GENETIC EXPRESSION

Nucleic acids are polymers of nucleotides, and are commonly known as DNA and RNA. DNA contains the genetic information of the cell and is contained in chromosomes in the nucleus. Genetic expression describes how the genetic code in our DNA is read, transcribed into RNA, then translated, or synthesized, into proteins. Proteins may then remain in the cell, or be secreted out of the cell.

A defect in the genetic code may cause a protein to be overexpressed, underexpressed, or completely non-functional. This is the source of genetic diseases. An error might be due to a mutation, or a mistake during DNA replication. This is why DNA repair and regulation are so important. The MCAT will test your understanding of how gene expression is regulated in eukaryotes (like your own cells), and prokaryotes, like infectious bacteria.

In the lab, using modern biotechnology, we can modify and analyze DNA with techniques like PCR, blotting, and recombination.