L7 catabolic and anabolic reaction Flashcards
3 things a bacterial cell needs to be able to generate
energy source
carbon source
reducing power
what are precursor metabolites
compounds require to make an entire microbial cell
what are the three main pathways used to make precursor metabolites
glycolysis
TCA cycle
pentose phosphate pathway
how many of E.coli’s precursor metabolites are produced in glycolysis
6
how many of E.coli’s precursor metabolites are produced in TCA cycle
4
how many of E.coli’s precursor metabolites are produced in pentose phosphate pathway
2
how does a bacterial cell get precursor metabolites if it can only carry out glycolysis
from the diet
what are precursor metabolites used for ?
making amino acids
turned to proteins
to make structures (flagellum)
what do bacteria use for reducing power
NAD+
how do bacteria breakdown polymers for energy
using a diverse range of digestive enzymes
what are most of the bacteria’s digestive enzymes associated with
cell surfaces
what is solute movement in the cell membrane mediated by
integral proteins
what forms are integral membrane proteins found in
alpha helical
beta strands
3 classes of bacterial active transporters for E.coli
major facilitator super family
ATP binding cassette (ABC) family
Group translocation: phosphoenolpyruvate-dependant phosphotransferase system (PTS)
what does the major facilitator superfamily look like
12-14 transmembrane spanning helices
what are the major facilitator superfamily
single polypeptide secondary carriers
what is the major facilitator superfamily capable of
transporting small solutes in response to chemiosmostic gradients
what is a uniporter
one solute one way
example of a uniporter
Ca2+, driven by the gradient of H+
what is an antiporter
proton goes one way, solute goes the other
example of an anti-porter
sodium going in
H+ coming out
what is a symporter
solute is transported in with a proton
example of a symporter
lactose with a proton
Lactose permease
how does an ATP binding cassette transport solutes
using primary active transport with ATP as the energy source
what do ATP binding cassettes consist of
multi-subunits
two membrane spanning domains and two ATP binding sites + periplasmic binding protein
how many components does an ATP binding cassette consist of
5
group translocation is also known as the..
phosphotransferase system
what is group translocation used for
trapping a substrate inside the cell
where does the energy for group translocation (phosphotransferase system) transport come from
phosphate (PEP)
what kind of substrates get transported by phosphotranferase system
sugars
why is the group translocation diffferent to the ABC and major facilitator super family
the substrate appears modified inside the cell
how many ATP is used by the ABC
2
why are two ATP molecules useed by the ABC
because there are two ATP binding subunits
what two things can the periplasmic protiens bind to?
the substrate (B12 is an example) and the membrane spanning proteins
what happens to the membrane spanning protiens when the periplasmic protein binds with a substrate
undergoes conformational change to transport substrate across the membrane
how does ABC get energy
hydrolysis of ATP powers the transport system
which two forms of active transport result in an unmodified substrate in the cell?
major facilitator superfamily
ABC
what enzyme is phosphorylated by PEP during group translocation, what happens to the PEP
enzyme I which is found in the cytoplasm
it gets turned into pyruvate for the citric acid cycle
what happens after enzyme I is phosporylated
it transports the P to the HPr protein
which two protiens are within translocation are non-specifc
enzyme I and HPr
what happens after HPr is phosporylated
It phosphorylates enzyme IIa
what happes after enzyme IIa is phosphorylated
it phosphorylates enzyme IIb
what happes after enzyme IIb is phosphorylated
transfers the P group to enzyme IIc
what does enzyme IIc do with the phosphate
phosphorylates glucose
functions of enzyme IIc
membrane spanning protein that transport glucose across the cell and phosphorylates it during transportation
which components of the phosphotranferase system are specific
Enzyme IIa, IIb, IIc
what is meant by a specific component
the bacteria will synthesise different types of it according to which sugar is being transported
why is having a modified sugar advantageous
the P traps the sugar inside the cell
the bacteria doe not have to expend more energy modifying while in the cell
what are the advantages to active transport
High affinity: a competitive advantage for scarce resources
rapid response to a fluctuating environment
allows cells to accumulate against a conc gradient
disadvanatges ot active transport
require energy
more complex proteins
how are uniporters powered?
delta sigh
the electrical gradient
