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

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

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

Plant Tissue Culture Source of cell / tissue Suitable container 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).

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

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.

Totipotency Totipotency is the cell’s 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

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