| Term | Definition |
|---|
| Chromosomal maintenance & propagation requires | telomere, replication origin, centromere |
| replication origin one centromere per | unreplicated chromosome |
| replication origin two centromeres per | mitotic chromosome one per chromatid |
| attachment site of kinetochore proteins | allows segregation of chromosome |
| Telomere | repetitive element that defines and protects the ends of chromosomes from loss of DNA due to "end replication" problem, added by telomerase, both protein and RNA subunits, decreased length correlated with cell senescence (when cells stop dividing) |
| Telomerase activity in most human somatic cells | little or no telomerase so that telomeres shorten as cells divide |
| Telomerase activity in Stem cells (adult and embryonic) | have telomerase |
| Telomerase activity in germline, & tumor cells | have high telomerase and telomeres maintained |
| role of chromatin proteins | package DNA in nucleus, regulate DNA replication and transcription |
| 30nm fibers held togetherr by | nuclear matrix, forms domains for global control of genes |
| Mitotic chromosome compacted by | condensin protein complexes |
| Sister chromatids held together by | cohesin protein complexes |
| Heterochromatin | Highly condensed chromatin, about 10% of genome, Transcriptionally inactive, Plays specialized functions |
| Heterochromatin specialized functions | centromeres, repetitive elements, mitotic chromosomes, boundaries |
| centromeres | chromosomal movement |
| repetitive elements | recombination, telomeres |
| mitotic chromosomes | packaging |
| boundaries | define loop domains |
| Euchromatin | Loosely folded chromatin, about 90% of genome, Two transcriptional states, active-- only ~ 10% in any given cell, this is the least condensed, inactive-- this is more condensed |
| Chromatin Changes in response to stimuli | H3 histone kinase is activated by EGF. The kinase is mutated in Coffin-Lowry Syndrome (mental retardation/ skeletal abnormalities) |
| Cloning (Dolly) proved that chromatin control is fully reversible since | nucleus from terminally differentiated somatic cell was capable of being fully reprogrammed when injected into an egg |
Combine with other sets
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