BIO130H1 Lecture 6: Packaging of Nucleosomes & DNA Replication
25 Jan 2019
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Packaging of nucleosomes: cohesion is involved in forming chromatin loops, loops may be attached to a nuclear scaffold to enable increased compaction. Euchromatin: relatively non-condensed chromatin, regions of interphase chromosomes where genes tend to be expressed. It"s reversible going from euchromatin and heterochromatin: very dynamic. Note: chromatin is remodelled during transcription to alter access to dna. Transcription factories: areas of the nucleus which are very favourable for transcription, chromatin can be remodelled so it can loop out into the middle. Two daughter cells contain one parental strand and one new strand. It takes about 40min to replicate genome: multiple, eukaryotes, genomes are much bigger and therefore we start replication at more than one place. Replication forks: asymmetrical, leading strand replicated continuously, lagging strand replicated discontinuously, lagging strand is fragmented due to direction of replication, fragments on lagging strand are called okazaki fragments.
