Unit 6 - DNA Replication, Transciption, Translation Flashcards
Topoisomerase
Uncoils the DNA
DNA Helicase
Breaks the H-bonds
DNA Polymerase III
adds nucleoside triphosphates
DNA Polymerase I
replaces RNA primers with DNA
Ligase
cleanse up and joins the okazaki fragments
Exonuclease
proofreader
Endonuclease
cleaves the bad parts
Transcription in Eukaryotes
Initiation: promoter region (TATA box); transcription factors help RNA polymerase bind
Elongation occurs
Termination: Polyadenylation Signal Sequence (AAUAAA) releases the pre-mRNA; post-transcription modifications (5’cap, poly-A tail, splicing [splicisomes; alternative splicing increases variation])
Transcription in Prokaryotes
Initiation: RNA polymerase directly binds to the promoter region
Elongation: translation happens simultaneously
Termination: termination sequence; no modifications
Termination in Eukaryotes
Initiation: universal start codon AUG
Elongation: tRNA brings specific animo acids based off the codons that match with the anticodon on the tRNA; peptide bonds form to make a polypeptide chain; translocation moving from right to left (EPA)
Termination: stop codon at A site
Acetylation
loosens/opens up the DNA; increases transcription; on HISTONES
Methylation
closes/condenses DNA; reduces/stops transcription; on nucleotide/DNA
Epigenetics
external to DNA that will regulate gene expression (heritable)
Retrovirus
transcription/translation from RNA to DNA
DNA point mutations/substitution mutations
Silent: no impact
Missense: depends on the R-group and if the function is still the same there will be no impact
Nonsense: nonfunctional protein is made
Frameshift
nucleotide base is added/deleted which will case all RNA after to shift
could code for accidental stop codon
after the shift point all codons could be different
Eukaryotic Enhancers
Enhancers on a DNA sequence will activate transcription factors after folding over due to a bending protein; transcription factors can be activators or repressors
Help regulate gene expression
ex: Cytoplasmic Determinants and Induction
HOX Genes
different sports for different genes
different body parts/characteristics will show depending on where it’s turned on
TRP Operon (tryptophan)
repressive–normally ON; a substance causes it to be stopped
build up of tryptophan (in this case is also a corepressor which is an enzyme that is produced that also turns it off) will bind to the operator as a repressor (operator inhibits the operon) and the gene will not be produced
when tryptophan is removed, the operon will be able to function again
LAC Operon (Lactose)
inducible–normally OFF; a substance causes it to start
takes advantage of lactose when it shows up for ATP
when there is lactose in the environment, an inducer will attach to the operator and the repressor is released which will allow the rest of it to make genes that break down the lactose and use it
Lytic Cycle – bacteriophage
- insert virus DNA into bacteria
- break host DNA
- reproduce
- cell lysis
- infect other bacteria
Lysogenic
viral DNA – replicated with binary fission
Transformation
- bacteria dies and the DNA is released into the environment
- other bacteria uptake the naked DNA to change the geno/phenotype
Transduction
cell to new, bacteria to bacteria
cell breaks and sends new DNA (virus) out
can also be bacteria DNA
Conjugation
temporary bridge; passing plasmid
Transposon
section of DNA (transposon) can be put into different section
Restriction enzyme
recognize specific sequences on DNA (restriction sites)
DNA Cloning
- cuts parts – corresponding/complementary sticky ends
- ligase binds phosphodiester linkage
- bacteria takes up and transforms (makes more)
- scientists add antibody resistance on plasmid; all that’s left will be resistant plasmids (success)
Gel Electrophoresis
cute DNA with restrictors
DNA = negative charge (will separate)
DNA Ladder: # of bases
top - large - negative
bottom - small - positive
Polymerase chain reaction
- denaturation: add head to the separate strands
- annealing: cool down, add primers
- DNA synthesis (warmer) start
for electrophoresis and diagnostics
