Cell Biology Lecture 16 notes Chapter 8 p.336-356 Cell Nucleus

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Nuclear pores: critical to import of nuclear molecules

Compartmentalization, so transcription and translation not simultaneous

RNA processing

Human DNA= 6 billion base pairs for whole diploid genome

DNA-based computer memory? 10¹⁵ bytes/ml.?

Chromosome= centromere, 2 telomeres, origins of replication (repl. bubbles)

Telomerase and end replication problem (recall: Okazaki RNA primer chewed out)

YAC = million base pairs cloned. HAC now available

<60,000 essential proteins.

"Each region of the DNA helix that produces a functional RNA molecule constitutes a gene"

Paul Berg bets a case of wine. Small % of DNA codes for proteins.

Procaryotes = "wall to wall exons"

H1 and nucleosomal (highly conserved) histones 2 X each H2A, H2B, H3, H4

Acetylation of lysine (lysine, arginine, histidine = + charged) DNA = - charged phosphates

"Major groove" often binds regulatory proteins. "Minor groove" (AT-rich) sticks to histones

Many nucleosomes = "solenoid". H1 involved in nucleosome packing

Decondensed chromatin = more active (puffs); condensed = inactive Heterochromatin; Barr bodies from Lyonization

Polytene chromosomes of Drosophila salivary glands

"Banding" and hormonal exposure

Chromosomal painting

Model of chromatin packing