Chapter 7
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What is the central dogma?
What is DNA and how do the strands fit together? How is base-pairing involved in DNA
synthesis? What does complementary mean? Anti-parallel? How do the bases pair (A/T,
C/G)?
What is a replication fork? What does semi-conservative mean in regards to DNA
synthesis? Origin of replication?
Which direction is DNA synthesized in? What is the difference between the lagging
strand and the leading strand? What are Okazaki fragments? What is DNA polymerase,
ligase and primase? What are their roles in DNA replication (briefly)?
How does DNA become RNA? What is the process called? What is the relationship
between DNA and RNA (i.e. the –stranded DNA and the + stranded mRNA—The RNA
is transcribed from the –strand and is complementary to it, meaning if the DNA sequence
is ATTCGGGA, the mRNA sequence would be UAAGCCCU)?
How does the RNA polymerase know where to start and stop?
What is the relationship between the amount of mRNA in a cell and the amount of the
protein that it codes for?
What is translation and what RNA/protein is involved? What is the role of tRNA in this
process?
The genetic code is mostly universal. Why is this interesting?
Why are ribozymes interesting to people who study the origin of life on earth?
Transcription is regulated by repressors and activators. What is an inducer? A corepressor? How do these interact with repressors and activators and what happens when
they bind to these proteins?
How do bacteria sense what is going on in their environment?
What is the lac operon and how is it regulated? Note: I will not ask you to detail the
entire process from scratch (as in, I will not ask: explain the entire regulatory pathway of
the lac operon).
o But, you should understand how each step works and how those steps fit together.
For instance, if I ask “How does the bacteria sense there is high glucose in the
media?” you should be able to answer “The glucose gets transported inside the
cell where the R (transporter component) becomes unphosphorylated, which
signals to the cell that there is glucose present.”
o Or if I ask “would the lac operon (genes) be turned on in the presence of high
glucose and high lactose?” you should know that they are not on (this is because
the unphosphorylated transporter component (R) blocks the lactose transporter, so
the cell can’t take up any lactose, therefore there is no allolactose in the cell so the
repressor sits on the lac operon DNA preventing transcription).
What is quorum sensing? Why might a bacteria only want to induce (turn on) a gene
when the bacterial cells are at high concentration?