Genome Organisation Flashcards
How is prokaryotic genetic material organized?
supercoiled structure with nucleoid associated proteins to help structure DNA
How is eukaryotic genetic material organised?
organised in chromosomes enclosed in the nucleus
what are nucleosomes composed of?
8 positively charged histones with DNA wrapped around them
how are chromatin packaged?
linear DNA, nucleosome, histones, loops, chromatid
what is euchromatin?
less densely packaged chromatin occupies most of the nucleoplasm
what is heterochromatin?
tightly packed chromatin found in centromere and telomers
what are telomeres?
protects ends of chromosomes, specialised origins of replication that allow the cell to replicate the ends of chromosomes
what is the kinetochore?
assembles at each centromere and binds to protein filaments called microtubules - pull sister chromosomes apart
what do telomeres contain?
tandem repeats with G rich sticky tail - forms loop region
what enzyme adds telomeric repeats?
telomerase
how does telomerase extend the ends of chromosomes?
uses reverse transcriptase of own RNA template
what is splicing?
removal of non coding introns from the pre mRNA to generate continuous RNA
what is intergenic DNA?
portion of genome that does not encode proteins or structural RNAs (60% of human genome)
what are regulatory sequences?
regions of DNA that are required to direct and regulate transcription
