Cellular Respiration — Drills · Grade 10 Science

Chapter: Matter & Energy in Living Systems

What these drills covers

By the end of Cellular Respiration you should be able to:

8 questions, written answer, numeric and multiple choice, each with a worked explanation.

Vocabulary used: glycolysis, citric acid cycle, oxidative phosphorylation, fermentation, aerobic respiration.

Problem 1

Does the respiratory electron-transport chain produce CO₂? Explain.
Answer and explanation

No. It transfers electrons to oxygen and supports water formation; CO₂ is released earlier during carbon-processing reactions.

Problem 2

At a stated model yield of 30 ATP per glucose, how many ATP result from 3 glucose?
Answer and explanation

90 ATP

3 × 30 = 90 in this model.

Problem 3

Glycolysis takes place in the
  1. mitochondrion's inner membrane
  2. cytoplasm
  3. nucleus
  4. chloroplast
Answer and explanation

cytoplasm

Glycolysis occurs in the cytoplasm and does not require oxygen or a mitochondrion, which is why it is common to nearly all cells.

Problem 4

In aerobic respiration, oxygen's role is to
  1. break glucose apart directly
  2. accept electrons at the end of the electron transport chain
  3. produce carbon dioxide
  4. supply the carbon for ATP
Answer and explanation

accept electrons at the end of the electron transport chain

Oxygen is the final electron acceptor, combining with electrons and hydrogen ions to form water, which keeps the chain running.

Problem 5

Using a stated model yield of 30 ATP per glucose for aerobic respiration and the net 2 ATP from glycolysis alone, how many times more ATP does the aerobic route recover?
Answer and explanation

15

30 / 2 = 15 times as much at this stated yield. Quote the model value used, because estimates vary with transport and coupling and no single count is universal.

Problem 6

Which equation summarizes aerobic cellular respiration?
  1. 6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
  2. C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O
  3. C₆H₁₂O₆ → 2C₃H₆O₃
  4. 6O₂ → 6CO₂
Answer and explanation

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

Glucose and oxygen are consumed and carbon dioxide and water released, with energy captured in ATP. The first choice is photosynthesis.

Problem 7

A muscle uses 2.0 × 10⁵ ATP per second aerobically. If oxygen becomes unavailable and the same glucose supply yields only one fifteenth as much ATP, how many ATP per second can be supplied, to the nearest thousand?
Answer and explanation

13000

2.0 × 10⁵ / 15 ≈ 1.3 × 10⁴, about 13,000 ATP per second — far below demand, so the muscle must slow down or consume glucose at an unsustainable rate.

Problem 8

Explain why yeast can be used to make both bread and beer, naming the process and its products.
Answer and explanation

Yeast carries out alcoholic fermentation when oxygen is scarce, converting sugar into ethanol and carbon dioxide while producing a small amount of ATP. In bread the carbon dioxide is the useful product, forming bubbles that make the dough rise, and most of the ethanol evaporates during baking. In brewing the ethanol is the useful product and the carbon dioxide may be retained for carbonation. The same process is being used for different products.

Response criteria

  • State a biologically accurate conclusion.
  • Show the data, mechanism, or calculation that supports it.
  • Include units, conditions, or limits where relevant.

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