Respiration Practice Questions
IGCSE (Cambridge) · IGCSE Biology · 143 free MCQs with instant results and detailed explanations.
143
Total
44
Easy
69
Medium
30
Hard
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Sample Questions from Respiration
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
What is the primary purpose of respiration in living organisms?
A.
To produce energy
B.
To consume oxygen
C.
To remove waste
D.
To maintain temperature
Show Answer & Explanation
Correct Answer: A
The primary purpose of respiration is to produce energy for cellular activities through the breakdown of glucose with the help of oxygen.
Q2
Easy
Which of the following organisms primarily uses anaerobic respiration?
A.
Humans
B.
Yeast
C.
Dogs
D.
Cats
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Correct Answer: B
Yeast primarily uses anaerobic respiration to convert sugars into alcohol and carbon dioxide in the absence of oxygen, a process known as fermentation.
Q3
Easy
During which process is glucose broken down to release energy in the presence of oxygen?
A.
Fermentation
B.
Photosynthesis
C.
Aerobic respiration
D.
Glycolysis
Show Answer & Explanation
Correct Answer: C
Aerobic respiration is the process in which glucose is broken down in the presence of oxygen to release energy, carbon dioxide, and water.
Q4
Medium
In anaerobic respiration, which product is commonly produced in yeast?
A.
Lactic acid
B.
Ethanol
C.
Oxygen
D.
Carbon dioxide
Show Answer & Explanation
Correct Answer: B
In yeast, anaerobic respiration leads to the production of ethanol and carbon dioxide. Ethanol is the primary alcohol produced, making option B the correct answer.
Q5
Medium
What is the role of oxygen in aerobic respiration?
A.
It is a substrate for glycolysis.
B.
It acts as a final electron acceptor.
C.
It initiates the Krebs cycle.
D.
It is produced during respiration.
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Correct Answer: B
Oxygen serves as the final electron acceptor in aerobic respiration, allowing the electron transport chain to function efficiently and leading to the formation of water.
Q6
Medium
Which of the following statements best describes anaerobic respiration in human muscle cells?
A.
It requires oxygen to function.
B.
It produces lactate when oxygen is scarce.
C.
It only occurs during rest.
D.
It leads to higher ATP yield than aerobic respiration.
Show Answer & Explanation
Correct Answer: B
Anaerobic respiration in human muscle cells occurs when oxygen is limited, resulting in the production of lactate (lactic acid) as a byproduct.
Q7
Medium
If a cell produces 36 ATP molecules during aerobic respiration, how many molecules of glucose were likely used?
A.
1
B.
2
C.
3
D.
4
Show Answer & Explanation
Correct Answer: A
Typically, one molecule of glucose produces about 30 to 38 ATP molecules during aerobic respiration. Therefore, if 36 ATP are produced, it is likely that only one glucose molecule was used.
Q8
Hard
During anaerobic respiration in human muscles, which of the following products is primarily responsible for muscle fatigue?
A.
Lactic Acid
B.
Glucose
C.
Carbon Dioxide
D.
Oxygen
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Correct Answer: A
Lactic acid accumulates in muscles during anaerobic respiration due to insufficient oxygen, leading to muscle fatigue.
Q9
Hard
A student measures the rate of respiration in yeast using a glucose solution. If the concentration of glucose is doubled, what effect is likely to occur on the rate of respiration, assuming temperature and other conditions remain constant?
A.
Rate of respiration decreases
B.
Rate of respiration remains the same
C.
Rate of respiration increases
D.
Rate of respiration fluctuates unpredictably
Show Answer & Explanation
Correct Answer: C
Increasing the concentration of glucose provides more substrate for fermentation, which typically increases the rate of respiration in yeast.
Q10
Hard
In anaerobic respiration, which of the following products is most commonly produced in yeast?
A.
Ethanol
B.
Lactic acid
C.
Carbon dioxide
D.
Glucose
Show Answer & Explanation
Correct Answer: A
Ethanol is the primary product of anaerobic respiration in yeast, a process known as fermentation. While lactic acid is produced in muscle cells during anaerobic respiration, it is not the main product in yeast.
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Respiration — IGCSE (Cambridge) IGCSE Biology Practice Questions Online
This page contains 143 practice MCQs for the chapter Respiration in IGCSE (Cambridge) IGCSE Biology. The questions are organized by difficulty — 44 easy, 69 medium, 30 hard — so you can choose the right level for your preparation.
Every question includes a detailed explanation to help you understand the concept, not just memorize answers. Take a timed quiz to simulate exam conditions, or practice at your own pace with no time limit.