Curriculum

Course: Science — Second Preparatory

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Curriculum

Science — Second Preparatory

Unit 1: Matter and Energy

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Unit 2: Matter and Chemical Reactions

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Unit 3: Energy Flow in Photosynthesis and Respiration

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Unit 4: Geological Processes

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Text lesson

Cellular Respiration

Science — Second Preparatory

Cellular Respiration

Experiments and worked examples

Experiments and worked examples

Comparison aspect	Main idea	Keywords
Experiment 1: carbon dioxide from germinating seeds.	Place germinating seeds in a sealed flask and insert a tube containing clear limewater. After a few hours the limewater turns milky because the seeds respire and release carbon dioxide	Placesealedflaskinsert
Experiment 2: heat from germinating seeds.	Place germinating seeds in a vacuum flask and insert a thermometer. The temperature rises slightly because part of the energy released by respiration is converted into heat	Placevacuumflaskinsert
Experiment 3: fermentation by yeast.	Add yeast to warm sugar solution and connect the opening of the flask to a tube that passes into limewater. The limewater turns milky which shows that carbon dioxide is released	warmsugarsolutionconnect

Comparison aspect	Main idea	Keywords
Worked example	What mass of oxygen is needed for the complete aerobic respiration of 36 g of glucose? (Relative atomic masses: C = 12 H = 1 O = 16)	Whatmassoxygenneeded
Solution	molar mass of glucose = 180 g so the number of moles = 36 ÷ 180 = 0.2 mol	molarmassglucosenumber
•	From the equation 1 mol of glucose needs 6 mol of O₂ so 0.2 mol needs 1.2 mol of O₂	equationglucoseneeds

Mass of oxygen = 1.2 × 32 = 38.4 g

Comparison aspect	Main idea	Keywords
In the same way	mass of CO₂ produced = 1.2 × 44 = 52.8 g and mass of water produced = 1.2 × 18 = 21.6 g	massproducedwater
Check	36 + 38.4 = 74.4 g and 52.8 + 21.6 = 74.4 g. The two masses are equal	massesequal
•	Approximate energy released = 0.2 × 2800 = 560 kJ	Approximateenergyreleased2800

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