lesson
Respiration occurs inside living cells
1 · Learn
Cellular respiration transfers energy through chemical reactions so cells can carry out processes such as active transport and synthesis. Aerobic respiration uses oxygen; anaerobic pathways differ between organisms and release less energy per glucose in the usual comparison.
Breathing moves air and supports gas exchange, but it is not the same process as cellular respiration. Plants respire as well as photosynthesise.
2 · Worked example
A plant cell can carry out respiration at night when photosynthesis is not occurring, using stored organic material.
3 · Your turn
Is respiration restricted to animals? Explain.
Check your answer
No. Plants and many other organisms also carry out cellular respiration.
4 · Apply your learning
Compare word equations supplied by a teacher and identify the different reactants and products without equating respiration with ventilation.
Adult guidance and safety
Use supplied data and approved diagrams. Laboratory work requires qualified supervision, suitable equipment and a risk assessment. No independent chemical, electrical, heating, radiation or biological-culture experiments. Human biology is general education, not personal diagnosis or treatment.
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Check a calculation · Year 5 onward
Use this only when your teacher or adult allows a calculator for the task. Show your thinking first. It does not replace mental or written arithmetic and does not mark your lesson answer.
Powers, roots and trigonometry · Year 7 onward
Use only when the task allows a calculator. Choose one operation at a time and record your working. Trigonometry here always uses degrees (DEG), not radians. Inverse sine, cosine and tangent return an angle, not a reciprocal. Keep exact fractions and π in answers when requested.
Approximate numerical results use up to 12 significant digits. Inverse sine returns −90° to 90°, inverse cosine 0° to 180°, and inverse tangent −90° to 90°; these are principal values, not every possible solution of a trigonometric equation.
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