Cell Biol Chapter 10 outline
Nucleus, Organization of DNA, Transcription
I. Nucleus
A) features
- size
- double membrane
- pores
- nuclear lamina
- nucleoplasm
- nucleolus
II. DNA organization in eukaryotes
A) chromosomes
1) karyotype
2) chromosome number and amount of DNA
B) structure
1) histones
2) organization
a) double helix
b) nucleosomes
c) solenoid
d) chromatin
e) chromosomes
3) accessibility of DNA/modification of DNA (compare heterochromatin and euchromatin)
a) phosphorylation of histone H1
b) acetylation and methylation
c) high mobility group proteins (HMG)
III. Transcription
A) RNA polymerases
B) promoter regions/transcriptional factors
1) prokaryote
2) eukaryote
IV. Processing of hnRNA (pre-mRNA)
A) removal of introns
1) snRNPs
2) spliceosome
B) 5' cap
C) 3' poly-A tail
V. Control of gene expression
A) control in prokaryotes
1) anabolic pathways
2) catabolic pathways
3) operons and promoter regions
a) promoter regions
b) lac operon - control
_I_________P_____O_____Z______Y_______A__________
c) catabolite repression or glucose effect
B) control in eukaryotes
1) amount of DNA (C value paradox)
a) unique vs. repetitive DNA
b) reassociation kinetics
c) Cot curves
d) classes of repeated DNA sequences
2) levels of control of gene expression
a) genomic control
- DNA lost
- Amplification of DNA
b) transcriptional control
- chromatin structure (accessibility of DNA)
- premature termination
- gene activation – heat shock genes/hormones - steroids, hormone response elements
- polypeptides
- primary vs. secondary responses
c) differential processing of mRNA
d) cytoplasmic control mechanisms
- mRNA half life
- rate of translation
e) posttranslational control
- RNA splicing
- mRNA half life
- antisense RNA
- rate of translation
- protein half life