Ch. 15 study guide
Antibiotic resistance - resistance plasmid, passed down
Understand the operon model and what all the parts do. (this is a large portion of the test)
Operator - controls access of RNA Poly to genes; downstream end of promoter (drawbridge)
Promoter - where RNA poly attaches (all genes of a pathway controlled by one promoter); 1 mRNA
produces all genes
Genes of the operon - stretch of DNA
Repressor - switches off operons (when active, inhibits operon… blocking transcription &
translation)
Corepressor - helps repressor
Regulatory Gene - produces repressor (protein) when binds to operator
Know the differences between the two types of operons (inducible or repressible)
Repressible - on but can be off; anabolic (builds), repressor is inactive, molecule built is corepressor
which activates repressor and turns off gene (trp operon)
Inducible - off but can be activated; catabolic (breaks down), repressor active but inducer
(substrate, starting molecule) makes it inactive, so gene is expressed (Lac operon); always turned on
= ribosomal gene
Know how prokaryotes can increase their genetic diversity.
Bacterial chromosome - binary fission, little genetic variation
-transformation: on purpose, foreign DNA is incorporated in genome; what you get is random
-transduction: random, phages (virus) carries bacterial genes from one host -> another; accidental
(capsid packing)
-conjucation & plasmids: purposeful and direct, horizontal gene transfer (allows bacteria to use
gene, one way), F factor needed (bonus DNA)
mutation = #1, random
What are the ways prokaryotes can regulate gene expression.
Feedback inhibition = tuning metabolism to environment
Operon Model = regulating genes that code enzymes
Eukaryotic gene expression
-all cells have same genes (hair in stomach), but depends on packaging (Bacteria does not)
-differential gene expression = diff. cell types
Tightly packed DNA = reduces gene expression: DNA Methylation (adding methyl groups)
Less tightly packed = encourages transcription: Histone Acetylation (adding acetyl group to
histone)
Transcription Initiation:
-Complex enhances gene expression
-enhancer region = DNA upstream from promoter that controls initiation (by activators)
-DNA bends over so initiation can begin
RNA:
Micro-RNAs (miRNAS) & small interfering RNA (siRNA) - prevents translation
Zygotes: cell division = more cells, cell differentiation = cell types, morpheogenesis = body plan
-we get bigger from cell growth, NOT cell division
Controls of differentiation & morphegenesis:
cystoplasmic determinant = uneven distribution, drives development
cell-cell signals = neighboring cells influence differentiation
Antibiotic resistance - resistance plasmid, passed down
Understand the operon model and what all the parts do. (this is a large portion of the test)
Operator - controls access of RNA Poly to genes; downstream end of promoter (drawbridge)
Promoter - where RNA poly attaches (all genes of a pathway controlled by one promoter); 1 mRNA
produces all genes
Genes of the operon - stretch of DNA
Repressor - switches off operons (when active, inhibits operon… blocking transcription &
translation)
Corepressor - helps repressor
Regulatory Gene - produces repressor (protein) when binds to operator
Know the differences between the two types of operons (inducible or repressible)
Repressible - on but can be off; anabolic (builds), repressor is inactive, molecule built is corepressor
which activates repressor and turns off gene (trp operon)
Inducible - off but can be activated; catabolic (breaks down), repressor active but inducer
(substrate, starting molecule) makes it inactive, so gene is expressed (Lac operon); always turned on
= ribosomal gene
Know how prokaryotes can increase their genetic diversity.
Bacterial chromosome - binary fission, little genetic variation
-transformation: on purpose, foreign DNA is incorporated in genome; what you get is random
-transduction: random, phages (virus) carries bacterial genes from one host -> another; accidental
(capsid packing)
-conjucation & plasmids: purposeful and direct, horizontal gene transfer (allows bacteria to use
gene, one way), F factor needed (bonus DNA)
mutation = #1, random
What are the ways prokaryotes can regulate gene expression.
Feedback inhibition = tuning metabolism to environment
Operon Model = regulating genes that code enzymes
Eukaryotic gene expression
-all cells have same genes (hair in stomach), but depends on packaging (Bacteria does not)
-differential gene expression = diff. cell types
Tightly packed DNA = reduces gene expression: DNA Methylation (adding methyl groups)
Less tightly packed = encourages transcription: Histone Acetylation (adding acetyl group to
histone)
Transcription Initiation:
-Complex enhances gene expression
-enhancer region = DNA upstream from promoter that controls initiation (by activators)
-DNA bends over so initiation can begin
RNA:
Micro-RNAs (miRNAS) & small interfering RNA (siRNA) - prevents translation
Zygotes: cell division = more cells, cell differentiation = cell types, morpheogenesis = body plan
-we get bigger from cell growth, NOT cell division
Controls of differentiation & morphegenesis:
cystoplasmic determinant = uneven distribution, drives development
cell-cell signals = neighboring cells influence differentiation
