closed circular molecules, more compact and sediment more rapidly than linear formssupercoiled DNAenzymes that cut one or both DNA strands
wind or unwind helix before releasing endsTopoisomerasewhere are supercoiled DNA and topoisomerase foundeukaryotesreplication and transcription create supercoils downstream as ___double helix unwindsat interphase, eukaryotic chromosomes uncoil and decondense into a form called...chromatinduring cell division chromatin coils and condenses back into visiblechromosomescharge on histonepositivepositively charged proteins associated with chromosomal DNA in eukaryoteshistonesfive main types of histonesH1, H2A, H2B, H3, H4histones contain large amounts oflysine and argininehistone makes electrostating bonding tonegatively charged phosphate___ are condensed several times to form intact chromatidsnucleosomeschromatin structure changes to accomodate ...dna protein interactionsto allow replication and gene expression chromatin must:relax compact structure
expose regions of DNA to regulatory proteins
have a reversal mechanism for inactivityDNA ___ encircle histonessuperhelixunconstructed ___ are not packed into folded histone domains within nucleosomeshistone tailstails devoid of secondary structure protrude through..minor groovemodification that is important to genetic functionchemical modificationshistone tails provide targets along chromatin fiber for...chemical modificationslist three chemical modificationsacetylation, methylation, phosphorylationThe enzyme histone acetyl transferase _____________ (abbreviation)HATaddition of acetyl group to positively charged amino group on side chain (lysine) changes net charge of protein by neutralizaing positive chargeacetylationenzyme for methylationmethyltransferaseadds methyl groups to arginine and lysine residues in histonesmethylationdoes methylation have a positive or negative correlation with gene activitypositiveenzyme for phosphorylationkinaseadds phosphate groups to hydroxyl groups of amino acids serine and histidinephosphorylation____ of nitrogenous base cytosine w/in polynucleotide chains of DNAmethylationdoes methylation of cytosine positive or negative correlation with gene activitynegativemethylation of cytosine forms5 methyl cytosineregion of DNA where many cytosine guanine dinucleotides are presentCpG islanduncoiled and active
appears unstained during interphaseeuchromatincondensed areas are mostly inactive
appears stained during interphaseheterochromatinheterochromatin is genetically ___
lacks genes or contains repressed genesinactiveheterochromatin replicates later in
___ than euchromatinS phase____ maintain chromosome integritytelomere___ involved in chromosome movementcentromeredifferential staining along longitudinal axis of mitotic chromosomechromosome banding techniquemitotic chromosomes have a characteristic banding pattern
-only centromeres/heterochromatin take up stainc bandingdifferential staining along length of each chromosomeg bandingdigestion of mitotic chromosome by enzymeg bandingnomenclature for human chromosome banding is based ong bandingnomenclature for human chromosome banding is applied to which chromosomexregions of the x chromosome are distinguished by itsbanding patternDNA sequences are repeated many times withineukaryotic chromosomehighly repetitive and consists of short repeated sequences
makes up variable portion of total DNAsatellite DNAwhere are satellite dna foundheterochromatic centromeric regions of chromosomesare satellite dna found in prokaryotesnoseparation of homologs during mitosis and meiosis depends on ...centromeresalong with eukaryotic chromosomes, ___ are the primary constrictionscentromeresregion that binds to spindle fiber microtubules during cell divisionkinetochore proteinsModerately repetitive DNA includesVNTRs, minisatellites, microsatellitesmicrosatellits are alsoSTRsSTRsshort tandem repeatsVNTRsvariable number of tandem repeatsrepeating DNA sequences 15 to 100 bp longVNTRswhere are VNTRs foundwithin and between genesTandemly repeated sequences
dispersed throughout genome
consists of di, tri, tetra, and pentanucleotidesmicrosatellites (STRs)LINESlong interspersed elementsSINESshort interspersed elementstransposable sequences that are mobile and can relocate within genomeSINES and LINESdispersed throughout genome rather than tandemly repeatedSINES and LINESconstitutes 1/3 of human genomeSINES and LINEStransposable elements generated via RNA intermediate (LINES)retrotransposons% of eukaryotic genome that constitutes protein encoding genes2-10large number of single copy non-coding regionspseudogenesDNA sequences representing evolutionary vestigespsudogenespseudogenes have undergone significant ___mutational alterationsare pseudogenes transcribedno
