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S4 Biology: Cellular Respiration Paper 1 (Foundation)
S4 Biology: Cellular Respiration Paper 1 (Foundation)
Read whether each item asks for a location, a product or a quantity. This paper covers the equation, stage locations and anaerobic products.
Quick answer 1. 12 O2, 12 CO2 | 2. cytoplasm / matrix / inner membrane | 3. lactate | 4. ethanol and CO2 | 5. 6.7% | 6. RQ 1.0 | 7. +50% | 8. 120 cm3 | 9. 7.2 cm3 | 10. glycolysis still gives 2 ATP
01 Paper details (check answers afterwards)
| Item | Detail |
|---|---|
| Questions | 10 questions |
| Suggested time | 25 minutes |
| Difficulty mix | Foundation 4 · Intermediate 3 · Challenge 2 · Error redo 1 |
| Chapter | Chapter: S4 Biology — Cellular Respiration |
| Level | Foundation |
02 Questions (10 items)
- FoundationComplete oxidation of 2 glucose molecules needs how many oxygen molecules and releases how many carbon dioxide molecules?
- FoundationWhere in the cell do glycolysis, the Krebs cycle and the electron transport chain take place?
- FoundationWhen human muscle runs short of oxygen during hard exercise, glucose is broken down into what?
- FoundationWhich two substances does yeast produce when it breaks down glucose without oxygen?
- IntermediateAerobic respiration yields a net 30 ATP per glucose, of which glycolysis gives a net 2. What percentage comes from glycolysis (1 d.p.)?
- IntermediateA tissue uses 400 cm3 of oxygen and releases 400 cm3 of carbon dioxide in 10 minutes. What is its respiratory quotient and main substrate?
- IntermediateThe same tissue produces 24 bubbles per minute at 25 C and 36 at 35 C. By what percentage does the rate rise?
- ChallengeFermentation uses 0.90 g of glucose (Mr 180). At a molar volume of 24.0 dm3/mol, what is the maximum volume of carbon dioxide in cm3?
- ChallengeA 0.50 g sample uses 1.2 cm3 of oxygen in 20 minutes. Find the oxygen uptake per gram per hour.
- Error redoA student claims anaerobic respiration produces no ATP at all. Where is the error?
03 Answers and one-line notes
| # | Answer | One-line note |
|---|---|---|
| 1 | It needs 12 oxygen molecules and releases 12 carbon dioxide molecules. | Each glucose molecule uses exactly six oxygen molecules and releases six carbon dioxide molecules. |
| 2 | Glycolysis in the cytoplasm, the Krebs cycle in the mitochondrial matrix, the chain on the inner membrane. | Location fixes the hydrogen route, which explains why only glycolysis survives without oxygen. |
| 3 | It is converted into lactate. | Accumulated lactate causes fatigue and still needs oxygen afterwards. |
| 4 | It produces ethanol and carbon dioxide. | This is exactly the basis of brewing and bread making. |
| 5 | It accounts for 6.7%. | Percentage = 2 / 30 x 100; the rest comes from oxidative phosphorylation. |
| 6 | RQ = 1.0, so the main substrate is carbohydrate. | The respiratory quotient of carbohydrate is close to 1.0. |
| 7 | It rises by 50.0%. | Rise = (36 – 24) / 24 x 100. |
| 8 | That is 0.005 mol of glucose, giving 120 cm3 of carbon dioxide. | Find moles from mass first, then multiply by molar volume to get cm3. |
| 9 | It is 7.2 cm3 per gram per hour. | Convert 20 minutes to one hour first, then scale by mass. |
| 10 | Glycolysis still gives a net 2 ATP; only the large output of the chain is missing. | Anaerobic yield is small but never zero. |
04 What to do after marking
- After marking, redo only the wrong items and write down which step went wrong (formula, unit, or misread number).
- Repeat the same item two days later; move to the next paper only when both attempts are correct.
- Parents only need the answer and note columns; there is no need to explain every item.
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