This document discusses the structures and components of animal and plant cells, including mitochondria, nucleus, and chloroplasts. It also explains DNA extraction from cells, involving removal of proteins and RNA. The document further describes different forms of DNA (A, B, and Z-forms), transcription of DNA into mRNA, and translation of mRNA into proteins. It notes that prions are replicating proteins. The levels of protein structure - primary, secondary, tertiary, and quaternary - are also outlined.