3.1.2 + 3.2.1

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Author:
efrain12
ID:
207459
Filename:
3.1.2 + 3.2.1
Updated:
2013-03-15 12:46:05
Tags:
bios
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Description:
gene expression for prokaryotes end and eukaryotes expression
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  1. When cAMP is present... (4)
    -cAMP binds to CAP

    -cAMP/CAP complex bind to the CAP site in DNA

    -RNA polymerase binds the promoter efficiently

    -transcription occurs frequently
  2. When cAMP is absent (3)
    -CAP does not bind to DNA

    -RNA polymerase binds the promoter inefficiently

    -transcription occurs rarely
  3. (glucose influences formation of CAP/cAMP complex) When extracellular glucose concentrations are high...(4)
    -enzyme is inactive

    -intracellular cAMP are low

    -no CAP binding

    -transcription is decreased

    -cell continues to use glucose as energy source
  4. (glucose influences formation of CAP/cAMP complex) When extracellular concentrations of glucose are low..(4)
    -enzyme is active

    -intracellular cAMP concentrations are high

    -CAP binds

    -increases transcription

    -cell uses lactose, if it is present
  5. What does the enzyme adenyly cyclase produce?
    cAMP from ATP
  6. How is adenylyl cyclase inhibited?
    by extracellular glucose
  7. What is the outcome of glucose high and lactose low? (4)
    -no CAP site

    -promoter is bounded loosely

    -repressor protein on DNA, blocking transcription

    -very infrequent transcription

    (top)
  8. What is the outcome of Glucose high, LActose High? (4)
    -no CAP in the CAP site

    -promoter bound loosely

    -repressor protein falls off DNA, because lactose is binded

    -infrequent trasncription occurs
  9. What is the outcome is glucose is low and lactose is high? (4)
    -CAP binds to CAP site

    -promoter is binded tightly to RNA polymerase

    • -repressor protein falls off DNA
    • *lactose binds to it

    -frequent transcription occurs
  10. What does regulation of gene expression do? (2)
    -allows eukaryotic cells to respond to changes in the environment and;
  11. -causes distinct cell types to develop developmentally
  12. In Eukaryotes, what needs to happen to DNA before trasncription can occur?
    DNA must be opened
  13. What does alternative splicing allow a gene to do?
    allows a single gene to code for several different products
  14. Once mRNA is in cytoplasm, gene expression is controlled by molecules that regulate the following 3 things
    -life span of mRNAs

    -the efficiency of translation

    -the activation or inactivation of protein products
  15. 6 steps of eukaryotic gene expression) 1st step (2)
    Chromatin remodeling

    - open DNA to allow enzymes to access the DNA strand
  16. 6 steps of eukaryotic gene expression) 2nd step (2)
    transcription

    • -primary transcript is made
    • *pre mRNA
    • *still includes introns
  17. 6 steps of eukaryotic gene expression) 3rd step (2)
    RNA processing

    • -make a mature mRNA
    • *add the CAP and tail
    • *remove the introns
  18. 6 steps of eukaryotic gene expression) 4th step (2)
    mRNA stability

    -comes out of nucleus heads to ribosome
  19. 6 steps of eukaryotic gene expression) 5th step
    translation

    -creating a polypeptide
  20. 6 steps of eukaryotic gene expression) 6th step (2)
    -post translational modification

    -modifying the protein
  21. What does a nucleosome structure contain?
    -DNA

    -H1 protein

    -histone proteins
  22. WHat charge do histones carry?
    a positive charge
  23. WHat do histones contain?
    lots of lysines and/or arginines
  24. What charge does DNA have?
    negative charge
  25. What gives DNA its charge?
    • phosphate groups
    • *they make DNA negative charge
  26. Histones AND DNA
    They enjoy interacting with each other because of the opposite charge
  27. What resulted in formation of fibers?
    interactions between histone proteins and DNA
  28. What does the histone acetyl transferase (HAT) do? (2)
    -opens chromosome for transcription

    - attaches an acetyl group to chromosome
  29. Why does HAT attach an acetyl group to chromosome? (2)
    • when it attaches an acetyl group, it reduces the number of positive charges on histone
    • *makes it uncoil because the electronegativity decreases between DNA and Histone
  30. What is histone deacetyl transferase (HDAC) ? (2)
    -packs chromosome closed

    • -takes teh acetyl group off the chromosome
    • *it makes DNA condense
  31. what do methyl transferases do?
    turn on or off a gene
  32. What is epigenetic modulation? (2)
    • -turning on or off genes by methylating and acetylating them
    • *this can go across generations without changing DNA
  33. What is the TATA binding site in basal promoter region?
    it is where TATA binding protein binds that is essential for transcription

  34. What does the promoter proximal element do? (2)
    • -has a site that binds specific regulatory proteins that promote specific gene trasncription
    • **right next to promoter region

    - no regulatory protein no gene expression
  35. What are enhancer sites?
    if a regulatory protein binds here (regulatory site) it greatly enhances transcription
  36. Can enhancers be located in an intron?
    yes
  37. What are silencer sites?
    binding of different proteins to the regulatory sites like silencer sites, significantly reduce transcription
  38. 4 steps that extracellular signals trigger cell-specific expression
    1. signal arrives at cell with message "become a muscle cell"

    2. signal transduction results in production of intracellular signal

    3. Regulatory proteins are produced or activated in response to intracellular signal

    4. regulatory proteins bind to regulatory sites in DNA, triggering expression of muscle-cell specific genes
  39. Alternate splicing in eukaryotic cells allow it to..
    have one gene that encodes for a number of different but related proteins

    *ex) codes for smooth muscle and skeletal muscle in same gene but only splices the smooth muscle
  40. What is more important, number of genes or the variiety of the genes?
    • the variety of genes.
    • *it is more important how many proteins in different variance we can produce
  41. RNA interference
    smal specific pieces of RNA can ultimately lead to the destruction of other mRNA that is out in a cell

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