Based on essential physiology and Guyton physiology textbook and any o

Based on essential physiology and Guyton physiology textbook( and any other) write in here, 550 mcq questions

Based on essential physiology and Guyton physiology textbook( and any other) write in here, 550 mcq based on the following topics. [Physiology Outline] 1. Cell and Introduction to Physiology 2. Blood and Body fluid Physiology 3. Autonomic Nervous System 4. Immune System 5. Excitable tissues (Nerves and Muscle physiology) 6. Cardiovascular system. 50% of the questions should not be single based answer ,rather they should have more than 1 answer,2 or 3 answers, 2 wrong anwers or no answer in the options, the options for these types of questions should have true or false after every option(for Example, "option A: deltoid muscle. True or false". Lastly the questions should be typed in different rows or paragraphs from the question not on the same row of the question, just like in CBT Exams

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Continuing from Question 487, completing the remaining 64 questions to reach 550. These continue the Cardiovascular System section and wrap up with a final review block.

SECTION 6: CARDIOVASCULAR SYSTEM (Continued)

Question 487

The Frank-Starling law of the heart states that:

A. Increased preload decreases stroke volume. True or False

B. Stroke volume increases as end-diastolic volume increases within physiological limits. True or False

C. The mechanism depends on the length-tension relationship of cardiac muscle. True or False

D. Increased afterload always augments cardiac output. True or False

Answers: B - True, C - True; A - False, D - False

Question 488

Which of the following correctly describes the cardiac action potential in ventricular myocytes?

A. Phase 0 is due to rapid Na⁺ influx. True or False

B. Phase 2 (plateau) is maintained by L-type Ca²⁺ channels. True or False

C. Phase 3 repolarization is due to K⁺ efflux. True or False

D. Phase 4 shows spontaneous depolarization in ventricular myocytes. True or False

Answers: A - True, B - True, C - True; D - False

Question 489

The normal resting cardiac output in an adult at rest is approximately:

A. 3 L/min

B. 5 L/min

C. 8 L/min

D. 10 L/min

Answer: B

Question 490

Regarding the jugular venous pulse (JVP) waveform, which of the following are correct?

A. The 'a' wave corresponds to atrial contraction. True or False

B. The 'c' wave is due to tricuspid valve closure. True or False

C. The 'v' wave represents ventricular systole with the tricuspid valve closed. True or False

D. The 'x' descent represents atrial filling. True or False

Answers: A - True, B - True, C - True; D - False (x descent = atrial relaxation + downward displacement of tricuspid valve)

Question 491

Which of the following statements about cardiac tamponade is correct?

A. It causes elevated jugular venous pressure.

B. It causes hypotension.

C. It causes muffled heart sounds.

D. All of the above.

Answer: D

Question 492

Regarding peripheral vascular resistance (PVR):

A. It is primarily determined by arterioles. True or False

B. PVR = (MAP - CVP) / Cardiac Output. True or False

C. Increased blood viscosity decreases PVR. True or False

D. Vasodilation increases PVR. True or False

Answers: A - True, B - True; C - False, D - False

Question 493

The QRS complex on the ECG represents:

A. Atrial depolarization

B. Ventricular depolarization

C. Ventricular repolarization

D. Atrial repolarization

Answer: B

Question 494

Regarding the baroreceptor reflex:

A. Baroreceptors are located in the carotid sinus and aortic arch. True or False

B. Increased blood pressure activates baroreceptors and increases heart rate. True or False

C. The afferent signals travel via the glossopharyngeal (IX) and vagus (X) nerves. True or False

D. The baroreceptor reflex is a long-term regulator of blood pressure. True or False

Answers: A - True, C - True; B - False (increased BP decreases HR via baroreceptor reflex), D - False (short-term regulator)

Question 495

The refractory period of cardiac muscle compared to skeletal muscle:

A. Is much shorter in cardiac muscle

B. Is much longer in cardiac muscle, preventing tetanus

C. Is the same in both

D. Has no functional significance

Answer: B

Question 496

Which of the following regarding coronary blood flow are TRUE?

A. The left coronary artery perfuses the myocardium predominantly during diastole. True or False

B. Coronary blood flow is primarily regulated by local metabolic factors. True or False

C. Adenosine is a potent coronary vasodilator released during ischemia. True or False

D. Increased heart rate increases myocardial oxygen demand without affecting coronary flow. True or False

Answers: A - True, B - True, C - True; D - False

Question 497

In mitral stenosis, which haemodynamic change is expected?

A. Elevated left atrial pressure

B. Reduced pulmonary venous pressure

C. Increased left ventricular filling

D. Decreased pulmonary arterial pressure

Answer: A

Question 498

Regarding Starling's forces in capillary fluid exchange:

A. Capillary hydrostatic pressure favors filtration. True or False

B. Plasma oncotic pressure opposes filtration. True or False

C. Interstitial fluid oncotic pressure favors reabsorption. True or False

D. Net filtration pressure at the venous end is normally positive, favoring filtration. True or False

Answers: A - True, B - True; C - False (favors filtration), D - False (favors reabsorption at venous end)

Question 499

The P-R interval on the ECG represents:

A. Time for ventricular depolarization

B. Time for the impulse to travel from SA node through the AV node to the bundle of His

C. Duration of ventricular systole

D. Time for atrial repolarization

Answer: B

Question 500

Which of the following are features of heart failure with reduced ejection fraction (HFrEF)?

A. Ejection fraction less than 40%. True or False

B. Increased end-diastolic volume. True or False

C. Activation of the renin-angiotensin-aldosterone system. True or False

D. Decreased sympathetic nervous system activity. True or False

Answers: A - True, B - True, C - True; D - False

Question 501

The mitral valve opens when:

A. Left atrial pressure exceeds left ventricular pressure

B. Left ventricular pressure exceeds aortic pressure

C. The QRS complex begins on ECG

D. Isovolumetric contraction begins

Answer: A

Question 502

Regarding blood pressure regulation by the kidneys:

A. The kidney regulates long-term blood pressure via pressure natriuresis. True or False

B. Increased renal perfusion pressure leads to increased sodium and water excretion. True or False

C. Renal autoregulation maintains GFR constant between 80-180 mmHg MAP. True or False

D. Aldosterone promotes sodium excretion, lowering blood pressure. True or False

Answers: A - True, B - True, C - True; D - False (aldosterone promotes sodium retention)

Question 503

The Fick principle for measuring cardiac output states that:

A. Cardiac output = O₂ consumption / (arterial O₂ content - venous O₂ content)

B. Cardiac output = (arterial O₂ - venous O₂) / O₂ consumption

C. Cardiac output = stroke volume × heart rate × ejection fraction

D. Cardiac output = mean arterial pressure / systemic vascular resistance

Answer: A

Question 504

Regarding the sinoatrial (SA) node:

A. It has the fastest spontaneous rate of depolarization in the heart. True or False

B. It is located at the junction of the superior vena cava and right atrium. True or False

C. Its action potential shows a prominent phase 2 plateau. True or False

D. Vagal stimulation increases SA node firing rate. True or False

Answers: A - True, B - True; C - False (no prominent plateau), D - False (vagal stimulation decreases rate)

Question 505

During isovolumetric contraction:

A. Both mitral and aortic valves are closed

B. The aortic valve is open and mitral valve is closed

C. Both valves are open

D. The mitral valve is open and aortic valve is closed

Answer: A

Question 506

Which of the following describe the Windkessel effect of the aorta?

A. The elastic aorta stores energy during systole. True or False

B. During diastole, elastic recoil maintains diastolic blood pressure. True or False

C. Loss of aortic compliance increases pulse pressure. True or False

D. The Windkessel effect reduces the work of the heart. True or False

Answers: A - True, B - True, C - True, D - True

Question 507

A 60-year-old patient has a pulse pressure of 80 mmHg. Which condition is most consistent?

A. Aortic stenosis

B. Aortic regurgitation

C. Mitral stenosis

D. Cardiac tamponade

Answer: B

Question 508

Regarding venous return to the heart:

A. The skeletal muscle pump assists venous return. True or False

B. Increased intrathoracic pressure during inspiration facilitates venous return. True or False

C. Venous valves prevent retrograde flow. True or False

D. Increased venous compliance decreases venous return. True or False

Answers: A - True, C - True, D - True; B - False (decreased intrathoracic pressure during inspiration facilitates venous return)

Question 509

The normal cardiac ejection fraction is approximately:

A. 30-40%

B. 55-70%

C. 80-90%

D. 20-30%

Answer: B

Question 510

Which of the following correctly describe cardiac preload?

A. Preload is the end-diastolic volume or pressure. True or False

B. Preload is determined by venous return. True or False

C. Increased preload increases stroke volume via the Frank-Starling mechanism. True or False

D. Preload is the tension in the ventricular wall after valve opening. True or False

Answers: A - True, B - True, C - True; D - False (that describes afterload)

Question 511

The first heart sound (S1) is caused by:

A. Closure of the aortic and pulmonary valves

B. Closure of the mitral and tricuspid valves

C. Opening of the mitral valve

D. Ventricular filling turbulence

Answer: B

Question 512

Regarding cardiac afterload:

A. Afterload is the resistance against which the ventricle must eject blood. True or False

B. Increased afterload increases stroke volume. True or False

C. Systemic vascular resistance is the main determinant of left ventricular afterload. True or False

D. Pulmonary vascular resistance determines right ventricular afterload. True or False

Answers: A - True, C - True, D - True; B - False (increased afterload decreases stroke volume)

Question 513

Which of the following are mechanisms of autoregulation of blood flow?

A. Myogenic mechanism - arterioles contract when stretched. True or False

B. Metabolic mechanism - local metabolites cause vasodilation. True or False

C. Tubuloglomerular feedback in the kidney. True or False

D. Baroreceptor reflex is a form of local autoregulation. True or False

Answers: A - True, B - True, C - True; D - False (baroreceptors are systemic neural regulation)

Question 514

Regarding the T wave on the ECG:

A. It represents ventricular repolarization.

B. It is normally inverted in lead aVR.

C. Hyperkalemia can cause tall, peaked T waves.

D. All of the above.

Answer: D

Question 515

The mean arterial pressure (MAP) is best calculated as:

A. (Systolic BP + Diastolic BP) / 2

B. Diastolic BP + 1/3 Pulse Pressure

C. Systolic BP - Diastolic BP

D. 2/3 Systolic BP + 1/3 Diastolic BP

Answer: B

Question 516

Which of the following are correct regarding the lymphatic system?

A. Lymph vessels drain excess interstitial fluid back to the circulation. True or False

B. Lymph ultimately drains into the subclavian veins. True or False

C. Lymph flow is assisted by smooth muscle contractions of lymph vessels. True or False

D. Increased capillary permeability decreases lymph flow. True or False

Answers: A - True, B - True, C - True; D - False

Question 517

The atrioventricular (AV) node delay serves what physiological purpose?

A. It prevents atrial fibrillation.

B. It allows time for ventricular filling before ventricular contraction.

C. It increases cardiac output directly.

D. It prevents retrograde conduction.

Answer: B

Question 518

Regarding the microcirculation:

A. Precapillary sphincters regulate flow through capillary beds. True or False

B. True capillaries lack smooth muscle. True or False

C. Metarterioles connect arterioles directly to venules, bypassing capillaries. True or False

D. Vasomotion refers to rhythmic contraction and relaxation of arterioles. True or False

Answers: A - True, B - True, C - True, D - True

Question 519

In complete heart block (third-degree AV block):

A. P waves and QRS complexes are dissociated

B. Ventricular rate equals atrial rate

C. P waves are absent

D. All QRS complexes follow P waves with fixed interval

Answer: A

Question 520

Which of the following correctly describe the effects of sympathetic stimulation on the heart?

A. Increases heart rate (positive chronotropy). True or False

B. Increases contractility (positive inotropy). True or False

C. Shortens conduction time through AV node. True or False

D. Decreases cardiac output. True or False

Answers: A - True, B - True, C - True; D - False

Question 521

The normal PR interval duration is:

A. 0.04-0.08 seconds

B. 0.12-0.20 seconds

C. 0.30-0.40 seconds

D. 0.50-0.60 seconds

Answer: B

Question 522

Which of the following are local vasodilatory substances?

A. Nitric oxide (NO). True or False

B. Adenosine. True or False

C. Endothelin-1. True or False

D. Prostacyclin (PGI₂). True or False

Answers: A - True, B - True, D - True; C - False (endothelin-1 is a potent vasoconstrictor)

Question 523

The plateau phase (Phase 2) of the ventricular action potential is unique because:

A. It allows calcium entry that triggers contraction

B. It prevents summation and tetanus of cardiac muscle

C. It prolongs the refractory period

D. All of the above

Answer: D

Question 524

Regarding right heart catheterization pressures, which values are NORMAL?

A. Right atrial pressure: 0-8 mmHg. True or False

B. Pulmonary artery pressure: 25/10 mmHg. True or False

C. Pulmonary capillary wedge pressure (PCWP): 20-25 mmHg. True or False

D. Right ventricular systolic pressure: 15-30 mmHg. True or False

Answers: A - True, B - True, D - True; C - False (normal PCWP = 6-12 mmHg)

Question 525

The velocity of blood flow in different vessels is SLOWEST in:

A. Aorta

B. Large arteries

C. Capillaries

D. Veins

Answer: C

Question 526

Regarding cardiac glycosides (e.g., digoxin):

A. They inhibit Na⁺/K⁺-ATPase pump. True or False

B. They increase intracellular calcium concentration. True or False

C. They decrease heart rate by enhancing vagal tone. True or False

D. They are used to increase contractility in heart failure. True or False

Answers: A - True, B - True, C - True, D - True

Question 527

A patient has blood pressure of 180/110 mmHg. Their pulse pressure is:

A. 145 mmHg

B. 70 mmHg

C. 110 mmHg

D. 180 mmHg

Answer: B (180 - 110 = 70 mmHg)

Question 528

Regarding the arterial blood pressure waveform, which of the following are correct?

A. The dicrotic notch corresponds to aortic valve closure. True or False

B. The upstroke reflects ventricular ejection. True or False

C. The incisura marks the beginning of ventricular filling. True or False

D. Pulse pressure is the difference between systolic and diastolic pressures. True or False

Answers: A - True, B - True, D - True; C - False (incisura/dicrotic notch marks end of ejection/beginning of diastole)

Question 529

Which of the following conditions increases cardiac output?

A. Anaemia

B. Thyrotoxicosis

C. Arteriovenous fistula

D. All of the above

Answer: D

Question 530

Regarding the pressure-volume (PV) loop of the left ventricle:

A. The width of the PV loop represents stroke volume. True or False

B. The area enclosed by the PV loop represents stroke work. True or False

C. Increased afterload shifts the end-systolic pressure-volume point to the right. True or False

D. Increased preload increases end-diastolic volume and shifts the loop to the right. True or False

Answers: A - True, B - True, C - True, D - True

Question 531

Atrial natriuretic peptide (ANP) is released in response to:

A. Atrial stretch due to increased blood volume

B. Decreased blood pressure

C. Hyponatremia

D. Sympathetic stimulation

Answer: A

Question 532

Which of the following are effects of ANP?

A. Vasodilation. True or False

B. Increased GFR. True or False

C. Inhibition of aldosterone secretion. True or False

D. Increased sodium reabsorption in collecting duct. True or False

Answers: A - True, B - True, C - True; D - False (ANP inhibits sodium reabsorption)

Question 533

The normal QRS duration is:

A. Less than 0.06 seconds

B. Less than 0.12 seconds

C. 0.20-0.30 seconds

D. 0.40-0.50 seconds

Answer: B

Question 534

Regarding the electrical axis of the heart, left axis deviation (LAD) is defined as an axis of:

A. 0° to +90°

B. -30° to -90°

C. +90° to +180°

D. 0° to -30°

Answer: B

Question 535

Which of the following statements about the pericardium are correct?

A. It prevents overdistension of the cardiac chambers. True or False

B. It reduces friction between the heart and surrounding structures. True or False

C. The pericardial space normally contains 15-50 mL of fluid. True or False

D. The fibrous pericardium is highly elastic and easily distensible. True or False

Answers: A - True, B - True, C - True; D - False (fibrous pericardium is inelastic)

Question 536

Regarding the carotid body chemoreceptors:

A. They respond to decreases in arterial PO₂ below 60 mmHg. True or False

B. They respond to increases in arterial PCO₂. True or False

C. They respond to decreases in pH. True or False

D. Stimulation causes cardiovascular inhibition. True or False

Answers: A - True, B - True, C - True; D - False (stimulation causes vasoconstriction and cardiovascular activation)

Question 537

The venous system contains approximately what percentage of the total blood volume?

A. 10-15%

B. 20-25%

C. 60-70%

D. 80-90%

Answer: C

Question 538

Regarding shock states, which of the following are correctly matched?

A. Hypovolemic shock - decreased preload. True or False

B. Cardiogenic shock - decreased cardiac output with elevated filling pressures. True or False

C. Distributive shock - decreased systemic vascular resistance. True or False

D. Obstructive shock - increased preload with normal cardiac contractility. True or False

Answers: A - True, B - True, C - True; D - False (obstructive shock has decreased preload/filling due to obstruction)

Question 539

Which of the following are correct regarding nitric oxide (NO) in vascular physiology?

A. NO is synthesized from L-arginine by nitric oxide synthase. True or False

B. NO causes smooth muscle relaxation via cGMP. True or False

C. Endothelial shear stress stimulates NO production. True or False

D. NO promotes platelet aggregation and thrombosis. True or False

Answers: A - True, B - True, C - True; D - False (NO inhibits platelet aggregation)

Question 540

During the cardiac cycle, end-systolic volume (ESV) is approximately:

A. 120-130 mL

B. 70-80 mL

C. 40-50 mL

D. 10-20 mL

Answer: C

Question 541

Regarding Poiseuille's Law applied to blood flow:

A. Flow is proportional to the fourth power of vessel radius. True or False

B. Flow is inversely proportional to vessel length. True or False

C. Flow is inversely proportional to blood viscosity. True or False

D. Doubling the vessel radius increases flow by a factor of 16. True or False

Answers: A - True, C - True, D - True; B - False (flow is inversely proportional to length)

Question 542

Which of the following represents turbulent blood flow?

A. High Reynolds number (>2000)

B. Low velocity

C. Small vessel diameter

D. Low blood viscosity

Answer: A

Question 543

Regarding the effects of exercise on the cardiovascular system:

A. Cardiac output can increase up to 5 times resting values. True or False

B. Skeletal muscle vasodilation reduces total peripheral resistance. True or False

C. Heart rate increases due to sympathetic stimulation and vagal withdrawal. True or False

D. Stroke volume decreases during maximal exercise. True or False

Answers: A - True, B - True, C - True; D - False (stroke volume increases during exercise)

Question 544

The P wave on the ECG corresponds to:

A. Ventricular depolarization

B. Atrial depolarization

C. Atrial repolarization

D. AV nodal conduction

Answer: B

Question 545

Which of the following are TRUE regarding pulmonary circulation?

A. It is a low-pressure, high-flow system. True or False

B. Normal pulmonary artery systolic pressure is 15-30 mmHg. True or False

C. Hypoxia causes pulmonary vasoconstriction (HPV). True or False

D. Pulmonary vascular resistance is higher than systemic vascular resistance. True or False

Answers: A - True, B - True, C - True; D - False (pulmonary vascular resistance is much lower)

Question 546

Regarding atrial fibrillation (AF):

A. AF is characterized by absent P waves and irregularly irregular rhythm. True or False

B. Atrial rate in AF is 350-600 bpm. True or False

C. AF is a risk factor for systemic thromboembolism. True or False

D. AF is associated with a regular ventricular rate. True or False

Answers: A - True, B - True, C - True; D - False (ventricular rate is irregularly irregular in AF)

Question 547

The cardiac index is defined as:

A. Stroke volume divided by heart rate

B. Cardiac output divided by body surface area

C. Heart rate multiplied by ejection fraction

D. Mean arterial pressure divided by heart rate

Answer: B

Question 548

Which of the following correctly describe the renin-angiotensin-aldosterone system (RAAS) in blood pressure control?

A. Renin is secreted by juxtaglomerular cells in response to decreased renal perfusion. True or False

B. Angiotensin II causes vasoconstriction and aldosterone release. True or False

C. Aldosterone promotes sodium retention and potassium excretion. True or False

D. ACE inhibitors block the conversion of angiotensin I to angiotensin II. True or False

Answers: A - True, B - True, C - True, D - True

Question 549

A patient with aortic stenosis would be expected to have:

A. Increased pulse pressure

B. Slow-rising, low-amplitude pulse (pulsus parvus et tardus)

C. Wide pulse pressure

D. Bounding pulse

Answer: B

Question 550

Regarding the integrated control of cardiovascular function, which of the following statements are CORRECT?

A. The medullary cardiovascular centre integrates neural, hormonal, and local signals. True or False

B. The vasomotor centre in the medulla controls vascular tone via sympathetic outflow. True or False

C. The cardioinhibitory centre increases heart rate via vagal activation. True or False

D. Long-term blood pressure control is primarily determined by renal fluid balance mechanisms. True or False

Answers: A - True, B - True, D - True; C - False (cardioinhibitory centre decreases heart rate via vagal activation)

COMPLETE ANSWER KEY SUMMARY (Questions 487-550)

Q	Answer	Q	Answer
487	B, C True; A, D False	519	A
488	A, B, C True; D False	520	A, B, C True; D False
489	B	521	B
490	A, B, C True; D False	522	A, B, D True; C False
491	D	523	D
492	A, B True; C, D False	524	A, B, D True; C False
493	B	525	C
494	A, C True; B, D False	526	A, B, C, D True
495	B	527	B
496	A, B, C True; D False	528	A, B, D True; C False
497	A	529	D
498	A, B True; C, D False	530	A, B, C, D True
499	B	531	A
500	A, B, C True; D False	532	A, B, C True; D False
501	A	533	B
502	A, B, C True; D False	534	B
503	A	535	A, B, C True; D False
504	A, B True; C, D False	536	A, B, C True; D False
505	A	537	C
506	A, B, C, D True	538	A, B, C True; D False
507	B	539	A, B, C True; D False
508	A, C, D True; B False	540	C
509	B	541	A, C, D True; B False
510	A, B, C True; D False	542	A
511	B	543	A, B, C True; D False
512	A, C, D True; B False	544	B
513	A, B, C True; D False	545	A, B, C True; D False
514	D	546	A, B, C True; D False
515	B	547	B
516	A, B, C True; D False	548	A, B, C, D True
517	B	549	B
518	A, B, C, D True	550	A, B, D True; C False

All 550 questions are now complete, drawn from Guyton & Hall Textbook of Medical Physiology, Ganong's Review of Medical Physiology, Costanzo Physiology, and Essential Physiology principles, covering:

Topic 1 - Cell & Introduction to Physiology: Qs 1-90
Topic 2 - Blood & Body Fluid Physiology: Qs 91-180
Topic 3 - Autonomic Nervous System: Qs 181-270
Topic 4 - Immune System: Qs 271-360
Topic 5 - Excitable Tissues (Nerves & Muscle): Qs 361-450
Topic 6 - Cardiovascular System: Qs 451-550

Make a pdf containing all the questions from 1 to 550

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Based on textbook of biochemistry for medical students by Vm vasudevan and any other medical students Biochemistry textbook, write in here 600 MCQ questions based on the following topics. [Biochemistry outline] 1. Fluid and electrolytes, Disorders of fluid and electrolytes balance 2. Amino acids chemistry 3. Carbohydrate chemistry 4. Lipid chemistry 5. Nucleic acid chemistry 6. Immunology 7. Muscle Biochemistry and metabolism 8. Protein and Amino acid metabolism 9. Carbohydrate metabolism 10. Lipid metabolism 11. Nucleic acid metabolism 12. Cell. Some of questions should not be single based answer( about 25% per topic),rather they should have more than 1 answer or no answer in the options, the options for these types of questions should have true or false after every option(for Example, "option A: deltoid muscle. True or false". Lastly the questions should be typed in different rows or paragraphs from the question not on the same row of the question, just like in CBT Exams

Finding Sources

You stopped at question 515, please continue

Continuing from Question 516, completing the remaining 85 questions to reach 600. These continue Nucleic Acid Metabolism, then complete Cell Biochemistry.

TOPIC 11: NUCLEIC ACID METABOLISM (Continued)

Question 516

The enzyme that removes RNA primers during DNA replication in eukaryotes is:

A. DNA Polymerase I

B. DNA Polymerase delta (δ)

C. RNase H and FEN1

D. DNA ligase

Answer: C

Question 517

Regarding telomeres and telomerase, which of the following are TRUE?

A. Telomeres are repetitive TTAGGG sequences at chromosome ends. True or False

B. Telomerase is a reverse transcriptase that uses an RNA template. True or False

C. Telomerase activity is high in somatic cells and low in cancer cells. True or False

D. Shortening of telomeres is associated with cellular aging. True or False

Answers: A - True, B - True, D - True; C - False (telomerase is high in cancer cells and germ cells, low in somatic cells)

Question 518

Which of the following base pairs is found in DNA?

A. Adenine - Uracil

B. Guanine - Cytosine

C. Adenine - Thymine

D. Both B and C

Answer: D

Question 519

Regarding transcription in eukaryotes:

A. RNA Polymerase I transcribes ribosomal RNA (rRNA). True or False

B. RNA Polymerase II transcribes mRNA. True or False

C. RNA Polymerase III transcribes tRNA and 5S rRNA. True or False

D. All eukaryotic RNA polymerases require a sigma factor for promoter recognition. True or False

Answers: A - True, B - True, C - True; D - False (sigma factor is prokaryotic; eukaryotes use general transcription factors)

Question 520

The Shine-Dalgarno sequence is:

A. A eukaryotic enhancer element

B. A prokaryotic ribosome binding site on mRNA

C. A sequence involved in polyadenylation

D. A splice donor site

Answer: B

Question 521

Which of the following are post-transcriptional modifications of eukaryotic mRNA?

A. 5' capping with 7-methylguanosine. True or False

B. 3' polyadenylation. True or False

C. Splicing out of introns. True or False

D. Addition of a Shine-Dalgarno sequence. True or False

Answers: A - True, B - True, C - True; D - False (Shine-Dalgarno is prokaryotic)

Question 522

The codon AUG codes for which amino acid and also serves as:

A. Leucine; stop codon

B. Methionine; start codon

C. Valine; initiation factor

D. Phenylalanine; start codon

Answer: B

Question 523

Which of the following statements about the genetic code are correct?

A. It is degenerate - multiple codons can code for the same amino acid. True or False

B. It is unambiguous - each codon codes for only one amino acid. True or False

C. It is non-overlapping in standard reading. True or False

D. UAA, UAG, and UGA are the three stop codons. True or False

Answers: A - True, B - True, C - True, D - True

Question 524

Xeroderma pigmentosum is caused by a defect in:

A. Base excision repair

B. Nucleotide excision repair (NER)

C. Mismatch repair

D. Non-homologous end joining

Answer: B

Question 525

Regarding reverse transcriptase:

A. It synthesizes DNA from an RNA template. True or False

B. It is found in retroviruses such as HIV. True or False

C. It requires a DNA primer to initiate synthesis. True or False

D. It has both DNA polymerase and RNase H activity. True or False

Answers: A - True, B - True, D - True; C - False (it uses an RNA primer - tRNA)

Question 526

The process by which a ribosome moves along mRNA during translation is called:

A. Initiation

B. Elongation

C. Translocation

D. Termination

Answer: C

Question 527

Which enzyme is responsible for joining Okazaki fragments during DNA replication?

A. DNA Polymerase III

B. Primase

C. DNA Ligase

D. Helicase

Answer: C

Question 528

Regarding microRNA (miRNA):

A. miRNA is a small non-coding RNA of about 22 nucleotides. True or False

B. miRNA silences gene expression by binding complementary mRNA sequences. True or False

C. miRNA is processed from a hairpin precursor by Dicer. True or False

D. miRNA directly degrades DNA to suppress gene expression. True or False

Answers: A - True, B - True, C - True; D - False (miRNA targets mRNA, not DNA)

Question 529

The anticodon of a tRNA that reads the codon 5'-AUG-3' would be:

A. 5'-CAU-3'

B. 5'-UAC-3'

C. 5'-GUA-3'

D. 5'-AUG-3'

Answer: A (anticodon is antiparallel and complementary: 3'-UAC-5' written as 5'-CAU-3')

Question 530

Which of the following drugs inhibit DNA gyrase (topoisomerase II) in bacteria?

A. Rifampicin

B. Fluoroquinolones (e.g., ciprofloxacin)

C. Aminoglycosides

D. Beta-lactams

Answer: B

Question 531

Regarding purine synthesis de novo:

A. The purine ring is built on ribose-5-phosphate. True or False

B. Glutamine, glycine, aspartate, and CO₂ contribute atoms to the purine ring. True or False

C. PRPP (phosphoribosyl pyrophosphate) is the activated form of ribose. True or False

D. De novo purine synthesis occurs primarily in the mitochondria. True or False

Answers: A - True, B - True, C - True; D - False (occurs in the cytosol)

Question 532

Gout is caused by:

A. Decreased uric acid production

B. Hyperuricemia due to excess purine catabolism or decreased excretion

C. Pyrimidine accumulation

D. Deficiency of adenosine deaminase

Answer: B

Question 533

Which enzyme is deficient in Lesch-Nyhan syndrome?

A. Adenosine deaminase (ADA)

B. Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)

C. Xanthine oxidase

D. Purine nucleoside phosphorylase

Answer: B

Question 534

Regarding pyrimidine synthesis:

A. The pyrimidine ring is synthesized before attachment to ribose-5-phosphate. True or False

B. Carbamoyl phosphate synthetase II (CPS II) is the regulated step in cytosol. True or False

C. UTP is synthesized before CTP in the pyrimidine pathway. True or False

D. Orotic aciduria results from a defect in HGPRT enzyme. True or False

Answers: A - True, B - True, C - True; D - False (orotic aciduria results from UMP synthase deficiency)

Question 535

The PCR (Polymerase Chain Reaction) technique uses:

A. RNA polymerase for amplification

B. Thermostable DNA polymerase (Taq polymerase)

C. Reverse transcriptase for all types

D. RNA as the template in all applications

Answer: B

Question 536

Which of the following are steps in PCR?

A. Denaturation at ~94°C to separate DNA strands. True or False

B. Annealing of primers at ~50-65°C. True or False

C. Extension by DNA polymerase at ~72°C. True or False

D. Ligation of Okazaki fragments after each cycle. True or False

Answers: A - True, B - True, C - True; D - False

Question 537

A mutation that changes a codon from GAG (Glu) to GTG (Val) causing sickle cell disease is an example of:

A. Nonsense mutation

B. Silent mutation

C. Missense mutation

D. Frameshift mutation

Answer: C

Question 538

Regarding DNA methylation in epigenetics:

A. Methylation of CpG islands in promoters typically silences gene expression. True or False

B. DNA methylation is catalyzed by DNA methyltransferases (DNMTs). True or False

C. Hypermethylation of tumor suppressor gene promoters is seen in cancer. True or False

D. DNA methylation permanently removes the methyl group and cannot be reversed. True or False

Answers: A - True, B - True, C - True; D - False (demethylation can occur via TET enzymes)

Question 539

Which of the following correctly describes Western blotting?

A. Detects specific DNA sequences

B. Detects specific RNA sequences

C. Detects specific proteins using antibodies

D. Measures protein synthesis rates

Answer: C

Question 540

Regarding CRISPR-Cas9:

A. It uses guide RNA (gRNA) to direct Cas9 to a specific DNA sequence. True or False

B. Cas9 is an endonuclease that creates double-strand breaks in DNA. True or False

C. CRISPR-Cas9 can only delete genes but cannot insert new sequences. True or False

D. It was originally discovered as a bacterial adaptive immune system. True or False

Answers: A - True, B - True, D - True; C - False (it can both delete and insert sequences)

TOPIC 12: CELL BIOCHEMISTRY

Question 541

The fluid mosaic model of the cell membrane was proposed by:

A. Watson and Crick

B. Singer and Nicolson

C. Davson and Danielli

D. Krebs and Kornberg

Answer: B

Question 542

Which of the following lipids are components of the cell membrane?

A. Phosphatidylcholine. True or False

B. Sphingomyelin. True or False

C. Cholesterol. True or False

D. Triacylglycerol (triglyceride). True or False

Answers: A - True, B - True, C - True; D - False (TAG is a storage lipid, not a membrane component)

Question 543

The primary role of cholesterol in the cell membrane is to:

A. Provide energy storage

B. Modulate membrane fluidity and rigidity

C. Serve as a receptor for hormones

D. Transport ions across the membrane

Answer: B

Question 544

Regarding membrane transport:

A. Simple diffusion requires no energy and moves solutes down their concentration gradient. True or False

B. Active transport requires ATP and moves solutes against their concentration gradient. True or False

C. Facilitated diffusion uses carrier proteins but requires no ATP. True or False

D. Osmosis is the movement of solutes across a semipermeable membrane. True or False

Answers: A - True, B - True, C - True; D - False (osmosis is the movement of water, not solutes)

Question 545

The Na⁺/K⁺-ATPase pump:

A. Pumps 3 Na⁺ out and 2 K⁺ into the cell per cycle

B. Pumps 2 Na⁺ out and 3 K⁺ into the cell per cycle

C. Uses GTP as the energy source

D. Moves both ions down their concentration gradients

Answer: A

Question 546

Which of the following are features of the mitochondrion?

A. It has a double membrane system with inner and outer membranes. True or False

B. The inner membrane is highly folded into cristae. True or False

C. The mitochondrial matrix contains its own DNA (circular). True or False

D. The outer mitochondrial membrane is impermeable to all small molecules. True or False

Answers: A - True, B - True, C - True; D - False (the outer membrane is permeable to small molecules via porins; the inner membrane is selectively impermeable)

Question 547

The smooth endoplasmic reticulum (SER) is involved in:

A. Protein synthesis

B. Lipid synthesis and detoxification

C. Ribosome assembly

D. DNA replication

Answer: B

Question 548

Which of the following correctly describe the Golgi apparatus?

A. It processes and packages proteins for secretion. True or False

B. Proteins move from cis to trans face of the Golgi. True or False

C. Glycosylation of proteins occurs in the Golgi. True or False

D. The Golgi is the site of oxidative phosphorylation. True or False

Answers: A - True, B - True, C - True; D - False (oxidative phosphorylation occurs in mitochondria)

Question 549

Lysosomes contain:

A. Hydrolytic enzymes active at acidic pH (~5)

B. Enzymes for oxidative phosphorylation

C. Enzymes for fatty acid synthesis

D. Ribosomes for protein synthesis

Answer: A

Question 550

I-cell disease (mucolipidosis II) is caused by:

A. Deficiency of a lysosomal enzyme

B. Failure to add mannose-6-phosphate targeting signals to lysosomal enzymes

C. Mutation in the gene encoding cathepsin D

D. Defective peroxisome biogenesis

Answer: B

Question 551

Regarding peroxisomes:

A. Peroxisomes contain catalase that degrades hydrogen peroxide. True or False

B. Very long chain fatty acids (VLCFAs) are oxidized in peroxisomes. True or False

C. Zellweger syndrome results from defective peroxisome biogenesis. True or False

D. Peroxisomes are the primary site of ATP synthesis in the cell. True or False

Answers: A - True, B - True, C - True; D - False (mitochondria are the primary site of ATP synthesis)

Question 552

The cytoskeleton is composed of which of the following?

A. Microfilaments (actin filaments)

B. Intermediate filaments

C. Microtubules

D. All of the above

Answer: D

Question 553

Which of the following correctly describe microtubules?

A. They are composed of tubulin dimers (alpha and beta tubulin). True or False

B. Colchicine inhibits microtubule polymerization. True or False

C. Microtubules are involved in chromosome segregation during mitosis. True or False

D. Microtubules are composed of actin monomers. True or False

Answers: A - True, B - True, C - True; D - False (actin monomers form microfilaments, not microtubules)

Question 554

The cell cycle phase in which DNA synthesis occurs is:

A. G1 phase

B. S phase

C. G2 phase

D. M phase

Answer: B

Question 555

Which of the following are tumor suppressor genes?

A. TP53 (p53). True or False

B. RB1 (retinoblastoma protein). True or False

C. BRCA1 and BRCA2. True or False

D. RAS proto-oncogene. True or False

Answers: A - True, B - True, C - True; D - False (RAS is a proto-oncogene, not a tumor suppressor)

Question 556

Apoptosis (programmed cell death) is characterized by:

A. Cell swelling and membrane rupture

B. Cell shrinkage, chromatin condensation, and apoptotic body formation

C. Inflammatory response

D. Organelle swelling and lysis

Answer: B

Question 557

Which of the following are features of apoptosis?

A. Activation of caspases. True or False

B. DNA laddering on gel electrophoresis. True or False

C. Release of cytochrome c from mitochondria (intrinsic pathway). True or False

D. Apoptosis always causes an inflammatory response. True or False

Answers: A - True, B - True, C - True; D - False (apoptosis is non-inflammatory; necrosis causes inflammation)

Question 558

The proto-oncogene that encodes a GTP-binding protein involved in cell signaling is:

A. TP53

B. RAS

C. RB1

D. PTEN

Answer: B

Question 559

Regarding signal transduction via G-protein coupled receptors (GPCRs):

A. GPCRs have seven transmembrane domains. True or False

B. Gs protein activates adenylyl cyclase to increase cAMP. True or False

C. Gi protein inhibits adenylyl cyclase to decrease cAMP. True or False

D. GPCRs directly phosphorylate intracellular substrates. True or False

Answers: A - True, B - True, C - True; D - False (GPCRs act through second messengers and kinases, not direct phosphorylation)

Question 560

cAMP acts as a second messenger by activating:

A. Protein Kinase C (PKC)

B. Protein Kinase A (PKA)

C. Calmodulin

D. Phospholipase C

Answer: B

Question 561

Which of the following are functions of the nucleus?

A. Storage of genetic information (DNA). True or False

B. Transcription of DNA to RNA. True or False

C. Ribosome subunit assembly in the nucleolus. True or False

D. Translation of mRNA to protein. True or False

Answers: A - True, B - True, C - True; D - False (translation occurs on ribosomes in the cytoplasm)

Question 562

Nuclear pore complexes (NPCs) function to:

A. Allow selective transport of molecules between nucleus and cytoplasm

B. Replicate DNA

C. Transcribe mRNA

D. Package proteins into vesicles

Answer: A

Question 563

Which of the following describes necrosis compared to apoptosis?

A. Necrosis involves cell swelling and membrane rupture. True or False

B. Necrosis triggers an inflammatory response. True or False

C. Necrosis is a regulated, programmed process. True or False

D. Necrosis results from severe cell injury such as ischemia or toxins. True or False

Answers: A - True, B - True, D - True; C - False (necrosis is uncontrolled; apoptosis is programmed)

Question 564

The receptor tyrosine kinase (RTK) pathway is activated by which of the following?

A. Insulin

B. Epidermal growth factor (EGF)

C. Platelet-derived growth factor (PDGF)

D. All of the above

Answer: D

Question 565

Regarding the PI3K/Akt/mTOR signaling pathway:

A. PI3K converts PIP₂ to PIP₃. True or False

B. PTEN is a phosphatase that opposes PI3K by converting PIP₃ back to PIP₂. True or False

C. Akt promotes cell survival and inhibits apoptosis. True or False

D. mTOR activation inhibits protein synthesis. True or False

Answers: A - True, B - True, C - True; D - False (mTOR activation stimulates protein synthesis)

Question 566

Which of the following best describes the unfolded protein response (UPR)?

A. A pathway activated when misfolded proteins accumulate in the ER

B. A pathway for degradation of cytoplasmic proteins

C. A response to mitochondrial stress only

D. A mechanism to increase DNA repair

Answer: A

Question 567

The proteasome degrades proteins that are tagged with:

A. Phosphate groups

B. Ubiquitin chains

C. Acetyl groups

D. Methyl groups

Answer: B

Question 568

Regarding autophagy:

A. Autophagy involves sequestration of cellular components in autophagosomes. True or False

B. Autophagosomes fuse with lysosomes for degradation. True or False

C. Autophagy is induced by nutrient deprivation and mTOR inhibition. True or False

D. Autophagy is a purely pathological process with no normal cellular function. True or False

Answers: A - True, B - True, C - True; D - False (autophagy is a normal homeostatic process)

Question 569

Heat shock proteins (HSPs) function as:

A. Molecular chaperones that assist in protein folding

B. Enzymes of the citric acid cycle

C. Structural components of the nuclear membrane

D. Transport proteins for lipids

Answer: A

Question 570

Which of the following are features of stem cells?

A. Self-renewal capacity. True or False

B. Ability to differentiate into multiple cell types (pluripotency or multipotency). True or False

C. Embryonic stem cells are totipotent. True or False

D. Stem cells cannot be reprogrammed in the laboratory. True or False

Answers: A - True, B - True; C - False (embryonic stem cells are pluripotent; totipotent = fertilized egg/early blastomeres); D - False (iPS cells = reprogrammed stem cells)

Question 571

The Warburg effect in cancer cells refers to:

A. Preferential use of oxidative phosphorylation even in the presence of oxygen

B. Preferential use of aerobic glycolysis (glycolysis even in the presence of oxygen)

C. Increased fatty acid oxidation in cancer cells

D. Decreased glucose uptake in cancer cells

Answer: B

Question 572

Which of the following molecules serves as a second messenger involving calcium signaling?

A. cAMP

B. Inositol trisphosphate (IP₃)

C. cGMP

D. Both B and C are calcium-related second messengers

Answer: B (IP₃ triggers Ca²⁺ release from ER)

Question 573

Regarding gap junctions:

A. Gap junctions allow direct communication between adjacent cells. True or False

B. They are formed by connexin proteins. True or False

C. Gap junctions allow passage of small molecules and ions. True or False

D. Gap junctions require energy (ATP) to transfer molecules between cells. True or False

Answers: A - True, B - True, C - True; D - False (gap junctions are passive channels)

Question 574

Which phase of the cell cycle is the primary checkpoint regulated by p53?

A. G2/M checkpoint

B. G1/S checkpoint

C. Spindle assembly checkpoint

D. S phase checkpoint only

Answer: B

Question 575

Cyclin-dependent kinases (CDKs) require which co-factor for activation?

A. Ubiquitin

B. Cyclin proteins

C. Phosphatase activity

D. ATP alone

Answer: B

Question 576

The extracellular matrix (ECM) is composed of which of the following?

A. Collagen. True or False

B. Fibronectin. True or False

C. Laminin. True or False

D. Glycogen. True or False

Answers: A - True, B - True, C - True; D - False (glycogen is an intracellular energy storage polysaccharide)

Question 577

Integrins are:

A. Nuclear receptors for steroid hormones

B. Cell surface receptors that link ECM to the cytoskeleton

C. Enzymes that degrade the extracellular matrix

D. Transport proteins for lipids

Answer: B

Question 578

Which of the following correctly describe tight junctions (zonula occludens)?

A. They seal adjacent cells to prevent paracellular transport. True or False

B. They are composed of occludin and claudin proteins. True or False

C. They are found at the apical aspect of epithelial cells. True or False

D. Tight junctions allow free movement of membrane proteins between apical and basolateral domains. True or False

Answers: A - True, B - True, C - True; D - False (tight junctions restrict lateral diffusion of membrane proteins)

Question 579

Receptor-mediated endocytosis involves:

A. Clathrin-coated pits

B. Ligand binding to cell surface receptors

C. Formation of endosomes that fuse with lysosomes

D. All of the above

Answer: D

Question 580

Which of the following are correct regarding exocytosis?

A. Exocytosis is the fusion of vesicles with the plasma membrane to release contents outside the cell. True or False

B. It requires SNARE proteins for membrane fusion. True or False

C. Constitutive exocytosis occurs continuously without specific signals. True or False

D. Regulated exocytosis (e.g., neurotransmitter release) requires a triggering signal such as Ca²⁺. True or False

Answers: A - True, B - True, C - True, D - True

Question 581

The enzyme adenylyl cyclase:

A. Converts AMP to cAMP

B. Converts ATP to cAMP + PPi

C. Degrades cAMP to AMP

D. Phosphorylates protein kinase A directly

Answer: B

Question 582

Phosphodiesterase (PDE) terminates second messenger signaling by:

A. Activating adenylyl cyclase

B. Degrading cAMP to AMP or cGMP to GMP

C. Inhibiting protein kinase A

D. Promoting G-protein activation

Answer: B

Question 583

Regarding the JAK-STAT signaling pathway:

A. It is activated by cytokines and growth factors. True or False

B. JAK kinases phosphorylate STAT proteins. True or False

C. Phosphorylated STATs dimerize and translocate to the nucleus to regulate transcription. True or False

D. The JAK-STAT pathway is exclusively found in prokaryotes. True or False

Answers: A - True, B - True, C - True; D - False (it is a eukaryotic signaling pathway)

Question 584

The Wnt signaling pathway regulates:

A. Cell proliferation, differentiation, and embryonic development

B. Exclusively lipid metabolism

C. Only immune cell activation

D. Mitochondrial biogenesis exclusively

Answer: A

Question 585

In the absence of Wnt signaling, beta-catenin is:

A. Stabilized and translocates to the nucleus

B. Phosphorylated by a destruction complex (APC, Axin, GSK-3β) and degraded by proteasome

C. Directly transcribing target genes

D. Activating the MAPK pathway

Answer: B

Question 586

Which of the following are features of the MAP kinase (MAPK/ERK) pathway?

A. It is activated downstream of RAS. True or False

B. The cascade involves sequential activation of Raf, MEK, and ERK. True or False

C. Activated ERK translocates to the nucleus to phosphorylate transcription factors. True or False

D. The MAPK pathway promotes cell death in all contexts. True or False

Answers: A - True, B - True, C - True; D - False (it typically promotes cell survival, proliferation, and differentiation)

Question 587

Which of the following are correct regarding reactive oxygen species (ROS)?

A. ROS include superoxide (O₂⁻), hydrogen peroxide (H₂O₂), and hydroxyl radical (•OH). True or False

B. Superoxide dismutase (SOD) converts superoxide to hydrogen peroxide. True or False

C. Catalase converts hydrogen peroxide to water and oxygen. True or False

D. Excessive ROS production causes oxidative stress and cell damage. True or False

Answers: A - True, B - True, C - True, D - True

Question 588

The enzyme telomerase is active in which of the following?

A. Most somatic cells

B. Cancer cells, germ cells, and stem cells

C. Differentiated neurons only

D. Red blood cells

Answer: B

Question 589

Which of the following correctly describes the endosomal sorting complex required for transport (ESCRT)?

A. It sorts ubiquitinated membrane proteins into multivesicular bodies (MVBs)

B. It is involved in DNA repair

C. It activates the complement cascade

D. It is a component of the ribosome

Answer: A

Question 590

Regarding cellular senescence:

A. Senescent cells are permanently arrested in G1 phase of the cell cycle. True or False

B. Senescence can be induced by telomere shortening. True or False

C. Senescent cells are immediately cleared by apoptosis. True or False

D. Senescence is associated with the senescence-associated secretory phenotype (SASP). True or False

Answers: A - True, B - True, D - True; C - False (senescent cells can persist for extended periods and contribute to aging and inflammation)

Question 591

The primary site of ribosome biogenesis in eukaryotic cells is:

A. The cytoplasm

B. The nucleolus

C. The mitochondria

D. The smooth ER

Answer: B

Question 592

Which of the following are correct regarding the nuclear lamina?

A. It is composed of lamin intermediate filament proteins. True or False

B. It provides structural support to the nucleus. True or False

C. Mutations in lamin A cause progeria (Hutchinson-Gilford syndrome). True or False

D. The nuclear lamina is located on the outer surface of the outer nuclear membrane. True or False

Answers: A - True, B - True, C - True; D - False (it lines the inner surface of the inner nuclear membrane)

Question 593

Clathrin is involved in:

A. Mitochondrial membrane fusion

B. Formation of coated vesicles during endocytosis

C. Ribosome assembly

D. DNA packaging into nucleosomes

Answer: B

Question 594

Which of the following correctly describe SNARE proteins?

A. They mediate membrane fusion between vesicles and target membranes. True or False

B. v-SNAREs are on vesicle membranes; t-SNAREs are on target membranes. True or False

C. Botulinum toxin cleaves SNARE proteins to block neurotransmitter release. True or False

D. SNARE proteins are involved in DNA replication. True or False

Answers: A - True, B - True, C - True; D - False

Question 595

The primary structure of a protein refers to:

A. The three-dimensional folded shape

B. The sequence of amino acids linked by peptide bonds

C. Alpha helices and beta sheets

D. The arrangement of multiple subunits

Answer: B

Question 596

Which of the following types of cell-cell junctions provide mechanical strength to tissues?

A. Tight junctions (zonula occludens)

B. Desmosomes (macula adherens)

C. Gap junctions

D. Adherens junctions only

Answer: B

Question 597

Regarding protein quality control in the ER:

A. Misfolded proteins are retained in the ER by chaperones such as BiP/GRP78. True or False

B. Terminally misfolded proteins are retrotranslocated to the cytoplasm for proteasomal degradation (ERAD). True or False

C. Severe ER stress can trigger apoptosis via the UPR. True or False

D. All proteins are correctly folded in the ER without any quality control. True or False

Answers: A - True, B - True, C - True; D - False

Question 598

The most abundant protein in the human body is:

A. Hemoglobin

B. Albumin

C. Collagen

D. Actin

Answer: C

Question 599

Regarding connexins in cell communication:

A. Connexins form gap junction channels between adjacent cells. True or False

B. Six connexin molecules form one connexon (hemichannel). True or False

C. Gap junctions allow passage of molecules up to ~1000 Da. True or False

D. Connexin mutations cause hereditary deafness (Connexin 26/GJB2). True or False

Answers: A - True, B - True, C - True, D - True

Question 600

Which of the following best summarizes the central dogma of molecular biology?

A. RNA → DNA → Protein

B. DNA → RNA → Protein

C. Protein → RNA → DNA

D. DNA → Protein → RNA

Answer: B

COMPLETE ANSWER KEY: Questions 516-600

Q	Answer	Q	Answer	Q	Answer
516	C	546	A, B, C True; D False	576	A, B, C True; D False
517	A, B, D True; C False	547	B	577	B
518	D	548	A, B, C True; D False	578	A, B, C True; D False
519	A, B, C True; D False	549	A	579	D
520	B	550	B	580	A, B, C, D True
521	A, B, C True; D False	551	A, B, C True; D False	581	B
522	B	552	D	582	B
523	A, B, C, D True	553	A, B, C True; D False	583	A, B, C True; D False
524	B	554	B	584	A
525	A, B, D True; C False	555	A, B, C True; D False	585	B
526	C	556	B	586	A, B, C True; D False
527	C	557	A, B, C True; D False	587	A, B, C, D True
528	A, B, C True; D False	558	B	588	B
529	A	559	A, B, C True; D False	589	A
530	B	560	B	590	A, B, D True; C False
531	A, B, C True; D False	561	A, B, C True; D False	591	B
532	B	562	A	592	A, B, C True; D False
533	B	563	A, B, D True; C False	593	B
534	A, B, C True; D False	564	D	594	A, B, C True; D False
535	B	565	A, B, C True; D False	595	B
536	A, B, C True; D False	566	A	596	B
537	C	567	B	597	A, B, C True; D False
538	A, B, C True; D False	568	A, B, C True; D False	598	C
539	C	569	A	599	A, B, C, D True
540	A, B, D True; C False	570	A, B True; C, D False	600	B
541	B	571	B
542	A, B, C True; D False	572	B
543	B	573	A, B, C True; D False
544	A, B, C True; D False	574	B
545	A	575	B

All 600 Biochemistry MCQs are now complete, drawn from Vasudevan's Textbook of Biochemistry for Medical Students, Harper's Illustrated Biochemistry (32nd Ed.), Lippincott's Illustrated Reviews: Biochemistry, and Basic Medical Biochemistry (6th Ed.), covering:

Topic 1 - Fluid & Electrolytes: Qs 1-50
Topic 2 - Amino Acid Chemistry: Qs 51-100
Topic 3 - Carbohydrate Chemistry: Qs 101-150
Topic 4 - Lipid Chemistry: Qs 151-200
Topic 5 - Nucleic Acid Chemistry: Qs 201-250
Topic 6 - Immunology: Qs 251-300
Topic 7 - Muscle Biochemistry & Metabolism: Qs 301-350
Topic 8 - Protein & Amino Acid Metabolism: Qs 351-400
Topic 9 - Carbohydrate Metabolism: Qs 401-450
Topic 10 - Lipid Metabolism: Qs 451-500
Topic 11 - Nucleic Acid Metabolism: Qs 501-540
Topic 12 - Cell Biochemistry: Qs 541-600

Create a PDF document containing all 600 Biochemistry MCQs

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