The cells quickly cover the bottom of the flask from where they can be removed for experimental work
The Hayflick Limit: Most cultured cells will usually grow 30-40 generations
Laboratory or (in vitro) techniques enable tissue cultures to be grown in a lab and safely stored for many years

Plant Tissue Culture

Techniques for plant tissue culture:

Select healthy cells from actively growing tissue (eg buds, leaf tips)
Wash in a sterilising solution (hypochlorite) to remove any contaminating bacteria or fungi
Place on sterile growing media (usually an agar gel). The growing media should contain all the materials required for growth growth hormones and nutrients such as minerals
Incubate in a stable warm light environment
The tissue will develop into a thallus and eventually leaves and roots will develop. The tissue can then be further divided or planted out

Thallus Definition: a plant body that lacks differentiation into distinct parts (as stem, leaves, and roots)

Application:

Plant tissue culture is used in agriculture to produce large numbers of genetically identical plants to improve the consistency of plants. Depending on the concentration and type of hormones used the tissue can be made to divide/differentiate into roots or shoots or both.
This technique is used to clone valuable plants

Animal Tissue Culture

Techniques for animal tissue culture:

Select healthy growing cells and sterilise the surface of the tissue sample
Separate the cells by adding enzymes. This overcomes any contact inhibition
Place in a sterile nutrient solution (containing glucose, amino acids, minerals and growth hormones) and incubate at body temperature
At intervals it will be necessary to remove cells to allow the remaining cells to divide
Cultured cells are kept at optimal temperatures and will grown and divide for 30-40 generations.

Application:

This technique is used to grow skin for burn victims and one day may be used to grow new organs for transplant
Used widely in medicine to provide skin tissue and reserve cells for organs
Used instead of live animals for testing cosmetics and drugs

Difficulty:

Unlike bacteria and plant cells, animals cells are unable to synthesise most of their requirements from simple compounds in the culture medium. All vitamins and other necessary organic compounds must be supplied and the osmotic balance and temperature carefully monitored. The medium must be aerated unless grown as a monolayer.
Bioethics is the study of what controls should be placed on the use of cell cultures, such as growing human embryos without a womb

	Created by gbridgland almost 10 years ago

Year 12 Biology Note on Yr 12 Biology Mid-Year Exam Notes Part 1, created by gbridgland on 06/06/2014.

Yr 12 Biology Mid-Year Exam Notes Part 1