MIBO 2500: Ch 6 Microbial Metabolism: Fueling Cell Growth

all cells need to

synthesize new parts (cell walls, membranes, nucleic acids)

harvest energy to power reactions

metabolism

sum of chemical reactions in a cell

anabolic

assembles large molecules from smaller ones; requires energy

catabolic

breaks down large molecules into smaller ones; release energy

carbon and energy sources for a chemoorganoheterotroph

organic compounds and a chemical source of energy

metabolic pathway components for a chemoorganoheterotroph

1. chemical energy source

2. enzymes

3. atp

4. electron carriers (reducing power)

5. precursor metabolites

chemical energy source

a compound from the environment that provides energy directly or electrons to help generate energy

enzymes

required for converting compounds into usable components for cells

highly specific for substrates

not changed by reaction so a single molecule can be used again and again

name reflects function; ends in -ase

active site either breaks bonds of substrate or joins bonds of substrates together

regulation of allosteric enzymes

enzyme activity controlled by regulatory molecule binding to allosteric site

distorts enzyme shape, prevents or enhances binding of substrate to active site

competitive inhibition of enzymes

inhibitor binds to active site

chemical structure of inhibitor usually similar to substrate

concentration dependent; inhibitor blocks substrate

ex: sulfa drugs that block folate synthesis