Key Concepts of Section 4.1

• Animal cells have to be grown in culture under conditions that mimic their natural environment, which generally requires them to be supplied with necessary amino acids and growth factors.

• Most animal cells need to adhere to a solid surface to grow.

• Primary cells—those isolated directly from tissue—have a finite life span.

• Transformed cells, such as cells derived from tumors, can grow indefinitely in culture.

• Cells that can be grown indefinitely are called a cell line.

• Many cells lines are aneuploid, having a different number of chromosomes than the parent cell from which they were derived.

• Cells expressing a fluorescent protein can be sorted on a machine called a fluorescence-activated cell sorter (FACS).

• Different cell types express different marker proteins on their cell surfaces, which can be labeled with fluorescent markers, allowing them to be sorted on a FACS machine.

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• Epithelial cells are often grown is special containers to mimic their functional polarity. Cells can also be grown on three-dimensional matrices to more accurately reflect their normal environment.

• Monoclonal antibodies, which bind one epitope on an antigen, can be secreted by cultured cells called hybridomas. These hybrid cells are made by fusing antibody-producing B lymphocytes with immortal myeloma cells and then identifying those clones that produce the desired antibody. Monoclonal antibodies are important for basic research and as therapeutic agents.

• Cells in culture can be much more easy manipulated than cells in an intact animal.

• Basic biological processes can be studied by interfering with specific cell components, either through genetic mechanisms or by the application of specific drugs.

• Large chemical libraries can be screened for compounds that target specific processes to study those processes and to identify new drugs.