Anatomy
3 questionsWhich of the following statements is false about the right bronchus?
Interosseous membrane of forearm is pierced by?
Which muscle is attached to the lateral surface of the greater trochanter?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 91: Which of the following statements is false about the right bronchus?
- A. Shorter
- B. More horizontal (Correct Answer)
- C. In the line of trachea
- D. Wider
Explanation: ***More horizontal*** - The right bronchus is traditionally described as **more vertical** or **more directly in line with the trachea** compared to the left bronchus. - This anatomical orientation makes it more susceptible to the aspiration of foreign bodies. *Shorter* - The **right main bronchus** is indeed shorter than the left main bronchus. - Its length is typically 2-3 cm, while the left main bronchus is about 5 cm long. *Wider* - The **right main bronchus** has a larger diameter than the left main bronchus. - This wider lumen contributes to the ease with which foreign bodies can enter it. *In the line of trachea* - The right main bronchus diverges from the trachea at a **less acute angle** (approximately 25 degrees) compared to the left (approximately 45 degrees). - This makes it appear more as a **direct continuation of the trachea**, facilitating aspiration into the right lung.
Question 92: Interosseous membrane of forearm is pierced by?
- A. Brachial artery
- B. Anterior interosseous artery (Correct Answer)
- C. Posterior interosseous artery
- D. Ulnar recurrent artery
Explanation: ***Anterior interosseous artery*** - The **anterior interosseous artery** pierces the **interosseous membrane** in the **distal forearm** (approximately 5 cm above the wrist) to anastomose with the **posterior interosseous artery** and contribute to the **palmar carpal arch**. - This artery arises from the **common interosseous artery**, a branch of the **ulnar artery**. - This is the **classically taught structure** that pierces the interosseous membrane and is the standard answer in examination contexts. *Brachial artery* - The **brachial artery** is the main artery of the arm and terminates in the **cubital fossa** by dividing into the **radial** and **ulnar arteries**. - It does not pierce the **interosseous membrane** of the forearm as it is located in the arm, not the forearm. *Posterior interosseous artery* - The **posterior interosseous artery** arises from the **common interosseous artery** and passes **posteriorly between the oblique cord and the upper border of the interosseous membrane** to enter the posterior compartment of the forearm. - While it may pierce the membrane distally to anastomose anteriorly, the **anterior interosseous artery** is the structure **classically described** as piercing the membrane in standard anatomical teaching and examination contexts. *Ulnar recurrent artery* - The **ulnar recurrent arteries** (anterior and posterior branches) arise from the **ulnar artery** near the **cubital fossa** and ascend to participate in the **anastomosis around the elbow joint**. - These arteries do not pierce the **interosseous membrane** of the forearm.
Question 93: Which muscle is attached to the lateral surface of the greater trochanter?
- A. Gluteus maximus
- B. Gluteus medius (Correct Answer)
- C. Gluteus minimus
- D. Piriformis
Explanation: ***Gluteus medius*** - The **gluteus medius** inserts onto the **lateral surface of the greater trochanter** of the femur. - Its primary actions include **abduction** and **internal rotation** of the hip. *Gluteus maximus* - The **gluteus maximus** inserts primarily into the **iliotibial tract** and the **gluteal tuberosity** of the posterior femur, not the lateral greater trochanter. - Its main roles are **hip extension** and **external rotation**. *Gluteus minimus* - The **gluteus minimus** inserts onto the **anterior part of the lateral surface (anterolateral aspect)** of the greater trochanter, anterior to the gluteus medius insertion. - Like the gluteus medius, it also contributes to **hip abduction** and **internal rotation**. *Piriformis* - The **piriformis** muscle inserts onto the **superior and medial aspect of the greater trochanter**. - Its main actions are **external rotation** and **abduction** of the hip, particularly when the hip is flexed.
Biochemistry
3 questionsWhat is the major site of protein glycosylation?
Which element is required by phosphofructokinase?
What is the normal range of ferritin levels in adult males?
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 91: What is the major site of protein glycosylation?
- A. Ribosome and Golgi body
- B. ER and Ribosome
- C. Ribosome and Cytoplasm
- D. ER and Golgi body (Correct Answer)
Explanation: ***ER and Golgi body*** - The **endoplasmic reticulum (ER)** is the primary site for **N-linked glycosylation**, where carbohydrates are added to the asparagine residues of nascent proteins. - The **Golgi apparatus** is crucial for further modification and processing of these N-linked glycans, as well as the site for **O-linked glycosylation**, where sugars are added to serine or threonine residues. *Ribosome and Golgi body* - **Ribosomes** are responsible for **protein synthesis (translation)** but do not directly perform glycosylation, which is a post-translational modification. - While the **Golgi body** is a site of glycosylation, the ribosome's inclusion makes this option incorrect as the ribosome's role precedes glycosylation. *ER and Ribosome* - The **ER** is a major site of protein glycosylation, especially N-linked glycosylation. - However, **ribosomes** are involved in protein synthesis and lack the enzymatic machinery for adding sugar moieties to proteins. *Ribosome and Cytoplasm* - **Ribosomes** synthesize proteins, but glycosylation does not occur there. - The **cytoplasm** is the site for many metabolic pathways, but major protein glycosylation events mostly occur within the ER and Golgi.
Question 92: Which element is required by phosphofructokinase?
- A. Magnesium (Correct Answer)
- B. Inorganic phosphate
- C. Manganese
- D. Copper
Explanation: **Magnesium** - **Phosphofructokinase** (PFK) is an enzyme in **glycolysis** that catalyzes the phosphorylation of fructose-6-phosphate. - This reaction requires **ATP**, and like many enzymes that utilize ATP, PFK requires **magnesium ions (Mg²⁺)** as a cofactor, typically forming a complex with ATP (MgATP²⁻). *Inorganic phosphate* - **Inorganic phosphate** is a substrate for some kinase reactions, but not a direct cofactor requirement for the *activation* of phosphofructokinase itself. - While phosphate is incorporated into molecules during phosphorylation, it does not act as a metal ion cofactor to facilitate the enzyme's activity. *Manganese* - While **manganese (Mn²⁺)** can sometimes substitute for magnesium in certain enzyme reactions, it is not the primary or required cofactor for phosphofructokinase under normal physiological conditions. - Many enzymes have a preference for specific metal ions based on their active site structure and coordination chemistry. *Copper* - **Copper (Cu²⁺)** is a cofactor for a variety of enzymes, particularly those involved in **redox reactions** (e.g., cytochrome c oxidase, superoxide dismutase). - However, copper is not a required metallic cofactor for the activity of **phosphofructokinase** in glycolysis.
Question 93: What is the normal range of ferritin levels in adult males?
- A. 30-300 ng/ml (Correct Answer)
- B. 300-500 ng/ml
- C. 10-20 ng/ml
- D. 500-700 ng/ml
Explanation: ***30-300 ng/ml*** - The normal range for **ferritin levels** in adult males is typically **30-300 ng/ml** (some laboratories report 30-400 ng/ml). - Ferritin is an **iron storage protein**, and its levels reflect the body's iron stores. - Values below 30 ng/ml suggest **iron deficiency**, while values above 300 ng/ml may indicate iron overload or inflammatory conditions. *10-20 ng/ml* - These levels are **significantly low** and indicate **iron deficiency**. - This range is well below the normal threshold and would warrant investigation and likely iron supplementation. - Levels below 15 ng/ml are diagnostic of **iron deficiency** even in the absence of anemia. *300-500 ng/ml* - Levels in this range are considered **elevated** and can indicate iron overload, chronic inflammation, liver disease, or malignancy. - While some laboratories extend the upper limit to 400 ng/ml, persistent elevation above 300 ng/ml warrants further investigation. - Common causes include **hemochromatosis**, **chronic liver disease**, or **inflammatory conditions**. *500-700 ng/ml* - These levels are **significantly elevated** and strongly suggest **iron overload conditions** such as **hemochromatosis**, severe inflammatory states, or hepatocellular injury. - High ferritin levels can be associated with organ damage, leading to conditions like **cirrhosis** or **cardiomyopathy**. - Requires urgent investigation to identify the underlying cause.
Internal Medicine
1 questionsWhich of the following does not synthesize von Willebrand factor?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 91: Which of the following does not synthesize von Willebrand factor?
- A. Endothelial cells
- B. Hepatocytes (Correct Answer)
- C. Megakaryocytes
- D. None of the options
Explanation: ***Hepatocytes*** - Von Willebrand factor (vWF) is primarily synthesized by **endothelial cells** and **megakaryocytes** [1], not hepatocytes. - Hepatocytes are responsible for synthesizing other proteins like **clotting factors**, but not vWF. *Megakaryoctyes* - Megakaryocytes play a crucial role in the synthesis of **platelet-derived factors**, including von Willebrand factor (vWF) [1]. - They release vWF into the bloodstream, facilitating platelet adhesion, especially in vascular injury sites. *None* - The option implies all listed cell types synthesize vWF, which is incorrect, as **only endothelial cells and megakaryocytes** produce it [1]. - Suggests a misunderstanding of the synthesis of coagulation-related factors, as hepatocytes do not produce vWF. *Endothelial cells* - Endothelial cells are the primary source of **von Willebrand factor** [1], releasing it to assist in platelet aggregation and clotting. - They are essential for the body's response to vascular injury, facilitating hemostasis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 669-670.
Pharmacology
1 questionsWhich of the following is not an ionic receptor?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 91: Which of the following is not an ionic receptor?
- A. Kainate
- B. AMPA
- C. mGluR (Correct Answer)
- D. NMDA
Explanation: **Ionic receptors** (ionotropic receptors) are ligand-gated ion channels that open upon binding, allowing ions to flow directly through the channel. **Non-ionic receptors** (metabotropic receptors) are G-protein coupled receptors that activate intracellular signaling cascades. ***mGluR*** - **Metabotropic glutamate receptors (mGluRs)** are **G-protein coupled receptors** (GPCRs), meaning they activate intracellular signaling pathways rather than directly forming an ion channel. - Their activation leads to slower, longer-lasting changes in neuronal excitability through second messenger systems. - **This is the correct answer** as mGluRs are NOT ionic receptors. *NMDA* - **NMDA receptors** are **ionotropic glutamate receptors** that form ligand-gated ion channels permeable to calcium and sodium ions. - They are crucial for **synaptic plasticity** and learning. *Kainate* - **Kainate receptors** are also **ionotropic glutamate receptors** that are permeable to sodium and potassium ions. - They play diverse roles in synaptic transmission and neuronal excitability. *AMPA* - **AMPA receptors** are **ionotropic glutamate receptors** primarily responsible for fast excitatory synaptic transmission in the central nervous system. - They are permeable to sodium and potassium ions and mediate the majority of fast excitatory synaptic currents.
Physiology
2 questionsFemales have a lower RBC count compared to males due to?
ATPase activity is present in
NEET-PG 2013 - Physiology NEET-PG Practice Questions and MCQs
Question 91: Females have a lower RBC count compared to males due to?
- A. Low erythropoietin (Correct Answer)
- B. High estrogen
- C. Low stem cells
- D. Menstrual blood loss
Explanation: ***Low erythropoietin (relative to males)*** - The primary reason females have lower RBC counts is due to **hormonal differences**, specifically the lack of androgenic stimulation of erythropoiesis that males experience. - **Testosterone in males** directly stimulates erythropoietin production and enhances erythropoiesis, leading to higher RBC counts (males: 4.5-5.5 million/µL vs females: 4.0-5.0 million/µL). - Females have relatively lower erythropoietic drive compared to males due to the absence of significant androgenic hormones, which can be conceptualized as relatively lower erythropoietic stimulus. - This difference exists across all age groups, including pre-menarchal and post-menopausal women, confirming it is **hormonal rather than blood loss-related**. *High estrogen* - Estrogen does not significantly suppress erythropoiesis to cause lower RBC counts. - Estrogen has various effects on the hematopoietic system but is not the primary cause of the gender difference in RBC count. *Low stem cells* - Hematopoietic stem cell numbers and functionality are comparable between males and females. - There is no evidence of lower stem cell counts in females accounting for RBC differences. *Menstrual blood loss* - While menstrual blood loss can contribute to **iron deficiency anemia** in some women, it does NOT explain the baseline physiological difference in RBC counts between genders. - Most healthy menstruating women maintain normal RBC counts despite regular menstruation. - The RBC count difference exists even in pre-menarchal girls and post-menopausal women, proving menstruation is not the primary cause.
Question 92: ATPase activity is present in
- A. Myosin (Correct Answer)
- B. Actin
- C. Actin during interaction with myosin
- D. None of the options
Explanation: ***Myosin*** - Myosin heads possess intrinsic **ATPase activity**, meaning they can hydrolyze ATP into ADP and inorganic phosphate. - This **ATP hydrolysis** provides the energy required for the **power stroke** during muscle contraction, detaching the myosin head from actin. *Actin* - Actin filaments themselves do not have ATPase activity. - Actin's primary role is to form the **thin filaments** and bind to myosin heads during contraction. *Actin during interaction with myosin* - While actin interacts with myosin, it does not acquire ATPase activity. - The **myosin head**, not actin, is responsible for ATP hydrolysis during this interaction. *None of the options* - This option is incorrect because **myosin** clearly possesses ATPase activity, which is crucial for muscle function.