Lecture 14 - intro to metabolism Flashcards
catabolic
break down
energy release
anabolic
making molecules
store energy in chemical bonds
key reasons to have multistep metabolic pahway rather that a single step
single step: all or nothing, energy mostly as heat = inefficient
multipstep: smaller units of enry can be used by cells, each reaction has an enzyme = regulation
2 reasons why mwtabolic pathways need to be highly regulated
respond to environmental changes
avoid futile cycles
exception to futile pathway
glycolysis and glucogenesis
if both happen at same time - produces heat which is important in hibernating creatures
what does flow of material through a pathway depedn on
supply of substrate
removal of products
enzyme activities
3 mechanisms of regulation
- feedback inhibition
- feed forward activation
- inhibition or activation from other pathways
example of covalent modification of enzyme
protein phosphorylation
via protein kinases
(protein phosphatases remove phosphate groups and reverse this)
how to make an endergonic reaction happen
coupled reactions
example of coupled reaction
glucose phosphorylation catalysed by hexokinase
overall:
glucose+ATP -><- glucose6P + ADP
why does hexokinase change to close in on itself when glucose binds
keeps H2O out
means the phosp from ATP binds to the glucose instead of dissolving in solvent
autotrophic
either photosynthesis
or chemosynthesis
heterotrophic
energy from breakdown of organic molecules from other orgnaisms
how much atp formed and consumed every day on avg
~2.3kg
what is the -ve charge from the phosphates in an ATP offset by
Mg2+
