Respiration Practice Questions
NECO (Nigeria) · NECO Biology · 145 free MCQs with instant results and detailed explanations.
145
Total
38
Easy
77
Medium
30
Hard
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Sample Questions from Respiration
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Q1
Easy
What is the primary purpose of respiration in living organisms?
A.
To produce energy
B.
To grow
C.
To reproduce
D.
To excrete waste
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Correct Answer: A
The primary purpose of respiration is to convert glucose and oxygen into energy (ATP), which is essential for various cellular functions.
Q2
Easy
Which gas is primarily taken in by plants during photosynthesis and released during respiration?
A.
Carbon dioxide
B.
Oxygen
C.
Nitrogen
D.
Hydrogen
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Correct Answer: A
Plants absorb carbon dioxide for photosynthesis, and during respiration, they release carbon dioxide back into the environment as a by-product.
Q3
Easy
In anaerobic respiration, what is the end product of glucose breakdown in yeast?
A.
Ethanol and carbon dioxide
B.
Lactic acid
C.
Glucose
D.
Oxygen
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Correct Answer: A
In anaerobic respiration, yeast converts glucose into ethanol and carbon dioxide, which is important in fermentation processes.
Q4
Medium
Which of the following statements best describes aerobic respiration?
A.
It occurs in the absence of oxygen and produces less energy.
B.
It occurs in the presence of oxygen and produces a high amount of energy.
C.
It produces alcohol and carbon dioxide as end products.
D.
It only occurs in plants.
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Correct Answer: B
Aerobic respiration occurs in the presence of oxygen and typically produces a large amount of energy (ATP) compared to anaerobic processes. It results in carbon dioxide and water as byproducts.
Q5
Medium
In which part of the cell does aerobic respiration predominantly occur?
A.
Cytoplasm
B.
Mitochondria
C.
Nucleus
D.
Ribosome
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Correct Answer: B
Aerobic respiration predominantly takes place in the mitochondria, where the Krebs cycle and electron transport chain occur, resulting in the production of ATP.
Q6
Medium
Which of the following is a byproduct of anaerobic respiration in yeast?
A.
Oxygen
B.
Lactic acid
C.
Ethanol
D.
Glucose
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Correct Answer: C
In yeast, anaerobic respiration leads to the production of ethanol and carbon dioxide. Ethanol is the principal byproduct of alcoholic fermentation.
Q7
Medium
How many molecules of ATP are typically produced from one molecule of glucose during aerobic respiration?
A.
2
B.
18
C.
32
D.
36
Show Answer & Explanation
Correct Answer: C
Typically, aerobic respiration yields approximately 32 molecules of ATP from one molecule of glucose when considering the complete oxidation of glucose through glycolysis, the Krebs cycle, and oxidative phosphorylation.
Q8
Hard
During aerobic respiration, glucose is metabolized in a series of reactions. What is the primary purpose of the Krebs cycle in this process?
A.
To produce ATP through substrate-level phosphorylation
B.
To generate electron carriers for the electron transport chain
C.
To convert glucose into pyruvate
D.
To produce carbon dioxide and water as waste products
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Correct Answer: B
The primary purpose of the Krebs cycle is to generate electron carriers (NADH and FADH2) that are crucial for the electron transport chain, where ATP is produced via oxidative phosphorylation. While ATP is produced in smaller amounts directly, the main output is the electron carriers used later.
Q9
Hard
Which of the following statements best describes anaerobic respiration?
A.
It occurs in the presence of oxygen and produces more energy than aerobic respiration.
B.
It occurs without oxygen and produces less energy compared to aerobic respiration.
C.
It involves the breakdown of glucose into carbon dioxide and water.
D.
It is the process of energy production primarily in plants.
Show Answer & Explanation
Correct Answer: B
Anaerobic respiration occurs in the absence of oxygen and results in the production of less energy compared to aerobic respiration, typically yielding only 2 ATP molecules per glucose molecule.
Q10
Hard
During cellular respiration, which of the following is NOT a product of the Krebs cycle?
A.
NADH
B.
FADH2
C.
ATP
D.
Pyruvate
Show Answer & Explanation
Correct Answer: D
Pyruvate is produced during glycolysis, prior to entering the Krebs cycle, while NADH, FADH2, and ATP are products of the Krebs cycle itself.
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Respiration — NECO (Nigeria) NECO Biology Practice Questions Online
This page contains 145 practice MCQs for the chapter Respiration in NECO (Nigeria) NECO Biology. The questions are organized by difficulty — 38 easy, 77 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.