Chapter 8- The molecular mechanisms that create specialized cell types

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Chapter 8- The molecular mechanisms that create specialized cell types
2014-10-30 04:59:18
Chapter 8-The molecular mechanisms that create specialized cell types.
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  1. When cells divide, do the daughter cells remember the changes in gene expression?

    What is this phenomenon called?

    Cell memory.
  2. Eukaryotic Genes are controlled by combinations of ________ ___________.

    Much of the intervening DNA serves as "_____" sequence and is not directly recognized by the transcription regulators.

    In contrast to simple prokaryotes, most eukaryotic transcription regulators work as part of a "__________" of regulatory proteins, all of which are necessary to express the gene in the right conditions.
    Transcription regulators


  3. The term _________ ________ refers to the way that groups of transcription regulators work together to determine the expression of a single gene.

    Are both repressors and activators present in the same complex?

    The effect of multiple transcription regulators combine to determine the final what?
    Combinational control


    Rate of transcription initiation.
  4. By a single what can the expression of different genes be coordinated by?
    A single protein.
  5. What is one way in which bacteria coordinate the expression of a set of genes?

    Is this the case for eukaryotes? If not, how?
    By having them clustered together in an operon under the control of one promotor.

    Each gene is transcribed and regulated individually.
  6. How can whole groups be switched on or off?

    What is an example of such coordinated regulation?
    1. As long as the different genes have regulatory DNA sequences that are recognized by the same transcription regulator, then the whole group can be regulated at once.

    2. Having the right combination of proteins with the final protein simply giving the right combination.

    Cortisol-receptor protein.
  7. How can a single transcription regulator coordinate the expression of many different genes, in the case of the cortisol-creceptor complex? Two step example. What happens when the concentration of cortisol decreases surrounding environment?
    • By all the genes being regulated by the cortisol-receptor complex and depending on it to bind to a regulatory sequence in DNA of each gene. 
    • 1. Inactive cortisol regulator forms a complex with a cortisol molecule.
    • 2. Complex binds to DNA regulatory sequence.
    • 3. In response to the cortisol and the complex binding, liver cells increase the expression of many genes.

    The gene expression of all the genes drops to its normal level.