Exam Flashcards
(13 cards)
Transcription Regulation
Transcription factors bind to promoter regions to activate or repress gene transcription
Epigenetic mods like DNA methylation and histone acetylation affect chromatin structure and accessibility
Post Transcription
After mRNA is synthesisted before transcription
Alt splicing, one gene can make many proteins
mRNA editing, can alter codons and affect resulting protein
mRNA stability for transport and protein productionT
Translational
Controls efficiency and frequency of translation
Regulatory proteins and mRNAs can bind to mRNA and prevent ribosome binding
Some conditions can decrease translation
Post translational
Protein folding to functional structure.
Origin of luciferase
As an antioxidant defence against rising oxygen levels due to photosynthetic cyanobacteria.
Different chemical structures and unrelated luciferases suggest independent evo events, across organism groups.
Strong selective pressure in the deep sea may have driven evolution for comm, predation and camo.
Some marine animals rely on symbiotic biolum bacteria, coevolutionary origin of the trait.
High density of bacteria
Secrete autoinducer
AHL accumulates in env and re-enters cells
AHL binds LuxR, forming active complex
LuxR, autoinducer complex binds DNA promoter of lux operon
Transcription of lux operon, luciferase and substrate produced.
Few bacteria
Few autoinducers secreted.
AHL diffuses away, no accumulation
LuxR protein is inactive
Lux operon is not transcribed
No luciferase, no biolumin
RFLP, Sample collection
Collect algal tissue, lyse sample using chemical buffers or mechanical disruption
Restriction enzyme digestion and PCR
Extracted DNA incubated w/ 1 or more restriction endonucleases.
They cut the DNA at recognisable palindromic sequences, generating a mixture of DNA fragments of various lengths.
Resulting fragment patterns defend on DNA sequence of organism.
PCR
Gel electro
Digested DNA landed into agarose gel and electrophoresised
Fragments separated by size, w/ smaller fragments migrating futher.
Creates, bonding pattern, basis for fingerprint
Southern Blotting
DNA bands transferred from gel to membrane.
A labelled DNA probe that binds to specific sequences is applied.
Probe hybridises only to comp seqs, increase specificity and clarity of fingerprint.
Detection
After washing away excess probe, membrane is exposed to X-ray film or imaged using a fluorescent scanner
Result in a stable DNA fingerprint image, showing a distinct pattern unique to organism
Xray crystallography
Determine 3D structure
Solubilised protein
Vapour diffision
X-ray diffraction
Electrong density map
3D structure
