Biochemistry 2280A Lecture Notes - Lecture 6: Nuclear Membrane, Telomerase, Somatic Cell
11 May 2020
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Nucleus : only in eukaryotes, store dna, enclosed in a nuclear envelope which is porous, allowing entry and exit, nucleolus function to make ribosomes, each somatic cell nucleus has 2 copies of each autosome. Heterochromatin = dark, dense, less transcriptionally active (sometimes have no genes) Euchromatin = light, loose, more active genes are being made; causes a banding pattern on the chromosomes. Origins of replication: where dna duplication originates, located within dna molecules and create 2 replication forks that move away from one another. Prokaryotes e. coli: single circular chromosomal dna molecule 1 origin of replication, don"t have a nucleus dna is floating within the cell where it is, is called a nucleoid, array of 4289 protein-coding genes. Have fewer isoforms due to having no introns: replication still have a leading and lagging strand, and semi-conservative process, human genome has 700 x more dna than an e. coli genome but only 5x more genes.
