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The gold standard for diagnosing COVID-19 infection is RT-PCR because it detects viral RNA with high sensitivity and specificity. It can identify the virus even in early infection stages when viral loads are low, enabling accurate diagnosis. Unlike rapid antigen tests, which have lower sensitivity, RT-PCR minimizes false negatives. Imaging (like chest X-ray) and serology tests do not detect active infection but rather complications or immune response, respectively. Therefore, RT-PCR remains the most reliable method for confirming COVID-19 infection.

Reference: Harrison's Principles of Internal Medicine, Jameson et al., 20th Edition.
In compensated shock, the body activates physiological mechanisms like increased heart rate, vasoconstriction, and enhanced myocardial contractility to maintain adequate tissue perfusion. These compensations help sustain normal blood pressure despite decreased circulating volume or cardiac output. Hence, blood pressure remains within normal limits during this stage, preventing early detection solely by hypertension or hypotension. Only when these compensatory mechanisms fail does blood pressure drop, leading to decompensated shock. Monitoring these responses is crucial for timely surgical intervention.

Reference: Harrison's Principles of Internal Medicine, Fauci et al., 20th Edition.
Carcinomas are malignancies arising from epithelial cells, which line the surfaces of organs, glands, and body cavities. These cells form the majority of tissues in organs such as the skin, lungs, breasts, and gastrointestinal tract, making carcinomas the most common type of cancer encountered clinically. The epithelial origin explains their characteristic patterns of local invasion and potential to metastasize via lymphatics. Understanding this origin is crucial during surgical excision to ensure complete removal with clear margins and appropriate lymph node assessment. Proper identification guides prognosis and treatment planning.

Reference: Robbins Basic Pathology, Kumar et al., 10th Edition.
Ethylene oxide gas is considered a cold sterilization technique because it sterilizes medical instruments at low temperatures without the use of heat. This method is ideal for heat-sensitive devices that cannot withstand autoclaving or dry heat. It effectively kills all microorganisms, including spores, by alkylating proteins and DNA. Unlike autoclaving or dry heat, which require high temperatures, ethylene oxide preserves the integrity and functionality of delicate surgical instruments. Its ability to sterilize without heat makes it indispensable in modern surgical practice.

Reference: Medical Microbiology, Murray et al., 9th Edition.
The plasma membrane is primarily composed of phospholipids, which form a bilayer structure essential for membrane fluidity and selective permeability. This bilayer creates a hydrophobic barrier that regulates the entry and exit of substances, crucial for maintaining cellular homeostasis. Phospholipids provide the fundamental framework upon which proteins, cholesterol, and glycoproteins are integrated to assist specific functions like signaling and transport. In surgery, understanding this composition is vital for targeting membrane integrity and drug delivery systems. Disruption of the phospholipid bilayer can compromise cell viability and impact tissue repair.

Reference: Molecular Biology of the Cell, Alberts et al., 6th Edition.
Vitamin B12 is predominantly stored in the liver because it has a unique ability to bind to plasma proteins, allowing it to accumulate in significant amounts. The liver serves as the primary storage site, housing enough vitamin B12 to meet the body's needs for several years. This storage capacity is crucial because vitamin B12 absorption is complex and dependent on intrinsic factor, making continuous dietary intake less critical in the short term. Deficiencies often take years to manifest clinically due to these large hepatic stores. In contrast, vitamins like C and B6 are water-soluble and not stored extensively, and vitamin K is primarily involved in clotting with limited storage.

Reference: Harrison's Principles of Internal Medicine, Jameson et al., 20th Edition.
Deficiency of Galactose-1-phosphate uridyltransferase (GALT) is the primary cause of classic galactosemia. This enzyme is crucial for the proper metabolism of galactose, converting galactose-1-phosphate into UDP-galactose. Its deficiency leads to the accumulation of toxic substances such as galactose-1-phosphate in tissues, causing liver damage, jaundice, cataracts, and intellectual disability if untreated. Early diagnosis and dietary restriction of galactose are essential to prevent these severe complications.

Reference: Principles of Biochemistry, Nelson & Cox, 7th Edition.
The nucleic acid responsible for transporting amino acids to ribosomes during protein synthesis is tRNA (transfer RNA). tRNA molecules have specific anticodons that recognize codons on mRNA, ensuring the correct amino acid is delivered in sequence. This precise matching is critical for accurate protein assembly. Unlike mRNA, which carries the genetic code, or rRNA, which forms the ribosome's core, tRNA functions as the adaptor linking the genetic code to amino acids. This role is essential in translation, directly impacting protein structure and function, which is crucial in clinical scenarios involving genetic or translational defects.

Reference: Molecular Biology of the Cell, Bruce Alberts, 6th Edition.
The thyroid gland contains specialized cells called parafollicular cells (C cells) responsible for secreting calcitonin. Calcitonin plays a key role in lowering blood calcium levels by inhibiting osteoclast activity, thus reducing bone resorption. This hormone complements parathyroid hormone (PTH), which raises blood calcium levels. The parathyroid glands secrete PTH, not calcitonin. Recognizing the thyroid as the source of calcitonin is crucial in surgical procedures involving the neck to avoid inadvertent damage to the parafollicular cells affecting calcium homeostasis.

Reference: Gray’s Anatomy, Standring S, 42nd Edition.

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
The sympathetic nervous system originates specifically from the thoracolumbar region (T1-L2) of the spinal cord, where its preganglionic neurons are located in the lateral horn. This anatomical layout is crucial for understanding the distribution of sympathetic fibers and planning surgical interventions such as sympathectomy. Injuries or lesions outside this region typically do not affect sympathetic outflow directly. Knowledge of this region helps in avoiding damage to sympathetic pathways during spine or thoracic surgeries.

Reference: Gray's Anatomy, Standring S., 42nd Edition.
The alveoli are the primary sites of gas exchange in the lungs, marking them as the key components of the respiratory zone. This zone includes structures where oxygen and carbon dioxide diffuse between air and blood, crucial for effective respiration. In contrast, the trachea, bronchi, and terminal bronchioles belong to the conducting zone, responsible mainly for air transport and conditioning. Understanding the distinction is vital during surgical procedures involving lung resection or ventilation management to preserve or recognize functional lung tissue.

Reference: Gray's Anatomy, Richard L. Drake, 42nd Edition.
Systolic blood pressure is the maximum arterial pressure reached when the heart's ventricles contract and eject blood into the aorta. This phase is known as ventricular systole, and it reflects the force the heart generates to overcome arterial resistance. It is an essential measure to assess cardiac function and vascular health. Accurate understanding of systolic pressure helps in managing conditions like hypertension and guiding surgical decisions involving cardiovascular stability.
Reference: Guyton and Hall Textbook of Medical Physiology, John E. Hall, 14th Edition.
- The cephalic phase of gastric acid secretion is the initial phase that occurs even before food enters the stomach.
- This phase is primarily stimulated by the vagus nerve, which is part of the parasympathetic nervous system.
- When you see, smell, taste, or even think about food, the brain sends signals via the vagus nerve to the stomach, triggering the release of gastric acid and digestive enzymes in anticipation of food digestion.

- During this phase, the vagus nerve stimulates the parietal cells to secrete hydrochloric acid (HCl) indirectly by releasing acetylcholine, as well as promoting the release of gastrin and histamine, which further enhance acid secretion.

- In contrast, the gastric phase is stimulated by the presence of food in the stomach itself, and the intestinal phase involves the response to chyme entering the small intestine. The postprandial phase generally refers to the time after eating but is not specific to vagal stimulation.

Therefore, the primary stimulation via the vagus nerve occurs during the cephalic phase of gastric acid secretion.
The organ primarily responsible for the conversion of vitamin D into its active form is the kidneys. When vitamin D is obtained either from the skin (through sunlight exposure) or from dietary sources, it first undergoes hydroxylation in the liver to form 25-hydroxyvitamin D (calcidiol), which is the major circulating form. However, this form is still inactive.

The critical step for activation occurs in the kidneys, where the enzyme 1α-hydroxylase converts 25-hydroxyvitamin D into 1,25-dihydroxyvitamin D (calcitriol), the biologically active form of vitamin D. This active form is essential for regulating calcium and phosphate metabolism, promoting absorption of calcium in the intestines, and maintaining bone health.

To summarize:

- Vitamin D is initially hydroxylated in the liver to 25-hydroxyvitamin D.

- The kidneys carry out the second hydroxylation step, catalyzed by 1α-hydroxylase, forming active 1,25-dihydroxyvitamin D.

- This renal conversion is tightly regulated by factors such as parathyroid hormone (PTH), calcium, and phosphate levels.

Therefore, the correct answer is Kidneys.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th Edition, Chapter 76 - Calcium, Phosphorus, and Magnesium Metabolism
- The deficiency of the enzyme Hexosaminidase A is responsible for the development of Tay-Sachs disease.
- This is a rare, inherited neurodegenerative disorder characterized by the accumulation of GM2 ganglioside within the lysosomes of nerve cells.
- The absence or low activity of Hexosaminidase A leads to the inability to break down GM2 ganglioside, causing progressive destruction of neurons, which manifests as developmental delay, motor weakness, and eventually fatal neurological impairment.

Other enzymes mentioned, such as Sphingomyelinase, Galactocerebrosidase, and Arylsulfatase A, are deficient in different lysosomal storage diseases:
- Sphingomyelinase deficiency causes Niemann-Pick disease.
- Galactocerebrosidase deficiency is responsible for Krabbe disease.
- Arylsulfatase A deficiency leads to Metachromatic leukodystrophy.

Identifying the specific enzyme deficiency is crucial for accurate diagnosis and genetic counseling in affected families.

Reference: Robbins Basic Pathology, 10th Edition, Chapter on Diseases of Lysosomes/Page 521
- The Frank-Starling law describes the intrinsic ability of the heart to adjust its pumping function in response to changes in venous return or ventricular filling pressure.
- According to this law, an increase in the volume of blood filling the heart (end-diastolic volume) leads to a greater stretch of the ventricular muscle fibers.
- This stretch results in a more forceful contraction, thereby increasing the stroke volume — the amount of blood ejected with each heartbeat.

- In simple terms, the Frank-Starling mechanism ensures that the heart automatically balances its output with the amount of blood returning to it.
- This relationship is crucial for maintaining cardiac output under varying physiological conditions without relying solely on external regulatory systems.

Therefore, the law primarily illustrates the relationship between ventricular filling pressure (or preload) and stroke volume. It does not directly address heart rate, afterload, myocardial contractility, or arterial pressures.

Reference: Guyton and Hall Textbook of Medical Physiology, 13th Edition, Chapter 14, Page 164
- In Alzheimer's disease, the primary neurotransmitter that is decreased and leads to cognitive dysfunction is acetylcholine.
- This decrease occurs because of the degeneration of cholinergic neurons in the basal forebrain, particularly in the nucleus basalis of Meynert.
- Acetylcholine plays a critical role in learning, memory, and attention, which are commonly impaired in Alzheimer's patients.

- While other neurotransmitters like dopamine, norepinephrine, and serotonin may also be affected to some extent, the hallmark neurotransmitter deficit in Alzheimer's disease is the loss of acetylcholine.
- This understanding has led to the development of therapeutic agents, such as acetylcholinesterase inhibitors, aimed at increasing acetylcholine levels in the brain to improve cognitive symptoms.

Reference: Adams and Victor's Principles of Neurology, 11th Edition, Chapter 32 – Alzheimer's Disease / Page 482
- The glomerular filtration rate (GFR) is a crucial indicator of kidney function, representing the volume of fluid filtered from the renal glomerular capillaries into the Bowman's capsule per minute.
- In healthy adult individuals, the typical GFR range is approximately 120-130 mL/min.
- This value ensures that the kidneys efficiently filter blood to maintain fluid and electrolyte balance, remove waste products, and regulate blood pressure.

- GFR can vary slightly depending on factors such as age, sex, body size, and hydration status.
- However, values significantly below this range (e.g., less than 60 mL/min) may indicate renal impairment or chronic kidney disease.
- Conversely, values much higher than the normal range are uncommon in a healthy adult and may suggest hyperfiltration, which can be a response to various pathological states.

Therefore, the option "120-130 mL/min" accurately reflects the typical GFR range in a healthy adult.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th Edition, Chapter 26 / Page 310
- Trypsin is a pancreatic enzyme that specifically cleaves peptide bonds on the carboxyl side of basic amino acids, primarily arginine and lysine.
- This specificity is due to the structure of trypsin's active site, which contains a negatively charged aspartate residue that attracts and stabilizes the positively charged side chains of these basic amino acids.

To contrast:
- Chymotrypsin cleaves peptide bonds adjacent to aromatic amino acids such as phenylalanine, tyrosine, and tryptophan.
- Carboxypeptidase A is an exopeptidase that removes amino acids from the carboxyl terminus of proteins but prefers bulky hydrophobic residues rather than basic residues.
- Elastase cleaves peptide bonds adjacent to small, neutral amino acids like alanine.

Therefore, among the options, trypsin is the enzyme secreted by the pancreas that specifically targets peptide bonds next to basic amino acids.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th Edition, Chapter 65: Pancreatic Secretion, Page 849

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
- The oxygen-hemoglobin dissociation curve illustrates the relationship between the partial pressure of oxygen (pO2) and hemoglobin saturation.
- A rightward shift of this curve indicates that hemoglobin has a decreased affinity for oxygen, facilitating oxygen release to the tissues.

- Among the given options, elevated hydrogen ion concentration (lower pH) is the correct factor causing a rightward shift.
- This phenomenon is known as the Bohr effect, where increased H+ ions bind to hemoglobin and reduce its oxygen affinity.
- As a result, oxygen is more readily released in metabolically active tissues that have higher acidity.

In contrast, the other factors generally cause a leftward shift (increased oxygen affinity):
- Decreased 2,3-Bisphosphoglycerate (2,3-BPG) levels: 2,3-BPG binds to hemoglobin and lowers oxygen affinity; a decrease in 2,3-BPG increases affinity, causing a left shift.
- Reduced carbon dioxide levels: Low CO2 reduces H+ concentration, increasing hemoglobin’s oxygen affinity.
- Lowered body temperature: Cooler temperatures increase hemoglobin’s affinity for oxygen.

Therefore, the key point is that increased H+ concentration (lower pH) lowers hemoglobin’s affinity for oxygen, causing a rightward shift in the dissociation curve and promoting oxygen unloading in tissues needing it most.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th Edition, Chapter 35: Oxygen Transport
The primary precursor in the biosynthesis of serotonin is tryptophan. Serotonin is a neurotransmitter derived from the essential amino acid tryptophan through a two-step enzymatic process. First, tryptophan is hydroxylated by the enzyme tryptophan hydroxylase to form 5-hydroxytryptophan (5-HTP). Next, 5-HTP is decarboxylated by aromatic L-amino acid decarboxylase to produce serotonin (5-hydroxytryptamine or 5-HT).

In contrast, tyrosine and phenylalanine are mainly involved in the biosynthesis of catecholamines such as dopamine, norepinephrine, and epinephrine. Histidine serves as the precursor for histamine, another biologically important amine, but not serotonin.

Thus, understanding the distinct pathways of amino acid metabolism is crucial for grasping neurotransmitter biosynthesis and related physiological functions.

Reference: Lehninger Principles of Biochemistry, 7th Edition, Chapter 21: Signal Transduction and Neurotransmitter Biosynthesis
- The first heart sound (S1) is primarily caused by the closure of the atrioventricular (AV) valves, which include the mitral and tricuspid valves.
- During the cardiac cycle, after the atria contract and ventricular systole begins, the pressure within the ventricles rises sharply.
- This increase in pressure forces the AV valves to close, preventing the backflow of blood into the atria.

- The closure of these valves produces the characteristic “lub” sound, which is the first heart sound (S1).
- This sound marks the beginning of ventricular systole and the isovolumetric contraction phase.

In contrast:
- The closure of the semilunar valves produces the second heart sound (S2), not S1.
- The opening of the AV valves and semilunar valves is normally silent and does not produce heart sounds.

Therefore, the correct event responsible for producing the first heart sound (S1) is the closure of the atrioventricular valves.

Reference: Guyton and Hall Textbook of Medical Physiology, 13th Edition, Chapter 18: The Heart as a Pump and the Cardiac Cycle
- The primary source of NADPH required for fatty acid biosynthesis is the Pentose phosphate pathway.
- This biochemical pathway plays a crucial role in providing the reducing power necessary for anabolic reactions, such as the synthesis of fatty acids.

- During fatty acid biosynthesis, NADPH acts as a reducing agent, facilitating the conversion of acetyl-CoA into long-chain fatty acids.
- While glycolysis primarily generates ATP and pyruvate, it does not directly produce significant amounts of NADPH.
- The citric acid cycle focuses on energy production through NADH and FADH2, rather than NADPH generation. 
- Beta-oxidation, conversely, is involved in fatty acid degradation, producing NADH and FADH2 rather than NADPH.

- The Pentose phosphate pathway specifically generates NADPH through its oxidative phase, where glucose-6-phosphate is converted into ribulose-5-phosphate.
- This reaction involves the enzyme glucose-6-phosphate dehydrogenase, which reduces NADP+ to NADPH, making this pathway essential for biosynthetic processes.

Hence, the correct answer is the Pentose phosphate pathway, as it primarily supplies the NADPH needed for fatty acid biosynthesis.

Reference: Lehninger Principles of Biochemistry, 7th Edition, Chapter 22/Fatty Acid Metabolism
- The P wave on a standard ECG tracing represents atrial depolarization.
- This is the electrical activity associated with the contraction of the atria, which precedes the mechanical contraction and helps push blood into the ventricles.

- Specifically, the P wave reflects the spread of the electrical impulse from the sinoatrial (SA) node throughout the atrial myocardium.
- It is important to note that the P wave does not represent ventricular activity.

In contrast:
- Ventricular depolarization is represented by the QRS complex.
- Ventricular repolarization corresponds to the T wave.
- The AV node conduction delay is seen as the PR segment, the flat line between the end of the P wave and the beginning of the QRS complex.

Understanding the P wave is essential because abnormalities in its shape, size, or timing can indicate atrial enlargement or other atrial pathologies.

Reference: Robbins Basic Pathology, 10th Edition, Chapter on Cardiovascular Pathology, Page 435
The hormone that primarily promotes the production of red blood cells in the bone marrow is erythropoietin. Erythropoietin is a glycoprotein hormone mainly produced by the kidneys in response to low oxygen levels in the blood, a condition known as hypoxia. It acts by stimulating the proliferation and differentiation of erythroid progenitor cells in the bone marrow, leading to increased red blood cell (RBC) production. This process is crucial for maintaining adequate oxygen delivery to tissues throughout the body.

In contrast, thyroxine is involved mainly in regulating metabolism, growth hormone promotes overall body growth and development, and cortisol is a glucocorticoid that helps manage stress and inflammation but does not directly stimulate RBC production.

Therefore, erythropoietin is the hormone specifically responsible for red blood cell synthesis.

Reference: Guyton and Hall Textbook of Medical Physiology, 13th Edition, Chapter 16 / Page 190
- The most crucial buffer system in maintaining acid-base balance in human blood is the Bicarbonate buffer system (HCO₃⁻ / H₂CO₃).
- This system plays a vital role because it is the most efficient in neutralizing strong acids and bases in the blood, thus helping to maintain a stable pH close to the normal range of 7.35-7.45.

- The bicarbonate buffer system works by balancing the concentration of carbonic acid (H₂CO₃) and bicarbonate ions (HCO₃⁻).
- When an acid is introduced to the blood, bicarbonate ions react with the hydrogen ions (H⁺) to form carbonic acid, which then dissociates into water and carbon dioxide.

- This process is dynamic and reversible, allowing the respiratory system to regulate blood pH by adjusting the levels of CO2 through breathing.
- The kidneys also contribute by excreting or reabsorbing bicarbonate to maintain the acid-base balance.

- While other buffer systems such as the Phosphate buffer system (HPO₄²⁻ / H₂PO₄⁻), Protein buffer system (Hemoglobin and plasma proteins), and Ammonia buffer system (NH₃ / NH₄⁺) play secondary or localized roles, they are not as significant in the overall blood pH regulation as the bicarbonate system.

- In summary, the bicarbonate buffer system is essential because of its high buffering capacity, interaction with respiratory and renal systems, and its ability to effectively maintain the physiological pH of blood.

Reference: Guyton and Hall Textbook of Medical Physiology, 13th Edition, Chapter 26/Pages 333-337
In the renal nephron, different segments have varying permeability to water and solutes, which plays a crucial role in the kidney's ability to concentrate or dilute urine.

- The ascending limb of the loop of Henle is uniquely characterized by its impermeability to water under normal physiological conditions.
- This means that as the filtrate moves up this segment, water cannot follow the solutes by osmosis.
- Instead, the thick ascending limb actively reabsorbs ions such as sodium, potassium, and chloride, which helps to dilute the tubular fluid and contributes to the creation of a hyperosmotic medullary interstitium.

In contrast:
- The proximal convoluted tubule is highly permeable to water, allowing significant reabsorption of water alongside solutes.
- The distal convoluted tubule is relatively impermeable to water but can become permeable in the presence of antidiuretic hormone (ADH).
- The descending limb of the loop of Henle is permeable to water but not to solutes, allowing water to be reabsorbed and concentrating the tubular fluid.

Therefore, the ascending limb of the loop of Henle plays a critical role in creating the dilute tubular fluid necessary for urine concentration, by actively reabsorbing electrolytes while preventing water movement.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th Edition, Chapter 26 - Urine Formation by the Kidneys, Page 317-320
- The rate-limiting step in the biosynthesis of cholesterol is catalyzed by the enzyme HMG-CoA reductase.
- This enzyme converts HMG-CoA (3-hydroxy-3-methylglutaryl-CoA) into mevalonate, a crucial early step in the cholesterol synthesis pathway.
- Because this step controls the flux through the entire biosynthetic route, HMG-CoA reductase is tightly regulated by multiple mechanisms including feedback inhibition by cholesterol, phosphorylation by kinases, and control at the level of gene expression.
- This regulation ensures cellular cholesterol levels remain balanced.

In contrast, other enzymes listed serve different functions:
- Squalene synthase catalyzes a later step where two molecules of farnesyl pyrophosphate condense to form squalene.
- Acetyl-CoA carboxylase is involved in fatty acid synthesis, not cholesterol biosynthesis.
- Lanosterol demethylase participates in the demethylation of lanosterol during cholesterol synthesis, but this step occurs downstream of mevalonate formation and is not rate-limiting.

Therefore, HMG-CoA reductase represents the key regulatory and rate-limiting enzyme in cholesterol biosynthesis.

Reference: Harper’s Illustrated Biochemistry, 31st Edition, Chapter 23/Pages 478-480
- The primary cause of pernicious anemia is a deficiency of Vitamin B12 (cobalamin).
- This condition results from an autoimmune destruction of gastric parietal cells, which leads to a lack of intrinsic factor, a protein essential for the absorption of Vitamin B12 in the terminal ileum.
- Without intrinsic factor, Vitamin B12 cannot be adequately absorbed, leading to its deficiency.

- Vitamin B12 is crucial for DNA synthesis, particularly in red blood cell production.
- Its deficiency causes megaloblastic anemia, characterized by the presence of large, immature red blood cells.
- Pernicious anemia is a specific form of megaloblastic anemia caused primarily by impaired absorption of Vitamin B12 rather than inadequate dietary intake.

Other vitamins like Vitamin B6 (pyridoxine) and folic acid also play roles in hematopoiesis, but their deficiencies lead to different clinical presentations and are not the underlying cause of pernicious anemia. Vitamin C deficiency results in scurvy, which does not involve anemia of the pernicious type.

Reference: Harrison's Principles of Internal Medicine, 20th Edition, Chapter 117

ফ্রিতে ২ লাখ প্রশ্নের টপিক, সাব-টপিক ভিত্তিক ও ১০০০+ জব শুলুশন্স বিস্তারিতে ব্যাখ্যাসহ পড়তে ও আপনার পড়ার ট্র্যাকিং রাখতে সাইটে লগইন করুন।

লগইন করুন
- The citric acid cycle, also known as the Krebs cycle or TCA cycle, is a crucial metabolic pathway that plays a central role in cellular respiration. -
- It is the process by which acetyl-CoA is oxidized to produce energy carriers such as NADH and FADH2, which are essential for ATP production in the electron transport chain.

- The citric acid cycle takes place specifically in the mitochondrial matrix, which is the innermost compartment of the mitochondria.
- This location is important because the enzymes required for the cycle are all located within this matrix, allowing for efficient substrate channeling and interaction with other mitochondrial processes.

The other options are incorrect because:
Cytosol: The cytosol is where glycolysis occurs, not the citric acid cycle.
Endoplasmic reticulum: This organelle is primarily involved in protein and lipid synthesis.
Mitochondrial intermembrane space: This space is involved in the proton gradient formation necessary for ATP synthesis, but the citric acid cycle enzymes are not present here.

Therefore, the correct answer is mitochondrial matrix.

Reference: Lehninger Principles of Biochemistry, 7th Edition, Chapter 16, Page 610
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