Biochemistry
1 questionsWhen the insulin:glucagon ratio is decreased, which enzyme is active?
NEET-PG 2020 - Biochemistry NEET-PG Practice Questions and MCQs
Question 331: When the insulin:glucagon ratio is decreased, which enzyme is active?
- A. Glucokinase
- B. Phosphofructokinase
- C. Hexokinase
- D. Glucose-6-phosphatase (Correct Answer)
Explanation: ***Glucose-6-phosphatase*** - A decreased insulin:glucagon ratio indicates a **fasting state** or **catabolic state**, promoting glucose production and release rather than storage. - **Glucose-6-phosphatase** is the key enzyme that enables glucose release from the liver by removing the phosphate group from glucose-6-phosphate, producing free glucose that can exit hepatocytes. - This enzyme is active during both **gluconeogenesis** and **glycogenolysis** and is only present in liver, kidney, and intestinal cells. *Glucokinase* - **Glucokinase** is active in the **fed state** when insulin levels are high and the insulin:glucagon ratio is increased. - It phosphorylates glucose to trap it in hepatocytes for glycogen synthesis and metabolism, which is the opposite of what occurs during fasting. *Phosphofructokinase* - **Phosphofructokinase (PFK-1)** is the rate-limiting enzyme of **glycolysis**, active when glucose needs to be broken down for energy. - It is stimulated by high insulin:glucagon ratios and inhibited during fasting when gluconeogenesis (the reverse pathway) is active. *Hexokinase* - **Hexokinase** phosphorylates glucose in peripheral tissues for intracellular utilization. - During a low insulin:glucagon ratio, the priority is glucose **release** from the liver, not glucose **uptake** and phosphorylation in tissues.
ENT
1 questionsPartial and full closure of nasal passages is characteristically seen in:
NEET-PG 2020 - ENT NEET-PG Practice Questions and MCQs
Question 331: Partial and full closure of nasal passages is characteristically seen in:
- A. Allergic rhinitis
- B. Atrophic rhinitis
- C. Occupational rhinitis
- D. Vasomotor rhinitis (Correct Answer)
Explanation: ***Vasomotor rhinitis*** - This condition is characterized by **vascular dysregulation** in the nasal mucosa, leading to episodic **swelling** and **congestion** that can result in partial or full nasal closure without an identifiable allergic or infectious cause. - Symptoms are often triggered by **non-specific irritants** like temperature changes, strong odors, or emotional stress, causing the nasal blood vessels to dilate excessively. *Allergic rhinitis* - While it causes nasal congestion and obstruction, the primary mechanism is an **IgE-mediated inflammatory response** to specific allergens, leading to mucosal edema and increased mucus production. - The closure is typically accompanied by other allergic symptoms such as **sneezing**, **itching**, and **rhinorrhea**, which differentiates it from vasomotor rhinitis. *Atrophic rhinitis* - This condition involves **progressive atrophy** of the nasal mucosa, turbinates, and underlying bone, resulting in an abnormally wide nasal passage rather than obstruction. - Patients typically experience **paradoxical nasal obstruction** due to altered airflow dynamics and crusting, alongside a characteristic foul odor. *Occupational rhinitis* - This type of rhinitis is caused by **exposure to specific agents** in the workplace, leading to inflammation and nasal obstruction, often accompanied by sneezing and rhinorrhea. - Symptom onset is directly linked to **workplace exposure** and improves away from the occupational environment, which is not suggested by the general term "partial and full closure."
Radiology
1 questionsCancer patient undergoes radiotherapy, pick the true statement for radiosensitivity of tissues?
NEET-PG 2020 - Radiology NEET-PG Practice Questions and MCQs
Question 331: Cancer patient undergoes radiotherapy, pick the true statement for radiosensitivity of tissues?
- A. GI mucosa is one of the most radioresistant tissues in the body
- B. Rapidly dividing cells are resistant to radiation
- C. Small blood vessels are radiosensitive tissues (Correct Answer)
- D. The intensity of radiation is inversely proportional to the square of distance from the source
Explanation: ***Small blood vessels are radiosensitive tissues*** - **Endothelial cells** lining small blood vessels are actively dividing and have a relatively short lifespan, making them susceptible to radiation-induced damage. - Damage to these vessels can lead to **fibrosis** and **tissue hypoxia**, contributing to late radiation effects. *GI mucosa is one of the most radioresistant tissues in the body* - The **GI mucosa** is one of the **most radiosensitive** tissues due to its rapid cell turnover and high proliferative capacity, leading to symptoms like mucositis and diarrhea after radiation. - The constant renewal of epithelial cells makes them highly vulnerable to the **cytotoxic effects** of radiation. *Rapidly dividing cells are resistant to radiation* - **Rapidly dividing cells**, such as those in the bone marrow, GI crypts, and hair follicles, are generally **most sensitive** to radiation. - This forms the basis of radiation therapy, as cancer cells often have a higher proliferative rate than many normal tissues, making them a target. *The intensity of radiation is inversely proportional to the square of distance from the source* - This statement describes the **inverse square law** for radiation intensity, which is true, but it is a principle of radiation physics, not a statement about the radiosensitivity of tissues. - The inverse square law dictates how radiation dose **attenuates with distance**, which is critical for dose calculation but not directly about biological radiosensitivity.
Surgery
1 questionsIn the primary survey, which of the following is not included?
NEET-PG 2020 - Surgery NEET-PG Practice Questions and MCQs
Question 331: In the primary survey, which of the following is not included?
- A. ABC
- B. CECT to look for bleeding (Correct Answer)
- C. Exposure of the whole body
- D. Recording BP
Explanation: ***CECT to look for bleeding*** - A **CECT scan** is a detailed imaging study that is performed during the **secondary survey**, not during the primary survey. - The primary survey focuses on the immediate **ABCDE assessment** (Airway, Breathing, Circulation, Disability, Exposure) to identify and treat immediately life-threatening conditions. - While identifying bleeding is critical, detailed imaging like CECT is done only after initial stabilization is achieved in the primary survey. *ABC* - **Airway, Breathing, and Circulation (ABC)** are the fundamental first three components of the primary survey. - These represent the immediate priorities for life support in trauma management according to ATLS guidelines. - Ensuring a patent airway, adequate breathing, and circulatory stability are critical first steps. *Exposure of the whole body* - **Exposure** (the "E" in ABCDE) is an essential part of the primary survey. - Complete exposure allows full assessment for injuries and prevents missing critical external wounds. - This step also involves maintaining **thermoregulation** to prevent hypothermia. *Recording BP* - **Recording blood pressure** is a crucial part of assessing circulation (the "C") during the primary survey. - It helps quickly evaluate hemodynamic status and identify potential signs of shock or internal bleeding. - Vital signs monitoring is integral to the initial trauma assessment.