Lecture 3.2: Bacterial Genetics 2 Flashcards
does a flagella undergo Brownian motion?
no
energy involved the flagella is driven by the
sodium ion pump
swimming phenotype can be monitored using__
motility agar
what are the 3 parts of the flagella?
- basal body
- hook/rod
- filament
where is the basal body located?
inside the cell envelope
where is the hook/rod located?
anchored to cell envelope, outside the cell
where is the filament located?
completely outside cell
what part of the flagella is most protein abundant?
the filament
flagellar gene expression is linked to __
cell cycle, nutrient availability
flagellar genes are ___ from ___ locations on the chromosome
co-transcribed; multiple
gene expression if hierarchial based on ___
morphogenesis
describe gene expression based on morphogenesis
as soon as one structure is done being made, those genes turn off and turn on genes for the next structure
the mater operon concerns what class of genes?
early
the master operon is made of __
Fihc 2and Fihd2 proteins that form a tetrameric complex
the fich/fihd complex acts as ___- for the beginning of flagellar biosynthesis
entry level regulator
fichd gene expression is controlled by (5)
- catabolic repression
- cell state sensors
- temperature
- inorganic salts
- nutrients
fihcd links motility to
immediate environment
class 2 genes rely on __ gene expression
sigma 70
__- acts as an activator. How does it work?
fihcd. Binds to DNA, allowing RNA polymerase to bind
fichd binds to DNA and RNA polymerase is what way
cis-specifically
what is the flagella specific sigma factor is encoded from class 2 genes?
sigma 28 (FliA
what is the role os sigma 28 in class 2 genes?
confers specifically for class 3 genes via RNA polymerase
a ___ in any of the 34 class 2 genes prevents ___
mutation; expression of class 3 genes
protein assays show that sigma 28 interacts with ___
FlgM
if there is a mutation in class 2 genes, sigma 28 is __ and __
present; inactive
FlgM is know as
the anti-sigma factor
the anti-sigma factor prevents
expression of class 3 genes
flgM and sigma 28 are controlled by the same
transcriptional control
when there is a mutation in class 2 genes, __ accuulates
FlgM
why have an anti-sigma factor?
to prevent the filament from being made before the hook is ready for it (especially in poor environments)
what causes class 3 genes to activate?
de-repression of FlgM (letting it out of the cell)
the flagella is a “reversible structure” because it is capable of ___ and ___ motion
cw and ccw
the energy obtained from ion movement is transferred into __ energy
rotational
bacteria are able to move on motility agar because it is __
not completely solid
how can you tell if a bacteria has moved using motility agar?
circles will form are bacteria use nutrient and swim to the next source
name the rings of the basal body from inside out
c, ms, p, L
why is there strong selection for tight, efficient regulation of flagellar expression?
they are energetically very expensive
early genes are responsible for
turning on first and then turning on class two genes
middle genes are responsible for
making protein (hook and basal)
late genes are responsible for
making filament and cap
FlhCD are ____ once flagella are made
autorepressers
at least __ transcriptional sites have been identified on the master operon
6
6 transcriptional sites of the master operon means 6 __
inputs
what is the result of having 6 start sites on the master operon?
more FlhCD that will lead to expression of middles genes
function of sigma 70 in class 2 gene expression
allows RNA polymerase to bind and turn on genes
flgM is secreted from the bacteria through
the hook basal structure
in the making of a flagella, genes get turned on and structures are made, but alsoooo
structures get made and genes get turned on
the making of the flagella is an example of development leading to ___
expression
