Question

The basic unit of life is the cell, and now in a modern laboratory even mammalian cells can be easily cultured in a test tube or a flask. In this unit you have learned about the biomolecules of life such as carbohydrates, lipids, proteins and nucleic acids which come together to allow cells to form and function. You are required to design a cell culture medium for maintaining mammalian cells, what are your key considerations? (hint: you need to describe the key nutrients and the underlying reason for them, and the pH of your medium).

Answer 1

Growing mammalian cells in a lab is a tedious process and defining its growth media is more complex. Defining a growth medium requires the knowledge of the cell type, cultural environment in which cells grow. Apart from basic growth requirements specific cell lines need different hormones or growth factors to perform a particular function.

Basic cell culture components requirements.

1. Glucose- It acts as a primary carbon source and can be utilised in glycolysis to form ATP and fulfill the energy requirement.
2. pH- Medium should be maintained at 7.4 pH as most of the protein exists in a zwitter ionic form. Most of the Culture medium components are more stable at neutral pH.
3. Salt- Generally used as ionic balance and some are used as buffering agents.

Sodium chloride, Potassium Chloride, Magnesium sulphate, Calcium nitrate maintain ionic balance as well as fulfill cofactor requirements for proteins. where Sodium Bicarbonate acts as a buffering agent and maintains the pH at 7.4.

1. Amino acids- All essential and nonessential amino acids should be simply supplemented in a culture medium for the synthesis of proteins.
2. Vitamins- All vitamins should be added in a culture medium but the more essentials are vitamin B complex that are generally required as cofactors in proteins and some intermediates in other biological processes.
3. Serum- Cell division requires growth factors and other components that are supplemented by serum. Fetal bovine serum are effective replacements for these factors.
4. Antibiotics- Cell lines are prone to contamination and we have to add antibiotics to stop growth of bacteria, mycoplasma and fungi.

The above seven are the key components of the basic requirement for culture of mammalian cells in the lab.