Doc Brown's GCSE OCR 21st Century Science-Biology Revision Notes

PLEASE NOTE NEW revision summaries for the NEW OCR 21st Century Science B GCSE Biology B and NEW OCR GCSE 21st Century Combined Science B Biology courses: Revision for Chapters 1-3) and  Paper 2 (Chapters 4-6) STARTING with Y10 in Sept. 2016 onwards, first exams in 2018

OCR GCSE 21st Century Additional Science Biology Module B5 Growth and development

B5.1 How do organisms develop?

  • 1. know that cells in multicellular organisms can be specialised to do particular jobs

  • 2. know that groups of specialised cells are called tissues, and groups of tissues form organs

  • 3. know that a fertilised egg cell (zygote) divides by mitosis to form an embryo

  • 4. know that in a human embryo up to (and including) the eight cell stage, all the cells are identical (embryonic stem cells) and could produce any type of cell required by the organism

  • 5. understand that after the eight cell stage, most of the embryo cells become specialised and form different types of tissue

  • 6. understand that some cells (adult stem cells) remain unspecialised and can become specialised at a later stage to become many, but not all, types of cell required by the organism

  • 7. understand that in plants, only cells within special regions called meristems are mitotically active

  • 8. understand that the new cells produced from plant meristems are unspecialised and can develop into any kind of plant cell

  • 9. understand that unspecialised plant cells can become specialised to form different types of tissue (including xylem and phloem) within organs (including flowers, leaves, stems and roots)

  • 10. understand that the presence of meristems (as sources of unspecialised cells) allows the production of clones of a plant from cuttings, and that this may be done to reproduce a plant with desirable features

  • 11. understand that a cut stem from a plant can develop roots and then grow into a complete plant which is a clone of the parent, and that rooting can be promoted by the presence of plant hormones (auxins)

  • 12. understand that the growth and development of plants is also affected by the environment, eg phototropism

  • 13. understand how phototropism increases the plant’s chance of survival

  • 14. HT only: be able to explain phototropism in terms of the effect of light on the distribution of auxin in a shoot tip.




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