1.1 - Division and Differentiation

  • Created by: TieganR
  • Created on: 05-01-22 17:21

1.1 a) Division of Somatic / Germline Cells

  • Somatic stem cells divide by mitosis for more somatic cells
  • Germline stem cells divide by mitosis and mieosis

- Mitosis produces more Germline stem cells and Mieosis produces haploid gametes

  • Mitosis - 2 diploid daughter cells, maintains chromosome complement, produce cells for self-renewal/ growth ad repair, somatic and germline

1. chromosomes in nucelus copied and chromosomes condense and form 2 identical chromatids

2. nucleus disintegrates and spindle fibres line chromatids at equator

3. chromatids separate and move to opposite sides of the cell

  • Mieosis - 4 haploid daughter cells, produces gametes and reproductive cells, germline

1. chromosomes in nucleus copied and chromosomes condense and form 2 identical chromatids

2. Chromosomes find match, exchange DNA , nuclues disintegrates, spindle fibres make chromatids line at equator

3. 1st division -> matching pairs separate, 2nd division -> separate into 4

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1.1 b) Cellular Differentiation

  • Cellular differentiation is when a cell expresses certain genes to produce characteristics of that cell
  • Allows cell to have specialised functions
  • Embryonic stem cells - can turn into all cell types, pluripotent
  • Tissue stem cells - used for growth and repair, can only turn into cells into that tissue, multipotent
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1.1 c) Stem Cells

  • Therapeutic uses - repair of damaged and diseased tissues/ organs

- cornea repair

- skin graft for burns

  • Research uses - stem cells are used as model cells to study how diseases develop or used for drug testing

- Differentiation

- Cell growth

  • Ethical Issues

- Destruction of embryos

-Loss of potential human life

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1.1 d) Cancer Cells

  • Divide excessively and don't respond to regulatory signals in the cell cycle
  • Mass of abnormal cells = tumour
  • Cells in tumour may fail to attach to the surface and spread through the body causing a secondary tumor

- Also known as a metastatic growth

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