The table below summarises the main functions of the major cell organelles:
| Organelle/macromolecule | Main function |
|---|---|
| Endoplasmic reticulum | Rough endoplasmic reticulum |
| • translation and folding of new proteins | |
| • manufacture of lysosomal enzymes | |
| • site of N-linked glycosylation | |
| • examples of cells with extensive RER include pancreatic cells, goblet cells, plasma cells |
Smooth endoplasmic reticulum • steroid, lipid synthesis • examples of cells with extensive SER include those of the adrenal cortex, hepatocytes, testes, ovaries | | Golgi apparatus | Modifies, sorts, and packages these molecules that are destined for cell secretion The addition of mannose-6-phosphate to proteins designates transport to lysosome | | Mitochondrion | Aerobic respiration. Contains mitochondrial genome as circular DNA | | Nucleus | DNA maintenance RNA transcription RNA splicing • the process that removes the intervening, non-coding sequences of genes (introns) from pre-mRNA and joins the protein-coding sequences (exons) | | Lysosome | Breakdown of large molecules such as proteins and polysaccharides | | Nucleolus | Ribosome production | | Ribosome | Translation of RNA into proteins | | Peroxisome | Catabolism of very long chain fatty acids and amino acids Results in the formation of hydrogen peroxide | | Proteasome | Along with the lysosome pathway involved in degradation of protein molecules that have been tagged with ubiquitin |