Biology / Unit 6: DNA and Protein Synthesis
6.6 Gene Expression and Biotechnology
Notes
Every body cell has the same DNA, but each cell type uses (expresses) different genes.
- Gene regulation turns genes on or off. In bacteria, the lac operon turns on lactose-digesting genes only when lactose is present.
- Cell differentiation happens because different genes are expressed in different cells.
- Genetic engineering changes an organism's DNA. Bacteria with a human insulin gene make insulin for people with diabetes.
- Gel electrophoresis separates DNA pieces by size (small pieces move farther) for DNA fingerprinting.
- PCR makes many copies of a DNA sample. CRISPR is a tool that edits specific genes.
Practice
A nerve cell and a muscle cell from the same person look and act differently because they:
They have the same DNA but turn on different genes.
In gel electrophoresis, which DNA fragments travel farthest through the gel?
Small fragments slip through the gel more easily.
Scientists insert the human insulin gene into bacteria, which then make human insulin. This works because:
Bacteria read the human gene's codons the same way human cells do.
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