control of metabolism Flashcards
what are the levels of regulation of cellular metabolism
intracellular region (cells) intercellular region (whole body)
intracellular regualtion
aim to maintain metabolic homeostasis
match rates of metabolic pathways to availability of substrates and requirement for ATP
what influences intracellular regulation
concentration of substrates
allosteric activation and inhibition of metabolic enzymes
covalent modification of metabolic enzymes
substrate channeling
what leads to the Michele’s mentalis curve
availability of substrates
rate of metabolic reactions is dependant on availability of substrates
allosteric interations
binding of a substrate other than AS can have a postive/negative effect
covalent modifications
e.g. phosphorylation
substrate channeling
enzymes able to convert the same substrate into different products
gene expression
enzyme levels can be increased by increased synthesis, decreased degradation ect
intercellular regualtion
liver adipose brain muscle coodinate together to regulate the whole body
what is intercellular regulation mediated by
hormones
nervous system
substrate availability
hormone regulation in energy metabolism
insulin
glucagon
insulin
two pp chains with disulphide bridges
synthesis of insluin
preproinsulin to proinsulin to insulin
precursor has its signal sequence removed and exocytosis
C chain removed to form active form
secretion of insulin increased by
glucose
amino acids
gastrointestinal hormones
inhibition of insulin causes
fasting
stress
extreme exercise