Block One Lecture 11
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In bacteria, __ is rare.
Explain tertiary and secondary.
tertiary: secondary layer of folding--> more 3D--> 4 bonds (H bonds, ionic, S-S)
secondary: hydrogen bond dependent
ionic bonds: opposite charges create a weak electrostatic bond
S-S: only form with amino with sulfonated side chains
interaction of peptide subunits. Must ahve primary, secondary, and tertiary to get the quaternary structure.
Subunits must be folded correctly
not many structural features that enable quaternary structure
- 10^9 times more frequent than in eukaryotes
- --> transformative mutations, nonsense, point, etc. (any change)
UV light--> thymine dimers
can be extracellular genetic material
mutation that arises apart from any mutagens
most result in bacterium dying because the mutation would have messed with an important gene
a misplaced stop codon (causes a shortened protein)
- bases added or lost from genetic material
- --> at point of change, every codon after that point is obliterated--> stop codon is no longer there--> protein goes on and on until it happen upon a codon
humans use excision repair to fix int
- if change is greater than 5, the cell breaks apart and dies
- - ionizing nicks
- - can't hold genome into 3D structure
Once excision nicks occur, the cell dies because it can't hold the genome into 3D structure
Why is bacteria mutation rate high?
because they don't have good repair systems
What is vertical gene transfer?
new cells have slightl different genetic makeup than parent cell
Horizontal gene transfer
can acquire things from nature; they can hand off things
___ is turned to a single strand from a double strand.
protein essential for the repair and maintenance of DNA
strand goes off chromosome and new strand goes on
Gram positive cells do what?
You need a __ (overgrown culture) to have the bacteria come in contact with __.
release competence factors, which are secreted by cells.
What does ComD kinase do?
tells cell CF is low-> activates series of genes to be expressed--> transformasome--> interacts with bacterial DNA that's outside cell, stabiliizes it to have it go inside cell
What happens once inside cell?
- it is linearized and turned into a single strand
- (after its in, its broken down)
Once inside, recA proteins go to work. It's added to primary genome in pieces
Some gram negative bacteria can try toform __. Why is it not possible?
they have to go throguh the inner membrane, membrane, cell wal, periplasmic space. It's too complicated. Therefore, they do something else
So, what do gram negative do?
use pilus to randomly get DNA, uptake it, detect three and five prime ends
two cells get together, mostly gram negative.
the pilus attaches, F+ factor is replicated and the cell begins to copy the materia
Sometiems, in newly transformed cells, the __ integrates into the bacterial chromosome.
Sometimes, the F factor is successful in transforming __ cells; sometimes, regular DNA gets transmitted.
very commonly in gram negative
bacteriophage infects bacterial cell
virus is the vector
if bacteriophage carries bacterial DNA as opposed to viral DNA, it will form
What does methylase do?
preserves and modifies endonuclease
Cut sites for type two are __
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