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WVSOM -- Genetics
Chromosomal Structure
| Question | Answer |
|---|---|
| Supercoiling | When the two strands of DNA are twisted around each other they coil up. |
| Chromatin | DNA plus protein. |
| Heterochromatin | highly condensed, darkly staining chromatin |
| Euchromatin | less dense, lightly staining, transcriptionally active, chromatin. |
| Solenoid coiling | Nucleosomes will wrap around each other to form tubes |
| Histones | proteins that form octameric complexes, which eukaryotic DNA wraps around. They are the most abundant |
| Nucleosomes | histone octamers and associated DNA, not including the linker regions |
| Histone 1 (H1) | binds linkers together |
| Histones are acids or bases? | bases! They are positively charged molecules |
| Solenoid tangling | Chromosomal condensation during prophase also involves solenoids tangling in complex patterns to form the mitotic (or meiotic) chromosomes. |
| Scaffoid Proteins | Ties the solenoids together to form the condensed, mitotic chromosomes. Maintain supercoiling |
| Bands in mitotic chromosomes | dark staining regions, which are believed to consist of more tightly packed DNA. |
| Structure of Mitotic (Meiotic) Chromosomes | Bands Centromeres Arms Telomeres |
| Centromere | Region of a chromosome that is bound to the mitotic spindle. Dark bands are called G bands |
| metacentric chromosome | central centromeres |
| Submetacentric chromosome | off center centromere |
| Acrocentric | Centromere towards end with a satellite at the end |
| Telocentric | Centromere at the end. not found in humans |
| Arms | chromosomes are divided by the centromere into two regions known as arms. Shorter arm is p arm (petite) Larger arm is q arm |
| Telomeres | The ends of chromosomes |
| Karyotype | Number, size and banding patterns of all mitotic chromosomes. |
| Karyotype numbers | Larger to smaller |