Tissue Culture Unit one Cell and Molecular Biology Advanced Higher Biology
Dec 28, 2015
Tissue Culture
Unit oneCell and Molecular Biology
Advanced Higher Biology
Arrangements Differentiation of cells into tissues
and organs.
• Cells undergo differentiation to become specialised cells that are organised into tissues and organs.
• Cellular differentiation depends on changes in gene expression resulting in genes being switched on and off
Arrangements Cell and tissue culture
• The ability of stem cells to differentiate, unlike specialised cells.
• The lac operon in E.coli.– Repressor molecule, – regulator gene, – inducer, – operator– structural gene
Arrangements Mammalian cell culture.
• Requirement of aseptic conditions, solid surface, growth factors and nutrients in complex growth media.
• Use case studies to illustrate the applications of cell culture.
Arrangements Mammalian cell culture.
• The addition of animal serum such as fetal bovine serum (FBS) to promote cell proliferation and antibiotics to prevent bacterial growth. – Use of proteolytic enzymes to release
cells from source tissue. • Cells adhere to the surface, spread out
and divide until a monolayer is formed and the cells are confluent.
Arrangements Mammalian cell culture.
• Difficulty in maintaining cultures of mammalian cells due to cells dying after a finite number of divisions in culture.
• Cell lines prepared from cells which undergo a genetic change that makes them immortal or from cancer cells. A clone is the result of cell cloning in which a single cell is isolated and allowed to proliferate to form a large colony.
Arrangements Bacterial and fungal cultures • The advantages of the simpler
growth media requirements and culture conditions for bacteria and fungi compared to mammalian cells.
ArrangementsPlant tissue culture.
• Techniques used (including requirement for aseptic conditions and suitable growth medium).
• Growth of explants on suitable media to produce a callus.
• The use of growth regulators such as auxins and cytokinins to cause tissue differentiation.
ArrangementsPlant tissue culture.
• Production of pathogen-free plantlets and plants, generation of new varieties of plants and use in plant propagation.
• Use of terms protoplast and totipotent.
• Examine photographs of protoplasts at different stages of culture and as fusion products.
Differential gene
expression in developmentNeeded in similar depth to that
taught at Higher Biology
Revision Questions
• Name the process in which DNA is copied into RNA.
• Name the process in which RNA is read into protein
• What is a transcription factor?
Revision Questions
• Name the process in which DNA is copied into RNA.– transcription
• Name the process in which RNA is read into protein– translation
• What is a transcription factor?– A protein that interacts with RNA
polymerase, or other transcription factors, to regulate gene expression.
Control of gene expression
• Temporal• Spatial
• Drosophila melanogaster– Fruit fly– Used in studies
Development in Drosophila
Egg to organism
Mouse
Cell and Tissue Culture
Four major applications
• agriculture • pharmaceuticals • food production • biodegradation
Conditions for growth• a source of suitable cells; • the growth medium; • the type of growth container or
fermenter; • temperature; • pH; • gas exchange • aseptic conditions; • a method for monitoring cell growth; • safety measures
Data interpretation• Assume that bacterial cells have a
doubling time of 30 minutes, and that mammalian cells have a doubling time of 24 hours.– Calculate the number of cells that would
exist after one day of growth if you start with one cell in each culture.
– For the bacterial culture only, draw a graph to show the pattern of growth for the first 4.5 hours.
– Explain why the bacterial growth achieved after one day is unlikely to be achieved in practice.
Micro-organisms
• Categories of Micro-organisms– bacteria; – fungi; – protozoa; – algae.
• Microorganisms are relevant to many aspects of human existence– examples
Growth requirements
• nutrient medium • temperature• pH• gaseous environment• light
Bacterial Culture• Revision of bacterial growth
Questions• In which phase are the bacteria
dividing at a constant rate?• In which phase does the rate of cell
division equal the rate of cell death?• In which phase are the bacteria
metabolically active but not dividing?
• In which phase does bacterial cell death exceed cell division?
Mammalian Cell Culture
• More carefully controlled growth conditions
• Anchorage dependent–Monolayer– Confluence sub-culturing
• Non-anchorage dependent– E.g. blood– Grown in suspension
Growth medium
• Balanced salt solution with amino acids, glucose and vitamins
• Serum e.g. fetal bovine serum– Essential for animal cell proliferation– Usually 5-10% FBS
Primary cell culture
• Tissues treated with a proteolytic enzyme to separate cells from each other.
• Normal cells – finite division• Immortalised cell lines– E.g. cells derived from tumours– neoplastic
Uses of cell cloning
• Isolation of mutant cells• Investigating cell growth• Biotechnology– Vaccines– hormones
Plant Tissue Culture
• Nuclear totipotency– Plant cells have ability to regenerate
complete plants under appropriate conditions.
Plant tissue cultureexplant
Grown in media containing plant growth regulators
Cell proliferation
Callus
Sub-cultureChange growth regulators
Differentiation roots and shoots
Hybrid Plant cells
• Protoplast fusion– Revise• Formation of protoplasts• Growth of protoplasts
Essay• Discuss the requirements for the growth of microbial cells and describe, with the aid of a labelled diagram, the pattern of growth of a batch culture of microbial cells.