Structure, function and growth of prokaryote and eukaryote cells

1
Structure, function and growth of prokaryote and
eukaryote cells

• (iii) Differentiation of cells
• into tissues and organs.
• (iv) Cell and tissue culture
• Mammalian cell cultures
• Bacterial and Fungal
• Cultures
• (v) Plant tissue culture

2
Plant Tissue Culture

• Plant tissue culture is used to create clones.
• This is useful
• To create pathogen free species
• Create crop species that have identical traits
  (e.g. height)
• Save endangered species
• Somatic Fusion (Protoplast hybridisation) is used
  to create new varieties.
• Plant tissue culture is then used to grow the
  plant

3
Somatic Fusion

• Cells from two different plants are selected
• Cell wall is removed using cellulase and
  pectinase
• Protoplasts are fused using either
• Polyethylene Glycol
• Electrical shock
• Protoplast is grown using tissue culture

4
Plant Tissue Culture

• Source of cell / tissue
• Small pieces of tissue are taken from a plant.
  These are called explants.
• Protoplast from somatic fusion.
• Plant cells / tissue have a long life span
• Suitable container
• Anything sterile (the entire procedure must be
  carried out under aseptic conditions).

5
Plant tissue culture cont

• Growth Medium
• Simple (can be liquid or solid) containing carbon
  source, minerals salts, water, vitamins
• Contains plant growth regulators to cause tissue
  differentiation e.g.
• Cytokinins promote shoot development
• Auxins promote root development

6
Plant tissue culture cont

• Events in Plant Tissue culture
• Explant is removed and sterilised.
• It is transferred to growth media
• A mass of undifferentiated cells called the
  callus forms (this occurs due to auxin and
  cytokinin concentrations being balanced).
• Tissue is transferred to growth media containing
  different concentrations of growth regulators to
  promote shoot and root production.
• Tissue culture plants acclimatised in greenhouses.

7
Totipotency

• Totipotency is the cells ability to
  differentiate.
• In theory, all cells have this potential as they
  have the same genome (nuclear totipotency)
• In practise,
• Plant cells are totipotent
• Mammalian cells vary
• e.g. Stem cells are totipotent

8
Learning Activities

• Dart pg 23 24
• Scholar (Unit 1, 3.4 3.6)
• Plant Tissue Culture
• Advanced Higher Biology Questions
• Create a table to compare the 3 types of tissue
  culture
• Create flow diagrams of the tissue cultures
• Create a glossary