sci_bio
Cell Structure
Chapter summary, hard words and model exam answers for ICSE Class 10 Hindi.
Free online summary and notes (ICSE Class 10 Hindi). Read it here, no PDF download needed.
About the author
Biology · CBSE 10 · ICSE 10 · GCSE (AQA, Edexcel, OCR)
Summary
Robert Hooke first saw cells in cork in 1665. The cell theory says all organisms are made of cells and every cell comes from an existing cell.
Bacteria are prokaryotic - their DNA floats free, with no membrane-bound organelles. Plant, animal and fungal cells are eukaryotic and far more organised.
Both share a nucleus, cytoplasm, membrane, mitochondria and ribosomes. Plants add a cellulose cell wall, chloroplasts for photosynthesis and a large central vacuole.
Small molecules like oxygen cross by diffusion and water by osmosis. The cell wall, by contrast, is fully permeable and only gives support.
Hard words & meanings
| organelle | a specialised structure inside a cell that carries out a particular function |
| nucleus | the organelle that holds the DNA and controls the cell's activities |
| mitochondrion | the organelle where aerobic respiration releases energy from glucose |
| ribosome | a tiny structure that builds proteins from amino acids |
| chloroplast | a green organelle containing chlorophyll where photosynthesis occurs |
| vacuole | a fluid-filled sac; large and permanent in plant cells, storing cell sap |
| selectively permeable | allowing some substances to pass through while blocking others |
| eukaryotic | a cell with a true membrane-bound nucleus and organelles |
Model exam answers, grammar & audio
You have read the summary. The board-ready model answers, grammar notes, one-touch audio and writing practice for this chapter are part of Lipi©.
Sign in to unlockSee it, understand it, hear it read aloud, then write the exam answer with confidence, for a fraction of a tutor cost.