Respiration Practice Questions
WAEC (West Africa) · WAEC Biology · 145 free MCQs with instant results and detailed explanations.
145
Total
44
Easy
71
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 absorb nutrients
C.
To excrete waste
D.
To grow taller
Show Answer & Explanation
Correct Answer: A
The primary purpose of respiration is to produce energy in the form of ATP, which is essential for all cellular processes.
Q2
Easy
Which of the following is a byproduct of aerobic respiration?
A.
Lactic acid
B.
Carbon dioxide
C.
Ethanol
D.
Glucose
Show Answer & Explanation
Correct Answer: B
Carbon dioxide is a byproduct of aerobic respiration, where glucose is metabolized with oxygen, releasing CO2 and water.
Q3
Easy
Which of the following processes occurs in the mitochondria of eukaryotic cells?
A.
Photosynthesis
B.
Cellular Respiration
C.
Fermentation
D.
Transcription
Show Answer & Explanation
Correct Answer: B
Cellular respiration takes place in the mitochondria, where glucose is converted into ATP using oxygen. This is essential for energy production in eukaryotic cells.
Q4
Medium
Which of the following processes is NOT a part of aerobic respiration?
A.
Krebs cycle
B.
Electron transport chain
C.
Glycolysis
D.
Fermentation
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Correct Answer: D
Fermentation is an anaerobic process that occurs in the absence of oxygen, while Krebs cycle, electron transport chain, and glycolysis are all parts of aerobic respiration.
Q5
Medium
During which stage of cellular respiration is the majority of ATP produced?
A.
Glycolysis
B.
Krebs cycle
C.
Electron transport chain
D.
Lactic acid fermentation
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Correct Answer: C
The majority of ATP is produced during the electron transport chain, where oxidative phosphorylation occurs, leading to the generation of a large amount of ATP.
Q6
Medium
What is the primary purpose of the Krebs cycle in cellular respiration?
A.
Production of glucose
B.
Generation of carbon dioxide
C.
Oxidation of acetyl-CoA
D.
Formation of lactic acid
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Correct Answer: C
The primary purpose of the Krebs cycle is to oxidize acetyl-CoA to produce electron carriers (NADH and FADH2) for the electron transport chain.
Q7
Medium
In anaerobic respiration, which of the following is a product of glucose breakdown in yeast?
A.
Lactic acid
B.
Ethanol
C.
Oxygen
D.
Carbon dioxide
Show Answer & Explanation
Correct Answer: B
In anaerobic respiration, yeast converts glucose to ethanol and carbon dioxide during fermentation, with ethanol being the main product.
Q8
Hard
Which of the following statements correctly describes the role of oxygen in aerobic respiration?
A.
Oxygen is required to convert glucose into pyruvate.
B.
Oxygen is used to synthesize ATP directly from glucose.
C.
Oxygen acts as the final electron acceptor in the electron transport chain.
D.
Oxygen is not essential for energy production in aerobic conditions.
Show Answer & Explanation
Correct Answer: C
Oxygen serves as the final electron acceptor in the electron transport chain, allowing for the production of ATP through oxidative phosphorylation, making it crucial for aerobic respiration.
Q9
Hard
If a yeast culture is placed in an anaerobic environment, which of the following products is primarily formed during respiration?
A.
Carbon dioxide and water
B.
Lactic acid and ATP
C.
Ethanol and carbon dioxide
D.
Glucose and oxygen
Show Answer & Explanation
Correct Answer: C
In anaerobic conditions, yeast performs fermentation, producing ethanol and carbon dioxide from glucose, which is a hallmark of anaerobic metabolic processes in yeast.
Q10
Hard
During aerobic respiration, which of the following processes occurs in the mitochondria?
A.
Glycolysis
B.
Electron transport chain
C.
Fermentation
D.
Krebs cycle
Show Answer & Explanation
Correct Answer: B
The electron transport chain, which is a crucial part of aerobic respiration, occurs in the inner mitochondrial membrane, making option B the correct choice. Glycolysis occurs in the cytoplasm, fermentation is anaerobic, and the Krebs cycle occurs in the mitochondrial matrix.
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Respiration — WAEC (West Africa) WAEC Biology Practice Questions Online
This page contains 145 practice MCQs for the chapter Respiration in WAEC (West Africa) WAEC Biology. The questions are organized by difficulty — 44 easy, 71 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.