| A | B |
|---|
| Cyclins | Proteins that rise and fall in concentration in step with the cell cycle. |
| Cyclin-dependent kinases (Cdks) | Kinases that trigger different steps in the cell cycle. Cyclins neccessary for activation.Concentration rather stable. |
| Rb | Tumor suppressor gene. Inactivates the gene regulatory protein E2F. One inherited bad allele causes retinoblastoma. |
| p53 | Tumor suppressor gene. Halts cell cycle or starts apoptosis as response to DNA damage. Mutated in half of all human cancers. |
| DNA replication checkpoint | Checkpoint in cell cycle that delays entry into mitosis until entire genome has been copied. |
| Spindle-attchment checkpoint | Checkpoint in cell cycle that delays entry into anaphase until all chromosomes are attached to the spindle. |
| DNA damage checkpoints | Checkpoints in cell cycle that delay entry into S phase resp. mitosis in case of DNA damage. Former dependent on p53. |
| Caspases | Family of intracellular proteases that perfoms key steps in apoptosis. Synthesized as the inactive precursors procaspases. |
| Cytochrome c | Protein in mitochondria. Initiates apoptosis when released to cytosol. Release is controlled by the Bcl2-family of proteins. |
| Mitogens, growth factors, survival factors | Classes of factors that promote organ or organism growth. |
| Telomeres | DNA sequence and ass. proteins at ends of chromosomes. DNA shortened during proliferation unless telomerase active. |
| Proto-oncogenes, oncogenes | Former are normal genes, that usually control cell cycle. Latter are mutated cancer-promoting forms of former. |
| Tumor suppressor genes | Normal genes that usually inhibits cells proliferation. Mutation is reccessive on cellular level. |
| Myc | Family of proto-oncogenes that promote cell proliferation. |
| Chromatin | Complex of DNA, histones and nonhistone proteins in the nucleus of eucaryotic cell. |
| Nucleosome | Two of each of the histones H2A, H2B, H3 and H4 together with about 200 bp of DNA (incl. linker) forms a nucleosome. |
| Chromatine remodeling complex | Protein machines that help change the structure of nucleosomes, e.g., in connection with transcription. |
| Histone acetyl transferases (HATs) | Enzyme that transfers acetyl groups to histone tail. This masks the postive charge of histones and thereby decondenses the DNA. |
| Heterochromatin, euchromatin | Euchromatin is "normal" chromatin, whereas heterochromatin is unusually condensed and transcriptionally inactive. |
| Histones | Proteins in nucleus of eucaryotes, that help organize DNA. Has positive charges that neutralizes negative DNA. Large quantities. |
