Title: Ch 15 - .Gene Regulation
1Ch 15 - .Gene Regulation
- Prokaryote Regulation
- Operon not found in eukaryotes
- Regulator gene codes for repressor. Active
repressor binds to operon - Promoter where RNA polymerase attaches
22 types of regulators
- Repressible operon
- 1 always on repressor cannot bind,
therefore RNA polymerase can attach and protein
is made. - Ex. Trp operon
- -To turn off the protein product binds to
repressor repressor can bind transcription
ceases
3Inducible Operon
- 2 always off repressor can always bind
therefore RNA polymerase cannot attach no
protein produced - Ex. Lac operon
4Presence of molecule (inducer) turns on
transcription by binding to lac repressor to
disable binding.
5Eukaryotic Regulation
- allows differential protein expression
dependent on specialized function of cell. - 5 ways 3 within the nucleus 2 in the
cytoplasm
6- 1 chromatin structure packaging makes RNA
epigenetic polymerase binding impossible
cancer results when mutations occur in
transcriptional factor genes.
72 Transcriptional control transcription
factors- proteins that initiate RNA pol. binding
once a gene is unpackaged it will be transcribed.
(transposons shut down genes by interrupting
code, gene jumping, also encourages mutations)
83 posttranscriptional control-mRNA processing
excising introns
94 - translational control poly a tail
protects mRNA from being degraded allows for
translation
10(No Transcript)
115 - Posttranslational control modification of
a protein after synthesis determines biological
activity.
12Chromatin Structure
- DNA wrapped around 8 histones
- DNA histone nucleosomes
- Highly condensed heterochromatin inactive,
methyl groups - Loosely condensed euchromatin active have
attached acetyl group. DNA can be methylated
not expressed can be inherited that way
13KINASES
- Proteins that dephosphorylate to signal protein
expressions in membrane to nucleus regulatory
pathway
14TRANSPOSONS
- Jumping genes of repetitive sequence that
interrupt gene expression
15GENETIC MUTATIONS- good, bad, non effective
- 1-germline ? passed on
- 2- somatic ? not passed on ? cancer
16MUTATIONS causes- spontaneous, environ.
mutagens, inherited0
- Point Mutations- Change a single base? change
codon - Frame shift mutations- deletion or addition
result in a completely new amino acid sequence. - Mutations in proto-oncogenes or tumor suppressor
?cancer
17Study Questions
- What part of mRNA sections are spliced together
into the finished mRNA molecules? - What are 4 potential control mechanisms for
regulation of gene expression in eukaryotic
organisms? - What is the correct order of protein synthesis?
18Study Questions
- What is the role of DNA in controlling cellular
activity? - What word describes the attachment of groups of
particular amino acids of specific proteins to
nucleosomes as thought to be an important control
mechanism for gene expression? - Define the term gene
19Study Questions
- The expression of genes can be controlled at what
4 stages of protein synthesis?