lesson
Not every cell has a nucleus
1 · Learn
Eukaryotic cells have genetic material enclosed in a nucleus; prokaryotic cells such as bacteria do not have a membrane-bound nucleus. Both have a cell membrane, cytoplasm, ribosomes and genetic material. Plant cells also have features such as a cellulose wall and often chloroplasts.
A simplified diagram is not a scale drawing. Avoid calling bacteria featureless or assuming every plant cell contains chloroplasts; specialised cells differ.
2 · Worked example
A root hair cell is a plant cell but normally lacks chloroplasts because its role and location differ from a photosynthetic leaf cell.
3 · Your turn
Does a bacterial cell lack genetic material because it has no membrane-bound nucleus?
Check your answer
No. Its genetic material is present but not enclosed in a membrane-bound nucleus.
4 · Apply your learning
Compare labelled approved diagrams and connect each feature to a function rather than memorising colours.
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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Follow your teacher's approved method and safety instructions. Record the sample or supplied dataset, conditions, measurements with units and uncertainties where appropriate. Distinguish observations from explanations. A described experiment is not permission to carry it out; do not improvise equipment or invent missing results.
Ask your teacher for support with the method and recording. A prediction is what you think might happen; an observation is what you actually see, hear or feel safely.
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Year 10 Science learning routine
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