4. Protein_Study_Guide-1.pptx - Unit 4 Protein Part 1 RNA Synthesis Transcription and RNA Processing Concepts for Study The central dogma

4. Protein_Study_Guide-1.pptx - Unit 4 Protein Part 1 RNA...

This preview shows page 1 - 14 out of 134 pages.

Unit 4. Protein
Image of page 1

Subscribe to view the full document.

Part 1: RNA Synthesis Transcription and RNA Processing
Image of page 2
Concepts for Study The central dogma: DNA->RNA->protein, referred to as the “flow of information” in Biology. Transcription How RNA polymerase, guided by base pairing, synthesizes a single-stranded mRNA copy of a gene’s DNA template How other RNA’s for the cell are made In eukaryotes, there is complexity in the initiation steps, and there are significant processing steps for mRNA, required for mRNA to be exported from the nucleus. Highlight significant differences in gene expression between bacteria, archaea and eukaryotes
Image of page 3

Subscribe to view the full document.

DNA is the genetic material, but how does this get translated to protein? DNA is in the nucleus for Eukaryotes, but protein synthesis occurs in the cytosol, deduced from radioactive tagging of amino acids Messenger RNAs were discovered, molecules for transporting genetic information: An intermediate molecule made in nucleus that could travel out Remember, Bacteria and Archaea do not have a nuclear barrier, in fact RNA is translated as it is being produced (Transcription and Translation are coupled)
Image of page 4
Central Dogma Cricked coined this term since it embodies the essence of information transfer in biology. Transcription/translation=the expression of genes.
Image of page 5

Subscribe to view the full document.

Keeping the terms straight Transcription in the English language is to make a copy (in the same language). In Biology, DNA->RNA are both in nucleotide language. Translation is to change languages. In Biology, RNA-> protein involves changing languages, from nucleotide to amino acid. Think of Indiana Jones in the pyramid as an analogy to RNA polymerase in the nucleus. (If you missed this class, you are really confused right now)
Image of page 6
Strand Orientation DNA is double stranded, yes? Then which strand designated the gene code that will dictate protein? RNA is a single stranded copy of which strand? The “ template ” strand is the one designated as the strand to by copied The other DNA strand is a mimic of the RNA copy, the “ RNA- like ” strand. Draw this for yourself starting with DNA below, making an mRNA copy, and designating which strand of DNA thus looks like the mRNA sequence. 5’-AATTGGCGCGTGAAATCG-3’
Image of page 7

Subscribe to view the full document.

One strand of DNA is a template The other is an RNA-like strand
Image of page 8
Note also, 5’ to 3’ direction of mRNA corresponds to N-terminal- to-C-terminal direction of polypeptide
Image of page 9

Subscribe to view the full document.

RNA polymerase The enzyme that makes the RNA copy is oriented by sequences in the DNA, upstream of the gene. RNA Pol binds on to the DNA in a specific way, ready to move in a direction that chooses which strand is the template strand. THUS…The direction of the polymerase and the code that is copied then is dictated by small DNA sequence signals (e.g. promoter elements) More about this in a minute…
Image of page 10
RNA Structure Reminder: Structure is the same as DNA except: Now we have a 2’ OH as well as a 3’ OH Uracil will replace Thymine RNA is “single stranded” However, RNA has immense secondary structure resulting from internal base pairing
Image of page 11

Subscribe to view the full document.

Secondary structure with stem loops and internal base pairing can be very complex. The overall 3-D shape is critical to the function of each RNA
Image of page 12
More than Three Classes of RNA
Image of page 13

Subscribe to view the full document.

Image of page 14

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern

Ask Expert Tutors You can ask 0 bonus questions You can ask 0 questions (0 expire soon) You can ask 0 questions (will expire )
Answers in as fast as 15 minutes