Starting fresh
Differences between Genenotype and phenotype
Gene= actual gene conformation
Pheno= he expression of the gene.
PP or Pp could have the same phenotype, yet they have different genotypes.
Initiation
•In bacteria, the small subunit of the ribosome binds fMet-tRNA (Met-tRNA in archaea and eukaryotes) and then binds the mRNA at a special initiator codon (AUG); then the large subunit of the ribosome binds
Mutations
stable, heritable change in the genomic nucleotide sequence; this can be a single base change (point mutation), changes of several bases, or larger insertions, deletions, inversions, duplications, and translocations
•F+ ´ F– mating
•F plasmid moves from the donor (F+) to a recipient (F–) while being replicated
modulon
•more complex and has a common regulatory protein that controls an operon network, individual operons are controlled separately as well
List the order of event from DNA to protein
DNA coding strand
Template trands serves to make RNA by Transciption mRNA gets modified and leaves the nucleus.
mRNA goes to translation in the cytoplasm to for a polypeptide
polypedtide becomes a protein.
Elongation
Elongation involves the sequential addition of amino acids to the growing polypeptide chain
The ribosome has three sites for binding tRNA molecules: peptidyl site (P site), aminoacyl site (A site), and exit site (E site)
The ribosomal enzyme peptidyl transferase catalyzes the formation of the peptide bonds between the amino acid (or growing peptide chain) held by the tRNA in the P site and the amino acid held by the tRNA in the A site;
Transition
Same group
Certical gene Transfer
transmission of genes from parents to offspring)
lac repressor protein is inhibited by
allolactose
Code degeneracy
many amino acids are encoded by more than one codon
Transduction
•is a consequence of mistakes that naturally occur with assembly of new bacteriophage in a microbial host cell
–Two basic types
1.Generalized: any DNA transferred
2.Specialized: Specific DNA transferred
Transversion
exchaning different types of bases from different category (purines vs pyrimidine)
Horizontal (or lateral) gene transfer
moves genes from one mature, independent organism to another
glucose + lactose
Lack of CAP = No transcription
Wobble
describes the somewhat loose base pairing of a tRNA anticodon to the mRNA codon; wobble eliminates the need for a unique tRNA for each codon because the first two positions are sufficient to establish hydrogen bonding between the mRNA and the aminoacyl-tRNAs
secretion system in Gram +
secrete proteins across the plasma membrane using the Sec-dependent pathway
Spontaneous Mutations (3)
1. Errors in replication (no external Factors)
2. tautomeric shifts
3. Lesions in the structure of DNA
IS elements
•contain genes only for those enzymes required for transposition (e.g., transposase); they are bound on both ends by inverted terminal repeat sequences
No glucose no lactose
Transcription is stopped by repressor
Central Dogma
the process by which the instructions in DNA are converted into a functional product
Gram (-) secretion pathway or system
SEC
TAT
Types I-V
Induced mutations (3)
1. Base analogs
2. Specific mispairing
3. Intercalating agents
Differences between Conjugation-Transformation-Transduction.
•Conjugation is direct transfer from donor bacterium to recipient while the two are temporarily in physical contact
•Transformation is transfer of a naked DNA molecule
•Transduction is transfer mediated by a bacteriophage
Explain the Lac Operon
Based of Proffesor Consideration.