abnormal fibroblast activity and deposition of **extracellular matrix**, the statement that it "contains growth factors" is too vague and not a defining characteristic that differentiates it from a range of other tissues or conditions. - Many tissues and healing processes involve growth factors, so this statement alone does not provide a specific or most true characteristic of keloids. *None of the options.* - This option is incorrect because the statement that **keloids may extend beyond the original wound** is a hallmark characteristic of keloids and is definitively true.
Microbiology
2 questionsAcute Hemorrhagic Conjunctivitis is primarily caused by which type of Enterovirus?
Cutaneous larva migrans is caused by which organism?
NEET-PG 2018 - Microbiology NEET-PG Practice Questions and MCQs
Question 111: Acute Hemorrhagic Conjunctivitis is primarily caused by which type of Enterovirus?
- A. Enterovirus type 68
- B. Enterovirus type 69
- C. Enterovirus type 70 (Correct Answer)
- D. Enterovirus type 71
Explanation: ***Enterovirus type 70*** - **Enterovirus type 70** is the most common cause of **Acute Hemorrhagic Conjunctivitis (AHC)**, particularly in epidemic outbreaks. - AHC presents with rapid onset of **ocular pain**, **redness**, **swelling**, and **subconjunctival hemorrhages**. *Enterovirus type 68* - **Enterovirus D68 (EV-D68)** is primarily known for causing **respiratory illnesses**, ranging from mild to severe, and is associated with acute flaccid myelitis. - While it can cause respiratory symptoms, it is not a primary cause of **Acute Hemorrhagic Conjunctivitis**. *Enterovirus type 69* - **Enterovirus type 69** is a rare serotype and is not typically associated with specific human diseases or large-scale outbreaks. - Unlike EV70, it is not recognized as a significant cause of **conjunctivitis**. *Enterovirus type 71* - **Enterovirus A71 (EV-A71)** is a common cause of **hand, foot, and mouth disease (HFMD)**, especially in children, and can also lead to severe neurological complications. - While it causes various infections, it is not the primary cause of **hemorrhagic conjunctivitis**.
Question 112: Cutaneous larva migrans is caused by which organism?
- A. Strongyloides
- B. Toxocara canis
- C. Ancylostoma braziliense (Correct Answer)
- D. Necator americanus
Explanation: ***Ancylostoma braziliense*** - This **hookworm** species commonly found in dogs and cats is the most frequent cause of **cutaneous larva migrans** in humans. - The larvae penetrate the skin but cannot complete their life cycle in humans, instead migrating aimlessly creating **serpiginous tracks**. *Strongyloides* - **_Strongyloides stercoralis_** causes **strongyloidiasis**, which presents with a rapidly advancing (up to 10 cm/hr) migratory rash known as **larva currens**, and not the slower cutaneous larva migrans. - It differs from cutaneous larva migrans in its ability to complete its life cycle in humans, leading to **autoinfection**. *Toxocara canis* - **_Toxocara canis_** is the causative agent of **visceral larva migrans** and **ocular larva migrans**, not cutaneous larva migrans. - In visceral larva migrans, larvae migrate through internal organs, causing symptoms like **hepatomegaly** and **eosinophilia**. *Necator americanus* - This is a human hookworm that can cause **iron deficiency anemia** due to chronic blood loss in the intestines. - While its larvae can penetrate the skin, causing a transient itchy rash known as **ground itch**, they do not cause the prolonged, migratory cutaneous larva migrans.
Obstetrics and Gynecology
2 questionsWhat are the effects of Progesterone-only pills?
Extramammary Paget's disease of the vulva is most commonly associated with which other cancer?
NEET-PG 2018 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 111: What are the effects of Progesterone-only pills?
- A. All of the options may occur (Correct Answer)
- B. May suppress ovulation
- C. Thins the lining of the uterus
- D. Thickens cervical mucus
Explanation: ***All of the options may occur*** - Progesterone-only pills (POPs) work through **multiple complementary mechanisms** that collectively provide effective contraception. - All three effects occur simultaneously and contribute to the overall contraceptive efficacy of POPs. - Understanding these mechanisms helps explain why POPs are effective despite lower hormone doses compared to combined oral contraceptives. **Mechanism 1: May suppress ovulation** - POPs can **partially suppress ovulation**, preventing the release of an egg. - Traditional POPs suppress ovulation in approximately 40-60% of cycles, while newer desogestrel-containing POPs achieve higher rates (97-99%). - This effect depends on the dose and type of progestin used in the formulation. **Mechanism 2: Thins the lining of the uterus** - Progesterone causes **endometrial atrophy**, making the uterine lining thin and unsuitable for embryo implantation. - This hostile uterine environment acts as a backup contraceptive mechanism if ovulation and fertilization occur. - Endometrial changes occur consistently with POP use. **Mechanism 3: Thickens cervical mucus** - This is the **primary and most consistent mechanism** of POPs. - Progesterone significantly **increases cervical mucus viscosity** and reduces its quantity within hours of administration. - The thickened mucus creates a physical barrier that prevents sperm penetration, motility, and viability.
Question 112: Extramammary Paget's disease of the vulva is most commonly associated with which other cancer?
- A. Vulvar cancer (Correct Answer)
- B. Vaginal cancer
- C. Cervical cancer
- D. Uterine cancer
Explanation: ***Vulvar cancer*** - **Extramammary Paget's disease (EMPD)** frequently presents in the vulvar region and is associated with an underlying **adenocarcinoma** in up to 30% of cases. - The disease involves intraepithelial adenocarcinoma cells that can spread locally and, in some instances, indicates a synchronous or metachronous **internal malignancy**, often of genitourinary or gastrointestinal origin, but primarily vulvar adenocarcinoma in this context. *Vaginal cancer* - While Paget's disease can occur in other anogenital areas, its association with **primary vaginal cancer** is much less common compared to vulvar involvement. - **Vaginal Paget's disease** is rare and usually represents secondary spread from a vulvar primary or an underlying bladder/urethral carcinoma. *Cervical cancer* - **Paget's disease** is not typically associated with **cervical cancer**. Cervical cancers are predominantly squamous cell carcinomas or adenocarcinomas arising from the transformation zone. - While cervical adenocarcinoma can present with similar cells to Paget's, it is a distinct entity and not a common association. *Uterine cancer* - **Uterine cancer**, primarily endometrial carcinoma, has no direct or common association with **Paget's disease**. - Paget's disease primarily affects the skin and can be associated with underlying gland cancers, but these are generally in proximity to the epidermal involvement rather than distant uterine sites.
Pharmacology
2 questionsWhat is the physiological dose of hydrocortisone (mg/m2/day)?
Which drug decreases the bone resorption in osteoporosis?
NEET-PG 2018 - Pharmacology NEET-PG Practice Questions and MCQs
Question 111: What is the physiological dose of hydrocortisone (mg/m2/day)?
- A. 20-25 mg/m²/day
- B. 15-18 mg/m²/day
- C. 10-12 mg/m²/day (Correct Answer)
- D. 8-10 mg/m²/day
Explanation: ***10-12 mg/m²/day*** - This range represents the typical **physiological replacement dose** of hydrocortisone, mimicking the body's natural cortisol production. - This dose is used for patients with **adrenal insufficiency** to maintain normal metabolic functions without causing significant side effects. *8-10 mg/m²/day* - This dose is slightly on the lower side of the accepted physiological range and might not be sufficient for complete replacement in all individuals. - While close, it is not the most commonly cited optimal physiological dose for hydrocortisone replacement. *15-18 mg/m²/day* - This dose is typically considered above the physiological replacement level and may begin to cause **mild corticosteroid side effects** with prolonged use. - It might be used for short periods or in specific conditions, but not as a standard physiological replacement. *20-25 mg/m²/day* - This dose is well above the physiological range and would be considered a **pharmacological dose** often used for its anti-inflammatory or immunosuppressive effects. - Prolonged use at this dose would likely lead to significant **corticosteroid side effects** such as Cushingoid features, osteoporosis, and hyperglycemia.
Question 112: Which drug decreases the bone resorption in osteoporosis?
- A. Teriparatide
- B. Risedronate (Correct Answer)
- C. Cortisone
- D. Cimetidine
Explanation: ***Risedronate*** - **Risedronate** is a **bisphosphonate**, a class of drugs that inhibits osteoclast activity, thereby decreasing **bone resorption**. - By reducing the rate at which bone is broken down, it helps to preserve **bone mineral density** in patients with osteoporosis. *Teriparatide* - **Teriparatide** is a **parathyroid hormone analog** that primarily works by stimulating **osteoblast activity** to promote new bone formation. - While it treats osteoporosis, its primary mechanism is **anabolic** (bone building), not directly decreasing bone resorption as its main effect. *Cortisone* - **Cortisone** is a **glucocorticoid** that can actually *worsen* osteoporosis by increasing **bone resorption** and decreasing **bone formation** with long-term use. - It is used to treat inflammatory conditions, not to decrease bone resorption for osteoporosis. *Cimetidine* - **Cimetidine** is an **H2-receptor antagonist** used to reduce stomach acid production, commonly for conditions like GERD or ulcers. - It has no known effect on **bone metabolism** or **osteoporosis**.
Surgery
1 questionsWhich of the following statements is true about the suture material shown in the image?
NEET-PG 2018 - Surgery NEET-PG Practice Questions and MCQs
Question 111: Which of the following statements is true about the suture material shown in the image?
- A. Made of cat submucosa
- B. Not degraded
- C. Made of rabbit submucosa
- D. Degraded by enzymatic degradation (Correct Answer)
Explanation: ***Degraded by enzymatic degradation*** - Catgut sutures are **natural absorbable sutures** made primarily from purified collagen. - Their absorption in the body occurs through **enzymatic degradation** and phagocytosis, which is a key characteristic distinguishing them from synthetic absorbable sutures that undergo hydrolysis. *Made of cat submucosa* - While historically referred to as "catgut," these sutures are not actually made from cat intestines. - They are typically derived from the **submucosa of sheep or goat intestines**. *Not degraded* - Catgut sutures are explicitly classified as **absorbable surgical sutures**, as stated on the packaging. - Absorbable sutures by definition are designed to be broken down and **resorbed by the body** over time. *Made of rabbit submucosa* - Catgut sutures are not typically made from rabbit submucosa. - The primary sources for natural absorbable sutures like catgut are the **intestines of sheep or goats**.