ESSAY QUESTIONS

• give an account of cell differentiation under the following heading: STEM CELLS

  1. differentiation occurs when unspecialised cells become specialised to perform a specific function
  2. stem cells are unspecialised cells that can divide to form more stem cells
  3. embryonic stem cells can differentiate into all cell types
  4. tissue stem cells give rise to a limited range of cell types
  5. stem cells in bone marrow only produce blood cells
  6. a differentiated cell only has a few genes switched on
• give an account of cell differentiation under the following heading: SOMATIC CELLS

  1. somatic cells are any body cells not involved in reproduction
  2. somatic cells divide by mitosis to form more somatic cells
  3. during mitosis the nucleus of the cell divides to maintain the diploid chromosome number
  4. diploid cells have 23 pairs of homologous chromosomes (2 sets)
• give an account of cell differentiation under the following heading: GERMLINE CELLS

  1. germline cells are the gametes (sex cells) and the stem cells which divide to form the gametes
  2. germline cells are diploid and can divide by mitosis to produce more diploid germline cells or divide by meiosis to produce haploid gametes
  3. haploid cells have 23 chromosomes (1 sets)
• Write notes on stem cells under the following headings: TYPES OF STEM CELLS

  1. stem cells are unspecialised somatic cells
  2. capable of mitosis to create copies of themselves
  3. stem cells can differentiate into specialised cells
  4. there are 2 types: embryonic + tissue
  5. embryonic stem cells are pluripotent
  6. tissue stem cells are multipotent
• Write notes on stem cells under the following headings: RESEARCH AND THERAPEUTIC USES

  1. tissue stem cells produce cells needed for growth and repair
  2. once differentiated, cells only express certain genes
  3. genes produce proteins characteristics for that type of cell
  4. therapeutic use of stem cells to repair damaged/ diseased tissues
  5. eg corneal tissue to repair damaged cornea to restore sight
  6. embryonic stem cells research can provide a culture of stem cells which can be used as model cells
  7. used for drug testing
• Types of stem cells and ii. RESEARCH AND MEDICAL uses:

  1. Stem cells are unspecialised/undifferentiated somatic cells
  2. Capable of mitosis/self-renewal to create copies of themselves
  3. Stem cells can differentiate into specialised cells
  4. There are two types: Embryonic and Tissue
  5. Embryonic stem cells are pluripotent
  6. Tissue stem cells are multipotent