Microbial Genetics Ch. 1-4
Terms
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copy deck
- Polymerization Reaction Step 1?
- RNA and DNA first bind making a closed complex
- Polymerization RXN step 2?
- DNA strands pull apart to make an open complex
- Polymerization RXN after open complex?
- Ribonucleoside triphosphate bonds to template at start site.
- Polmerization RXN step after binding at start site?
- RNA polymerase catalyzes the reaction in which the alpha phosphate of the second nucleotide joins w/the 3' hydroxyl of the first nucleotide.
- Polymerization RXN after polymerase catalysis and before the transcription bubble forms?
- The RNA polymerase holoenzyme loses or releases its sigma factor.
- Polymerization RXN after sigma factor is released.
- The transcription bubble of DNA-RNA hbrid forms. It is about 18 bases long and holds the RNA polymerase.
- Last step of Polymerization RXN, aftr the DNA-RNA hybrid forms?
- Antiparallel complementary copy (transcript) is made on one strand of dna in a particular.
- 1 Cause of Pausing- helped by attenuation.
- Hairpins cause the 3' end of the RNA to be displaced from the active center.
- 1 Cause of Pausing- occurs where there might be a string of U's.
- RNA Bactracking- where RNA polymerase is weak ( because U is weaker than C...)
- Ribosome
-
3 different RNA
20 different Amino Acids
enormous enzyme that polymerizes specific amino acids into polypeptide chains w/mRNA as a guide. - Whole Unit of RNA
- 70S
- 30 S
- 21 different proteins initiated translation by binding to mRNA and then to the second part of RNA.
- 50 S
- 31 different proteins- forms peptide bonds and translocates the nucleic acid.
- DNA strand that is copied
- transcribed strand
- DNA strand that isn't copied
- coding strand
- This attaches methionine to the tRNA
- aminoacultransferase
- this adds a formy group to form the fMet-tRNAfmet.
- transformylase enzyme
- this removes the n-terminal methionine
- the enzyme methionine aminopeptidase
- a 5-10 nucleotide set on 5' ide that define a TIR. are complementary to short sequnces w/in regions of 16S.
- Shine-Dalgarno sequence
- Factor-independent termination
- 2 sequences- inverted repeat
- Factor-dependent termination
- pho termination: short string of amino's; RNA forms a hairpin which destroys the DNA-RNA hybrid.
- Translational Fusions
- 2 coding sequences are cloned so they are translated into the tsame frame w/no nonsense codons b/w them. this makes a fuision protein w/either amino terminus or carboxyl terminus.
- RNA precursors
- sugar ribose at 2nd carbon, uracil, bases 5'-3', phosphates 3'-5'.
- pseudoknots
- unpaired region pairs w/another in hairpin to form a knot: held weakly together by H bonds.
- secondary structure of RNA
- paired strands are antiparallel and stiff.
- tertiary structure of RNA
- the RNA is stiffer, folds back on self, has pseudoknots.
- polycistronic mRNA
- more than one TIR to allow simulataneous translation of more than one sequence of mRNA.
- 3' untranslated region
- region between the last codon and the 3' end
- ambiguity in translation
- specify differently at certain locations of mRNA (UGA is example).
- Nonsense codons
- VAA, VAG, UGA: don't encode amino acids, they terminate.
- spontaneous mutagenesis
- occur normally as mistakes in DNA replication; rarer but less likely to contain more than one kind of mutation; can be base pair changes, duplications, insertions, deletions, frameshifts, etc.
- induced mutagenesis
- treating the ells w/some chemicals or with some types of irradation by iducing. can get only one particular type of muatation.
- genotype
- geneticcomposition, lacZ
- phenotype
- observable or detectable property, LacZ
- Haploid
- single set of genes- 1 copy
- Alleles
- different or alternative forms of a particular gene proA58, pro A79
- proA-
- mutant (doesn't have function), absence of phenoytpe
- homozygous
- organism with two identical alleles
- heterozygous
- organism with two different alleles.
- wild type strain
-
arbitrarily chosen strain
isogenic sequence - mutant strain
- any changes or mutations in DNA w/respect to wild-type strain.