New User Special Price Expires in

Let's log you in.

Sign in with Facebook


Don't have a StudySoup account? Create one here!


Create a StudySoup account

Be part of our community, it's free to join!

Sign up with Facebook


Create your account
By creating an account you agree to StudySoup's terms and conditions and privacy policy

Already have a StudySoup account? Login here

BIOL 302 week 2.23-2.25

by: Michaela Sanner

BIOL 302 week 2.23-2.25 BIOL 302

Marketplace > University of South Carolina > Biology > BIOL 302 > BIOL 302 week 2 23 2 25
Michaela Sanner
GPA 3.5

Preview These Notes for FREE

Get a free preview of these Notes, just enter your email below.

Unlock Preview
Unlock Preview

Preview these materials now for free

Why put in your email? Get access to more of this material and other relevant free materials for your school

View Preview

About this Document

These notes cover the material covered in class on the dates 2/23/16 and 2/25/16.
Cell and Molecular Biology
Erin Connolly
Class Notes
25 ?




Popular in Cell and Molecular Biology

Popular in Biology

This 7 page Class Notes was uploaded by Michaela Sanner on Friday February 26, 2016. The Class Notes belongs to BIOL 302 at University of South Carolina taught by Erin Connolly in Spring 2016. Since its upload, it has received 34 views. For similar materials see Cell and Molecular Biology in Biology at University of South Carolina.


Reviews for BIOL 302 week 2.23-2.25


Report this Material


What is Karma?


Karma is the currency of StudySoup.

You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!

Date Created: 02/26/16
2/23/16                 5) TF II H phosphorylates RNA Polymerase II                          ­TF II H has protein kinase                         ­phosphorylation of RNA Polymerase II causes a change in shape (30) ­>  RNA Polymerase II is released from complex and transcription begins                          ­phosphorylation occurs at CTD ( C­terminal domain)                                  ­CTD­ long tail/extension that extends from the body of RNA polymerase II                 6) General transcription factors are released from the DNA and can be recycled  mRNA Processing in Eukaryotes* mRNA processing         mRNA­­> modified chemically­­>then ready for translation Eukaryotes:          ­DNA in nucleus                  ­transcription occurs in nucleus         ­translation in cytosol on ribosomes         ­transcription & translation are separated in space and time                 ­mRNA processing helps to link transcription and translation Prokaryotes:         ­no nucleus; single compartment         ­transcription & translation occur in same compartment         ­translation can begin before transcription of a RNA is complete                 ­**2 processes are linked  Eukaryotic cells: Transcription (nucleus) ­>  primary transcript(nucleus)­>  mRNA processing(nucleus)­> mature transcript(nucleus)­> export of mature transcript from nucleus to cytosol (occurs via nuclear pores) ­>  translation (cytosol on ribosomes)  mRNA processing 3 steps occur to primary transcript (only in eukaryotes occur in nucleus;  only mRNAs so RNA Polymerase II transcripts)         1) mRNA capping         2) polyadenylation         3) splicing                 ­result in mature transcript  RNA Capping: modification of the 5' end of transcript; 5' end is "capped" by the addition of a  special nucleotide          (7­methyl guanosine)          ­cell adds this cap before transcription is complete  **Transcription and RNA Processing are coupled processes          ­phosphorylation of CTD of RNA polymerase II enables RNA Processing                  ­RNA processing enzymes bind to phosphorylated CTD of RNA Polymerase II Polyadenylation: modification to the 3' end of the transcript; 3' is trimmed (at particular  sequence)          ­add series of adenine ribonucleotides at 3' end of transcript         ­series of adenines at 3' end is "poly A tail" only found on eukaryotic mRNAs         ­generally between ~150­250 nucleotides long Functions of mRNA modifications**         ­stabilize the mRNAs         ­aid in export from nucleus         ­used by translation machinery to indicate that a transcript is complete and intact  Splicing:          ­eukaryotic genes are often interrupted by non­coding sequences                  ­Interon­a region of a eukaryotic gene that does not** code for protein, but that is  part of the primary transcript                          **interons are excised from RNA by splicing to generate mature transcript                  ­Exons­ segments of eukaryotic genes that are part of both the primary and mature transcript and do* code for proteins How does the cell know which parts to splice out/remove? **special sequences in mRNA recognized by enzymes that perform splicing** Interon coding:         R=A or G         Y=C or U         N=A, G, C, or U (non­specific position) Splicing Requirements**         ­3 special sequences in mRNA         ­enzymes that recognize the special sequences (enzyme complexed called snRNPs  "snurps")         ­snRNPs­ small nuclear ribonucleoprotein particles                 ­are splicing enzymes                  ­form the core of spliceosome          ­spliceosome ­ large assembly of RNA and protein that performs RNA splicing  Splicing mechanism­Simplified          1) branch point A in interon attacks the 5' splicing site/junction and cuts the sugar  phosphate backbone at the junction          2) 5' end of interon is covalently linked to the 2'OH of the ribose of the branch point A  (formation of a lariat)          3) the free 3'OH of the 1st exon then reacts with the beginning of 2nd exon, joining the  2 Exons together, and releasing the interon  Benefits of Splicing*         ­alternative splicing                  ~60% human genes are spliced                  ­production of different proteins from the same RNA transcript by splicing it in  different ways          **allows eukaryotic organisms to increase the coding potential of their genomes** 2/25/16 mRNA Export from nucleus to cytosol:         ­mRNAs leave nucleus via nuclear pore complex         ­requires proteins:                 ­poly A binding protein                 ­cap binding protein             } recognize chemical modifications (Poly A, cap, exon)                 ­exon junction complex                 ­nuclear transport receptor  mRNA turnover / RNA degradation ­­> RNA stability          ­mRNAs are degraded at different rates ~10min­>~12 hours          ­stability is controlled by signals (sequences within RNA) within the RNA itself          ­often UTRs are important for stability of transcript                   UTR­Untranslated region  Translation:         ­decoding the information in mRNA to produce polymers constructed of amino acids                 mRNA­­> protein         4 nucleotide (RNA­ 4 letter alphabet)         20 amino acids (proteins­ 20 letter alphabet)         ­an mRNA is decoded in sets of 3 nucleotides (codon)                  ­governed by genetic code : sets of rules that speciify correspondence between  nucleotide triplets (codon) and amino acids in proteins          ­64 combinations of triplets not equal to 20 amino acids                         **genetic code is redundant** meaning can be more than one codon per  amino acid         ­codon­sequence of nucleotides in a DNA or RNA that represents the instructions for  incorporation of a particular amino acid into a polypeptide chain          ­amino acids are coded by between 1 and 6 different codons          ­there are 3 STOP codons (causes gene termination) (code for no amino acid)                 ­­> 61 codons that code for amino acids          ­one start codon­AUG­­>methionine          ­triplets that code for the same amino acid tend to have the same nucleotides @  position 1 and 2 and tend to differ at position 3                  ­Ex: Glycine                          1                2                3                         G                G                A                         G                G                C                         G                G                G                         G                G                U                         ­­                ­­                ­­                         G                G                N­"wobble" @ 3rd position Reading Frame: one of 3 possible ways/methods to "read" a nucleotide sequence in RNA as  sets of non­overlapping triplets  RNA 5' AUG. CCG. UUU.  GCU.  AUA.    AAA.   CUG.   3'     Met    Pro    Phe     Ala     Ile         Lys      Leu                     ­first reading frame         Cys     Arg      Leu     Glu    Stop           ­second reading frame (decode starting at 2nd  nt.)                 Ala      Val     Cys      Tur        Lys        Thr        ­third reading frame(start @ 3rd nt.) What is required for translation?**         ­mRNA         ­2 types of adaptor molecules                  1) tRNAs                 2) amino acyl tRNA synthetases  tRNAs         ­adaptors that recognize both the RNA triplet in the mRNA and the correct  corresponding amino acid                  ­~80 nucleotides long                 ­fold up into 3­D structures called "clover leaf"                  ­anticodon loop ­ base­pairs with a complementary codon in mRNA                  ­3' end of tRNA                          ­covalent attachment of amino acid          61 codons not equal to 20 amino acids                 ­some tRNAs can base­pair with more than 1 codon in RNA                  ­some tRNAs can tolerate a mismatch at the 3rd position                  ­# of tRNAs dependent on species Amino acyl tRNA synthetases         ­enzymes that recognize and attach the correct amino acid to a given tRNA                  tRNAs minus amino acid "uncharged" tRNAs                 tRNAs plus amino acid "charged" tRNAs  Translation         ­mRNA         ­tRNA + amino acyl tRNA synthetases         ­ribosomes                 ­large protein + RNA complexes                  ­decodes mRNA and synthesizes protein  Ribosomes­ have 2 subunits ( higher order)         ­large subunit                 ­49 proteins and 3 RNAs (rRNAs)         ­small subunit                 ­33 proteins and 1 RNA (rRNA)          ­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­ Total:         82 protein and 4 RNA (rRNAs) Ribosomes function: ­small subunit ­ matches tRNAs to codons in a mRNA  ­large subunit ­ catalyze formation of peptide bonds  Ribosome Binding Site         1) mRNA binding site­small subunit         2) A site ­ amino acyl tRNA ­ "charged" tRNAs enter ribosome         3) P Site ­ peptidge tRNA ­ peptide bonds made         4) E site ­ exit ­"uncharged" tRNAs exit complex here                  2­4 are tRNA binding sites: only 2 tRNA binding sites may be occupied at one time Translation­ 3 Stages         1) Initiation ­not covered       **  2) Elongation         3) Termination ­not covered Steps of translation elongation          ­start with a chain of  3 amino acids                  ­>addition of amino acid #4 to pre existing chain    1) amino acyl tRNA binds in A site (carrying amino acid #4)    2)    3)    4)


Buy Material

Are you sure you want to buy this material for

25 Karma

Buy Material

BOOM! Enjoy Your Free Notes!

We've added these Notes to your profile, click here to view them now.


You're already Subscribed!

Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'

Why people love StudySoup

Steve Martinelli UC Los Angeles

"There's no way I would have passed my Organic Chemistry class this semester without the notes and study guides I got from StudySoup."

Jennifer McGill UCSF Med School

"Selling my MCAT study guides and notes has been a great source of side revenue while I'm in school. Some months I'm making over $500! Plus, it makes me happy knowing that I'm helping future med students with their MCAT."

Jim McGreen Ohio University

"Knowing I can count on the Elite Notetaker in my class allows me to focus on what the professor is saying instead of just scribbling notes the whole time and falling behind."

Parker Thompson 500 Startups

"It's a great way for students to improve their educational experience and it seemed like a product that everybody wants, so all the people participating are winning."

Become an Elite Notetaker and start selling your notes online!

Refund Policy


All subscriptions to StudySoup are paid in full at the time of subscribing. To change your credit card information or to cancel your subscription, go to "Edit Settings". All credit card information will be available there. If you should decide to cancel your subscription, it will continue to be valid until the next payment period, as all payments for the current period were made in advance. For special circumstances, please email


StudySoup has more than 1 million course-specific study resources to help students study smarter. If you’re having trouble finding what you’re looking for, our customer support team can help you find what you need! Feel free to contact them here:

Recurring Subscriptions: If you have canceled your recurring subscription on the day of renewal and have not downloaded any documents, you may request a refund by submitting an email to

Satisfaction Guarantee: If you’re not satisfied with your subscription, you can contact us for further help. Contact must be made within 3 business days of your subscription purchase and your refund request will be subject for review.

Please Note: Refunds can never be provided more than 30 days after the initial purchase date regardless of your activity on the site.