1. What is the main function of buffers in the body?
A) Increase acidity
B) Maintain pH stability
C) Increase alkalinity
D) Break down toxins
Answer: B) Maintain pH stability
2. Which of the following is a common buffer in human blood?
A) Carbonic acid-bicarbonate buffer
B) Acetic acid
C) Sodium chloride
D) Nitric acid
Answer: A) Carbonic acid-bicarbonate buffer
3. What is the normal pH range of human blood?
A) 5.5–6.5
B) 7.2–7.6
C) 7.35–7.45
D) 8.0–8.5
Answer: C) 7.35–7.45
4. What happens when the pH of blood decreases below 7.35?
A) Respiratory acidosis
B) Alkalosis
C) Respiratory alkalosis
D) Respiratory homeostasis
Answer: A) Respiratory acidosis
5. Which of the following substances acts as a buffer by neutralizing acids?
A) Sodium hydroxide
B) Potassium bicarbonate
C) Ammonia
D) Hydrochloric acid
Answer: B) Potassium bicarbonate
6. Buffers primarily affect the concentration of which of the following in solutions?
A) Glucose
B) Hydrogen ions
C) Oxygen molecules
D) Carbon dioxide
Answer: B) Hydrogen ions
7. What is the pH of a neutral solution?
A) 7
B) 5
C) 9
D) 0
Answer: A) 7
8. What do buffers do when the pH of a solution becomes too acidic?
A) They release hydrogen ions
B) They absorb hydrogen ions
C) They increase the concentration of hydroxide ions
D) They release carbon dioxide
Answer: B) They absorb hydrogen ions
9. Which of the following buffers is found in the intracellular fluid of cells?
A) Phosphate buffer system
B) Carbonic acid-bicarbonate buffer
C) Protein buffer system
D) Both A and C
Answer: D) Both A and C
10. The bicarbonate buffer system in the blood regulates pH by balancing which two compounds?
A) Sodium chloride and potassium
B) Carbon dioxide and bicarbonate
C) Glucose and oxygen
D) Nitrogen and ammonia
Answer: B) Carbon dioxide and bicarbonate
11. What type of solution has a pH greater than 7?
A) Acidic
B) Neutral
C) Basic or alkaline
D) Hypertonic
Answer: C) Basic or alkaline
12. Which enzyme helps regulate the bicarbonate buffer system by converting CO₂ into carbonic acid?
A) Catalase
B) Carbonic anhydrase
C) Lactase
D) Amylase
Answer: B) Carbonic anhydrase
13. Which of the following could occur if the pH of body fluids deviates too far from normal?
A) Enzyme denaturation
B) Disruption of protein functions
C) Disruption of cellular metabolism
D) All of the above
Answer: D) All of the above
14. What does the term ‘buffer capacity’ refer to?
A) The ability of a buffer to maintain the pH
B) The pH value at which a buffer becomes ineffective
C) The range of pH values in which a buffer is effective
D) The amount of water a buffer can hold
Answer: C) The range of pH values in which a buffer is effective
15. Which of the following systems is used by the body to regulate pH levels in blood and tissues?
A) Digestive system
B) Respiratory system
C) Endocrine system
D) Excretory system
Answer: B) Respiratory system
16. Which is an example of an acidic buffer?
A) Sodium bicarbonate
B) Phosphate buffer
C) Acetic acid
D) Sodium acetate
Answer: C) Acetic acid
17. What happens when there is an excess of bicarbonate in the body?
A) Alkalosis
B) Acidosis
C) Respiratory acidosis
D) Respiratory alkalosis
Answer: A) Alkalosis
18. What is the relationship between pH and hydrogen ion concentration?
A) Direct
B) Indirect
C) No relationship
D) Proportional
Answer: B) Indirect
19. Which is NOT a function of buffers in biological systems?
A) Stabilizing pH
B) Enhancing enzyme activity
C) Neutralizing excess acid or base
D) Maintaining homeostasis
Answer: B) Enhancing enzyme activity
20. Which compound can increase the pH of a solution, making it more basic?
A) Acetic acid
B) Hydrochloric acid
C) Sodium hydroxide
D) Phosphoric acid
Answer: C) Sodium hydroxide
21. How does the body respond to acidosis (a drop in pH)?
A) By increasing breathing rate
B) By decreasing kidney filtration
C) By secreting more CO₂
D) By decreasing bicarbonate production
Answer: A) By increasing breathing rate
22. Which of the following best describes the pH scale?
A) A logarithmic scale measuring hydrogen ion concentration
B) A linear scale measuring alkalinity
C) A linear scale measuring acidity
D) A scale measuring oxygen concentration
Answer: A) A logarithmic scale measuring hydrogen ion concentration
23. What role do kidneys play in regulating pH?
A) They excrete excess hydrogen ions
B) They absorb excess bicarbonate
C) They regulate fluid levels
D) They produce glucose
Answer: A) They excrete excess hydrogen ions
24. What does the pH of a solution indicate?
A) The concentration of hydrogen ions
B) The temperature of the solution
C) The volume of the solution
D) The concentration of oxygen
Answer: A) The concentration of hydrogen ions
25. How does the phosphate buffer system function?
A) It uses phosphate ions to neutralize hydrogen ions
B) It uses carbonic acid to neutralize hydroxide ions
C) It produces proteins to maintain pH
D) It releases oxygen to adjust pH
Answer: A) It uses phosphate ions to neutralize hydrogen ions
26. Which of the following would be a likely consequence of prolonged acidosis in the body?
A) Hypoglycemia
B) Enzyme malfunction
C) Excessive protein synthesis
D) Increased bone density
Answer: B) Enzyme malfunction
27. What is the pH of a solution with a hydrogen ion concentration of 10⁻⁸ M?
A) 8
B) 7
C) 6
D) 9
Answer: A) 8
28. What is an example of a base used in buffers?
A) HCl
B) NaOH
C) H₂CO₃
D) CH₃COOH
Answer: B) NaOH
29. Which component of the body is the most sensitive to changes in pH?
A) Liver
B) Brain
C) Skin
D) Muscles
Answer: B) Brain
30. What does a pH of 4 indicate about the solution?
A) Strongly alkaline
B) Neutral
C) Weakly acidic
D) Strongly acidic
Answer: D) Strongly acidic
