Study Guides (248,144)
Canada (121,340)
Biology (475)
Midterm

Lecture Material for Test 3.docx

7 Pages
83 Views
Unlock Document

Department
Biology
Course
BIOLOGY 2F03
Professor
Lovaye Kajiura
Semester
Fall

Description
Lecture Material for Test 3 October 13 Template-directed synthesis -similar to DNA but don’t need primer -where you start, you pick -diff component of holoenzyme -sigma locates what you’re interested in -holoenzyme has to move along, binds loosely to DNA -sigma factor helps located promoter -promoter sequence similar to concensus sequence -same holoenzyme with diff sigma factors locate diff genes -follow direction of TATAAT -in virus DNA, genes are overlapped -change of one base can cause many changes in diff proteins -in cell DNA, has a lot of DNA available -change in one base (third base) will not affect much since DNA is redundant -form open complex, let go of sigma factor -core enzyme binds very tightly to DNA -becomes a very processive enzyme -initiation, elongation, termination -2 types of termination -one type forms hairpin, one single strand DNA -has ternary complex will be disrupted by any formation of bulky structure -other type: Rho factor -pulls RNA off complex -transcription in eukaryotes -has 3 RNAP for diff kinds of genes -RNAP II – polymerase that is responsible for making all mRNA -responsible gene -want to be able to control -RNAPs equally complicated -inhibitors -if there are any molecules that go in and bind to complex -don’t need to know too much about this -actinomycin D – not specific, just intercalates and bind tightly to DNA -polymerase won’t be able to find promoter -crystallography gives electron density -gives where atoms are position -need good resolution to see actual atoms -drug designs based on very fundamental diff btw diff processes -antibiotics look for ribosomes of bacteria -inhibit translation in bacteria -since bacterial translation diff enough the human translation -specificity important in terms of drug therapy, toxicity – how unspecific a drug is -therapy for cancer is unspecific -eukaryotes have diff types of promoter -usually related to TATA but not all genes have TATA box -some genes have BRE sequence -at diff regions, has diff concensus sequence -instead of having one single sigma factor, we have a large number of protein called general transcription factors -sigma factor uses in prokaryote system to help identify gene that you want since e.coli doesn’t have a lot of genes -in eukaryotes, have many genes and many diff cell types, need many more combinations how to search through genes -TBP (TATA binding protein) – transcription factor for polymerase II TFII contains 2 proteins: TBP and TAF -binds to minor groove (nonspecific for bases) -eukaryotic system involves many transcription factors Postranscriptional Processing -after making RNA molecules (primary transcript) -needs to be processed before it can be delivered to fxtional molecule -no processing prokaryotes -add on 5’ caps and poly A tails at 3’ in eukaryotes -lengthens lifetime of mRNA -lot of nucleases in cell that digest single strands easily -want to protect both ends -cap for other machinery to look for -mRNA from eukaryotic has many intervening sequence – introns -exons expressed -splice introns out -consensus sequence at exon-intro junction -tranesterification -RNA less stable b/c has 2’ hydroxide -energy of moving almost the same -same gene can give many diff isoforms -diff splicing rxn gives diff molecules from same gene -by removing diff portion of gene (treat parts of intron) get diff products -alternative splicing – variation in processing of RNA molecule -intro can splice itself out from RNA -RNA can form very stable tertiary structures -DNA molecule always has complementary strand; always in duplex -RNA does not have complementary strand, has sequences that are complementary to itself and form many diff unique structures -tRNA when it gets transcribed, a lot of regions removed, some added on -some bases are modified -forms mature RNA after mods -many genes, genes needed are transcribed -locate gene, decided which one to be trancsirbed -initiate, transcription factor comes off -termination sequence (can depend or not on Rho factor) -in eukaryote, no termination sequence or Rho factor -RNA molecule keeps being transcribed until some nuclease cuts it off -don’t need to kno all the splicing processes since they are still being researched October 15 -need telomerase to add to ends of DNA so it does not die upon replication -if telomerase is triggered in every cell, cell would live longer but not healthier -theres a reason they’re not expressed in certain cells -mRNA used to make many copies of proteins according to w.e instruction you have -mRNA starts translation before transcription finishes -occurs in same compartment in prokaryotic cells -in eukaryotic cells, mRNA made in nucleus and translation occurs in cytosol -want to express protein when needed -transcribed DNA when needed by sending out sigma factors -mRNA has to be there only for the needed amt of time -control -the more secondary structures you have on mRNA, the more stable; less susceptible to nucleases -TATAAT on mRNA sequence -where do you start making mRNA -approx 10 base upstream -need to kno amino acids -adaptor molecule: tRNA -folds into clover leaf structure -unique 3d structure -one end recognizes codon, other an holds aa -if we have 2 bases, would have only 16 aa (4 ) -one insertion/deletion will cause frameshift -changing bases not as detrimental -b/c there are 64 codons and only 20 aa - redundancy -64 codon -anticodons pairs
More Less

Related notes for BIOLOGY 2F03

Log In


OR

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.


Submit