Lecture 11 Flashcards
What defines nutritional needs?
ability to make building blocks
What is the role if fueling reactions?
produce 13 precursor metabolites and provide ATP and NADH
What are the 3 steps in the fueling reaction?
1) entry
2) feeder pathways
3) central pathways
How do substrates enter?
by diffusion or active transport
What are feeder pathways?
generate intermediate organic molecules needed for central metabolism
What are the central pathways?
make the 13 precursor metabolites common to all organisms
In Gram-negative bacteria how do water and dissolved ions get transported into the bacteria?
transport proteins as thy are blocked by the hydrophobic outer membrane
Water and hydrophilic solutes diffuse readily into the?
periplasm
What molecules can passively diffuse into the inner membrane?
Only water, oxygen, carbon dioxide, and ammonia can pass by simple diffusion (non-selective)
How does glycerol diffuse into the cell?
facilitated diffusion which is selective but requires NO energy
—-transport proteins
What are the 3 types of active transport?
1) ion-coupled transport
2) ABC (ATP-binding cassette)
3) group translocation
What is ion-coupled transport?
driven by electrochemical gradient (proton or sodium-motive force)
What is ABC (ATP-binding cassette)?
uses energy from the hydrolysis of ATP to move solutes into the cell
What is group translocation?
phospho-transferase (PTS) system
Is the PTS system found in all bacteria?
nope
What 3 sugars does the PTS system transport in e. coli?
1) mannitol
2) glucose
3) mannose
Why is phosphorylation important?
adds phosphate and traps sugar inside the cell
What are siderophores?
iron chelators in bacteria
Why is iron important?
specialized transporters, usually limiting in the environment
What type of pathway is the calvin cycle?
feeder pathways used by autotrophs
What is the goal of the calvin cycle?
fix carbon via RuBisCo
What is the energy cost for the calvin cycle?
extremely energetically expensive requiring 18 ATP and 12 NADPH per cycle
What are the 3 most common central pathways?
1) glycolysis
2) pentose phosphate cycle
3) TCA cycle
The synthesis is of what needs all 3 central pathways?
amino acids
What is chorismate?
precursor to the aromatic amino acids
