exam 4
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72 terms
Terms | Definitions |
|---|---|
 regulation for prokaryotes | DNA --> RNA --> protein --> activated protein |
| transcriptional control bacteria | occurs when regulation proteins affect ability a RNA polymerase to bind to promotor; EFFICIENT because so early |
| translational control bacteria | alter the length of time mRNA survives before it is degraded, affect translational initiation or elongation; make rapid changes |
| post translational control | activated by chemical modification;; addition of phosphate group; most rapid |
| constitutively | some genes are transcribed all the time like enzymes needed for glycolysis |
| enzyme B galactosidase | catalyzes reaction that breaks sugar into glucose (goes directly in glycolytic pathway) and galactose |
| inducer | substrate in reaction that stimulates the expression of the specific gene/s |
| Mutagens | chemicals that damage DNA and increase mutation rates |
| Replica Plating | ... |
| Indicator plates | where mutants with metabolic deficiencies are observed directly (opposite of replica plating) |
| medium | liquid or solid that supports growth |
| Constitutive Mutants | abnormal cells because the produce product all the time |
| lacZ | lactose metabolism mutants that cannot cleave indicator molecule even if lactose is present as an inducer; no b galactosidase (gene for it is defective) |
| lacY | cannot accumulate lactose;no membrane protein (galactosidase permease) to import lactose; gene for it is defective |
| lacI | cannot cleave indicator molecule even if lactose is absent as an inducer; constitutive expression of lacY and lacZ |
| lacI | product all the time |
| lacY | no lactose at all |
| lacZ | no b galactosidase |
| if no lactose | lacI turns off lacZ and lac Y |
| if lactose | transcription of lacZ and lacY is induced |
| positive control | triggers transcription; protein binds to DNA |
| repressor | lacI; transcription inhibitor; Parking brake |
| negative control | shuts down transription |
| Jacob-Monod model | lac operon regulation with lacZ lacY and lacI |
| operator | where repressor binds on the section of DNA |
| Allosteric Regulation | form of control over protein that causes change of shape and activity |
| Catabolite Repression | form of feedback inhibition sometimes called end point or end product inhibition |
| glucose | catabolite; when glucose is abundant, transcription of lac operon is increased |
| CAP | regulatory protein that controls positive control |
| CAP binding site | where CAP binds; jsut upstream from lac promotor |
| cyclic AMP (cAMP) | green light that allows CAP to bind to CAP binding site |
| adenylyl cyclase | enzyme which produces cAMP from ATP |
| extracellular glucose levels high | intracellular cAMP concentrations low |
| extracellular glucose levels low | intracellular cAMP concentrations high |
| E.Coli only activates genes for positive and egative control when? | only when lactose is available and glucose is scarce or absent |
| chromatin reading | DNA wrapped around 8 histones that make up nucleosomes |
| charges of chromatin | DNA-neg; histones-pos |
| chromatin remodeling complexes | multi proteins that reshape chromatin using ATP reactions, to untwist |
| acetylation | positive control of chromatin untwisting |
| methylation | positive or negative control; activation or inactiviation |
| Histone Acetyl Tranferases HATs | enzyme which modifies chromatin by adding acetyl group to histones |
| Histone deacetylases HDACs | turns off transcription and removes acetyl groups that were added by HATs |
| Histone code | precise patterns of modifications made to histones contain info |
| epigenetic inheritance | patterns of inheritance that are not all due to differences in DNA |
| TATA binding protein | next step after chromatin remodeling |
| Enhancer- | the regulatory sequence is very far away from the promoter and is downstream of the promoter rather than upstream |
| • Silencers | regulatory proteins bind here to shut down transcription- thus an element of negative control |
| Regulatory transcription factor | proteins that bind to enhancer, silencer, or promoter- proximal elements, responsible for expression of particular genes |
| Basal transcription factors- | interact with the promoter, must be present for transcription to occur but they do not provide much in the way of regulation, example- TBP |
| o Mediator complex- | role in starting transcription because they create a physical link to the basal and regulatory transcription factors |
| Regulation of mRNA life span, stability, translation, and post-translational modifications | ... |
| spliceosomes | do splicing |
| Alternative splicing | gene expressions are possible because selected exons can be removed from primary transcription along with the introns thus the same primary RNA can yield many matured mRNAs with different combos of exons, controlled by proteins that bind to RNAs in the nucleus and interact with the spliceosomes |
| RNA interference | life span of mRNA is controlled by tiny single- stranded RNA (microRNA) molecules that bind to complementary mRNA sequences so that the mRNA becomes double stranded, then specific proteins degrade the mRNA and prevent it from being translated in a polypeptide |
| post translation | proteins folded by chaperones, modify by adding carbo groups, and cleaving off certain AA and phosphorylation |
| targeted destruction of proteins | ubiquitin added in M phase and is recognized by multi molecular machine called proteasome which cuts into short segments; controls life span |
| eukaryotes | in default state of off from negative control of chromatin structure |
| prokaryotes | in default positive control 'on' because freely accessible promotors |
| bacteria | no splicing; becausae don't code for many only 1:1; opposite for eukaryotes |
| CAP; repressors and other regulatory proteins | not as conplex as eukaryotes at all |
| operons are rare in eukaryotes | because genes are scattered; so prokaryotes much more have coordinated expressions through operons |
| • Proto- oncogenes- | genes that trigger cell growth and division, in normal cells are active only when conditions are appropriate for growth but cancerous cells can regulated them and cause them to stimulate growth at all times, |
| oncogene | promotes cancer development |
| • p53 gene | most often defective in human cancers, codes for a regulatory transcription factor that serves as a master brake for the cell cycle |
| Reverse transcriptase | catalyzes the synthesis of DNA from an RNA template this producing a complementary DNA (cDNA |
| • Plasmid | a small, circular DNA molecule that can clone a gene, researchers realized that they could splice a loose piece of DNA into a plasmid and then insert it into a bacteria where more will be made- cloning vector |
| DNA library | a collection of DNA sequences with vectors, give researchers a way to store info in a cell type that is accessible |
| ddNTP | like dNTPs except lack a hydroxyl group at the 3' carbon, terminates synthesis |
| Single nucleotide polymorphisms (SNPs)- | a site in DNA where some individuals have a different base |
| Carrier testing | looking at the individual's family history and see if they have the allele |
| Prenatal testing | looking at DNA from fetal cells and amplifying them from PCR |
| Adult testing | test for the gene and make lifestyle changes |
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