Creatinine phosphate MCQs With Answer

Creatinine phosphate MCQs With Answer is an essential topic for B. Pharm students studying biochemical energetics and clinical diagnostics. This introduction clarifies that the correct term is creatine phosphate (phosphocreatine), a high-energy reserve that rapidly regenerates ATP in muscle and brain via the creatine kinase system. Understanding its synthesis, transport, creatine kinase isoenzymes, clinical significance (e.g., rhabdomyolysis, myocardial injury), laboratory assays, and factors affecting levels is vital for pharmacology, therapeutics, and lab medicine. These focused MCQs emphasize mechanisms, lab interpretation, drug interactions (e.g., statins), and sample handling to strengthen exam readiness and practical application. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which molecule is the immediate high-energy phosphate reserve used to regenerate ATP in muscle?

• Glucose-6-phosphate
• Creatine phosphate (phosphocreatine)
• Adenosine diphosphate
• Glycogen

Correct Answer: Creatine phosphate (phosphocreatine)

Q2. Which enzyme catalyzes the reversible transfer of a phosphate group between ATP and creatine?

• Hexokinase
• Creatine kinase
• Adenylate kinase
• Lactate dehydrogenase

Correct Answer: Creatine kinase

Q3. Where are the main organs of endogenous creatine synthesis located?

• Pancreas and spleen
• Kidney and liver
• Muscle and heart
• Brain and adrenal gland

Correct Answer: Kidney and liver

Q4. Which substrate pair is used by creatine kinase to form creatine phosphate?

• Creatine and ATP
• Creatinine and ADP
• Creatine and glucose-6-phosphate
• Phosphoenolpyruvate and ADP

Correct Answer: Creatine and ATP

Q5. Which term is a common misnomer often used in place of phosphocreatine?

• Creatinine phosphate
• Phosphoenolpyruvate
• Creatine kinase
• Creatine monohydrate

Correct Answer: Creatinine phosphate

Q6. Which creatine kinase isoform predominates in skeletal muscle?

• CK-MB
• CK-BB
• CK-MM
• CK-MT

Correct Answer: CK-MM

Q7. Which creatine kinase isoform is most useful clinically as a marker of myocardial injury (historically)?

• CK-MB
• CK-MM
• CK-BB
• CK-CK

Correct Answer: CK-MB

Q8. Which clinical condition is most likely to produce markedly elevated serum creatine kinase activity?

• Hypothyroidism without myopathy
• Rhabdomyolysis
• Mild dehydration
• Viral upper respiratory infection

Correct Answer: Rhabdomyolysis

Q9. Creatine is transported into muscle cells primarily by which mechanism?

• Facilitated diffusion through aquaporins
• Sodium-dependent creatine transporter
• Passive diffusion across lipid bilayer
• Endocytosis

Correct Answer: Sodium-dependent creatine transporter

Q10. Which laboratory factor can artificially increase measured serum CK levels?

• Strenuous exercise prior to blood draw
• Fasting for 12 hours
• Drinking water before phlebotomy
• Using EDTA instead of serum tubes

Correct Answer: Strenuous exercise prior to blood draw

Q11. The creatine kinase reaction is reversible. Which direction predominates during high-energy demand (e.g., muscle contraction)?

• Conversion of creatine phosphate to creatine and ADP to ATP
• Conversion of creatine to creatine phosphate and ATP to ADP
• Formation of creatinine from creatine phosphate
• Oxidation of creatine to creatinine phosphate

Correct Answer: Conversion of creatine phosphate to creatine and ADP to ATP

Q12. Which compound is the non-enzymatic breakdown product excreted in urine and commonly measured as a renal function marker?

• Creatine phosphate
• Creatinine
• Guanidinoacetate
• Phosphocreatine

Correct Answer: Creatinine

Q13. Which step is the rate-limiting enzyme in endogenous creatine biosynthesis?

• Guanidinoacetate N-methyltransferase (GAMT)
• Arginine:glycine amidinotransferase (AGAT)
• Creatine kinase
• Creatine transporter activity

Correct Answer: Arginine:glycine amidinotransferase (AGAT)

Q14. Which nutritional supplement increases muscle creatine and phosphocreatine stores when used appropriately?

• Creatine monohydrate
• Glucosamine
• Vitamin C
• L-tryptophan

Correct Answer: Creatine monohydrate

Q15. In which cellular compartment is phosphocreatine mainly located in muscle fibers?

• Nucleus
• Sarcoplasm/cytosol and near mitochondria
• Lysosomes
• Golgi apparatus

Correct Answer: Sarcoplasm/cytosol and near mitochondria

Q16. The phosphocreatine shuttle primarily facilitates which process?

• Transport of long-chain fatty acids into mitochondria
• Rapid transfer of high-energy phosphate from mitochondria to cytosol
• Storage of glycogen in muscle
• Excretion of creatinine by the kidney

Correct Answer: Rapid transfer of high-energy phosphate from mitochondria to cytosol

Q17. Which factor decreases tissue phosphocreatine levels?

• Rest and recovery
• Acute high-intensity exercise
• Oral creatine supplementation
• ATP repletion

Correct Answer: Acute high-intensity exercise

Q18. Creatinine differs from creatine and phosphocreatine because creatinine is:

• An enzyme
• A stable, non-enzymatic breakdown product excreted by kidneys
• A phosphorylated high-energy molecule
• A transporter protein

Correct Answer: A stable, non-enzymatic breakdown product excreted by kidneys

Q19. Which clinical drug class is commonly associated with increased risk of myopathy and raised CK levels?

• Beta blockers
• Statins (HMG-CoA reductase inhibitors)
• Proton pump inhibitors
• ACE inhibitors

Correct Answer: Statins (HMG-CoA reductase inhibitors)

Q20. A B. Pharm student should know that phosphocreatine is synthesized from creatine by phosphorylation using which phosphate donor?

• Inorganic phosphate (Pi)
• ATP
• ADP
• GTP

Correct Answer: ATP

Q21. Which imaging or spectroscopy technique can non-invasively measure phosphocreatine concentrations in tissues?

• 19F MRI
• 31P Magnetic Resonance Spectroscopy (31P-MRS)
• CT scan
• Positron emission tomography (PET)

Correct Answer: 31P Magnetic Resonance Spectroscopy (31P-MRS)

Q22. In the context of pharmacology, why is understanding phosphocreatine metabolism important?

• It directly metabolizes most drugs
• It influences cellular energy buffering and drug-induced myopathies
• It determines drug absorption in the intestine
• It is the primary pathway for drug excretion

Correct Answer: It influences cellular energy buffering and drug-induced myopathies

Q23. Which laboratory assay is commonly used to measure creatine kinase activity indirectly?

• Enzymatic spectrophotometric assay coupling creatine kinase to NAD(P)H formation
• Immunofluorescence staining of muscle biopsy only
• Urine dipstick
• Direct measurement of phosphocreatine by colorimetry

Correct Answer: Enzymatic spectrophotometric assay coupling creatine kinase to NAD(P)H formation

Q24. Which statement about creatine supplementation safety is most accurate for healthcare students?

• High-dose creatine always causes renal failure
• Standard doses are generally safe in healthy individuals but require monitoring in renal disease
• Creatine is completely ineffective for all athletes
• Creatine must be given intravenously to be effective

Correct Answer: Standard doses are generally safe in healthy individuals but require monitoring in renal disease

Q25. Which metabolite accumulates when creatine is nonenzymatically converted and excreted, used to assess kidney function?

• Guanidinoacetate
• Creatinine
• Uric acid
• Ammonia

Correct Answer: Creatinine

Q26. A rise in serum CK-MB relative to total CK is most suggestive of which event?

• Hepatic injury
• Cardiac muscle damage
• CNS ischemia
• Renal tubular necrosis

Correct Answer: Cardiac muscle damage

Q27. The phosphocreatine system provides energy for muscle contraction primarily during which time frame?

• Long endurance events beyond 30 minutes
• Immediate short bursts up to ~10 seconds
• Chronic low-intensity activity
• Only during sleep

Correct Answer: Immediate short bursts up to ~10 seconds

Q28. Which cofactor is typically required for creatine kinase activity in vitro assays?

• Calcium ions
• Magnesium ions (Mg2+)
• Vitamin B12
• Iron (Fe2+)

Correct Answer: Magnesium ions (Mg2+)

Q29. Which of the following reduces the accuracy of serum CK interpretation in diagnosing myocardial infarction today?

• CK-MB is completely specific for skeletal muscle
• Troponin assays are more specific and sensitive for myocardial injury
• CK assays are cheaper and therefore better
• CK cannot be measured in modern labs

Correct Answer: Troponin assays are more specific and sensitive for myocardial injury

Q30. Which genetic disorder directly affects creatine synthesis leading to neurological symptoms?

• GAMT deficiency (guanidinoacetate methyltransferase deficiency)
• Cystic fibrosis
• Hemochromatosis
• Phenylketonuria

Correct Answer: GAMT deficiency (guanidinoacetate methyltransferase deficiency)

Q31. In skeletal muscle, creatine kinase located near mitochondria is primarily responsible for:

• Degrading ATP to AMP
• Phosphorylating creatine to form phosphocreatine for export of energy
• Transporting creatinine into mitochondria
• Producing lactic acid

Correct Answer: Phosphorylating creatine to form phosphocreatine for export of energy

Q32. Which dietary precursor is required for endogenous creatine synthesis?

• Tyrosine
• Glycine and arginine
• Leucine
• Choline

Correct Answer: Glycine and arginine

Q33. Which clinical sample is most appropriate for routine measurement of serum CK activity?

• Urine sample
• Serum collected in plain tube after avoiding recent exercise
• Whole blood in heparinized tube without centrifugation
• Saliva

Correct Answer: Serum collected in plain tube after avoiding recent exercise

Q34. Which condition is least likely to elevate serum creatine kinase?

• Intramuscular injection
• Mild viral pharyngitis without myositis
• Severe crush injury
• Statin-induced myopathy

Correct Answer: Mild viral pharyngitis without myositis

Q35. Which molecule accepts phosphate from ATP to generate phosphocreatine in the creatine kinase reaction?

• Creatinine
• Creatine
• Guanidinoacetate
• Phosphoenolpyruvate

Correct Answer: Creatine

Q36. Which pharmacological principle relates to creatine supplement interactions?

• Creatine has strong cytochrome P450 inhibition
• Concomitant nephrotoxic drugs may increase renal risk with creatine use
• Creatine acts as a diuretic and reduces drug concentrations
• Creatine universally increases absorption of oral drugs

Correct Answer: Concomitant nephrotoxic drugs may increase renal risk with creatine use

Q37. Phosphocreatine levels are most directly involved in which cellular process?

• Protein synthesis
• Immediate ATP buffering and energy transfer
• DNA replication fidelity
• Membrane lipid synthesis

Correct Answer: Immediate ATP buffering and energy transfer

Q38. Which lab artifact can falsely lower measured CK activity?

• Delayed separation of serum from clot and prolonged storage at room temperature
• Collecting blood immediately after exercise
• Using lithium heparin tubes for CK measurement
• Transporting sample at 4°C promptly

Correct Answer: Delayed separation of serum from clot and prolonged storage at room temperature

Q39. Which of the following best describes the fate of phosphocreatine during repeated high-intensity exercise?

• Phosphocreatine stores are rapidly depleted and require minutes for resynthesis
• Phosphocreatine stores increase immediately during exercise
• Phosphocreatine is converted directly into glycogen
• Phosphocreatine is excreted in urine

Correct Answer: Phosphocreatine stores are rapidly depleted and require minutes for resynthesis

Q40. Which laboratory marker has largely replaced CK-MB for early and specific detection of myocardial injury?

• Troponin I/T
• ALT (alanine transaminase)
• Alkaline phosphatase
• CRP (C-reactive protein)

Correct Answer: Troponin I/T

Q41. In skeletal muscle, what role does cytosolic creatine kinase (CK-MM) play at the myofibrils?

• Converting lactic acid to pyruvate
• Regenerating ATP locally at sites of ATP consumption
• Transporting oxygen
• Breaking down glycogen

Correct Answer: Regenerating ATP locally at sites of ATP consumption

Q42. Which statement about phosphocreatine measurement in routine clinical labs is true?

• Phosphocreatine is routinely measured in serum panels
• Phosphocreatine is usually assessed noninvasively by 31P-MRS rather than routine blood tests
• Phosphocreatine can be measured by urine dipstick
• Most clinical labs report phosphocreatine daily

Correct Answer: Phosphocreatine is usually assessed noninvasively by 31P-MRS rather than routine blood tests

Q43. Which metabolite must be methylated by GAMT to form creatine during biosynthesis?

• Arginine
• Guanidinoacetate
• Creatinine
• Ornithine

Correct Answer: Guanidinoacetate

Q44. Which population should use creatine supplements with caution and under medical advice?

• Healthy young adults with no comorbidities
• Individuals with pre-existing renal impairment
• Athletes during off-season only
• People allergic to lactose

Correct Answer: Individuals with pre-existing renal impairment

Q45. A B. Pharm student learning lab interpretation should note that persistently high CK with muscle weakness suggests:

• Acute viral infection only
• Chronic myopathy or muscular dystrophy that requires further evaluation
• Low dietary protein intake
• Dehydration exclusively

Correct Answer: Chronic myopathy or muscular dystrophy that requires further evaluation

Q46. Which biochemical property enables phosphocreatine to act as an energy buffer?

• Very high standard free energy of hydrolysis of its phosphate bond
• Ability to bind oxygen tightly
• Being highly water-insoluble
• Direct participation in oxidative phosphorylation

Correct Answer: Very high standard free energy of hydrolysis of its phosphate bond

Q47. In pharmacokinetics teaching, why might creatine kinase elevations confound adverse event assessment?

• CK increases are unrelated to muscle injury
• Drug-induced myopathies can raise CK, so causality assessment requires clinical correlation
• CK values always indicate heart failure
• CK is only influenced by diet and not drugs

Correct Answer: Drug-induced myopathies can raise CK, so causality assessment requires clinical correlation

Q48. Which therapeutic approach has been studied for creatine deficiency syndromes?

• High-dose statin therapy
• Oral creatine supplementation and dietary management
• Chelation therapy
• Long-term corticosteroids only

Correct Answer: Oral creatine supplementation and dietary management

Q49. Which analytical precaution is important when sending a patient sample for CK assay?

• Allow patient to exercise vigorously before sampling
• Avoid hemolysis and collect sample after rest to prevent false elevations
• Use urine instead of serum for CK measurement
• Freeze the sample repeatedly before assay

Correct Answer: Avoid hemolysis and collect sample after rest to prevent false elevations

Q50. For exam preparation, which conceptual distinction is most important between creatine, creatine phosphate, and creatinine?

• Creatine is an enzyme, creatine phosphate is a vitamin, creatinine is a neurotransmitter
• Creatine is a substrate synthesized in body, creatine phosphate (phosphocreatine) stores high-energy phosphate, creatinine is the metabolic waste product excreted by kidneys
• All three are identical molecules with different names
• Creatinine stores energy, creatine is excreted, creatine phosphate is a hormone

Correct Answer: Creatine is a substrate synthesized in body, creatine phosphate (phosphocreatine) stores high-energy phosphate, creatinine is the metabolic waste product excreted by kidneys

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com