intro to biochemistry Flashcards
what substances can food molecules be broken down into?
nutrients
fibre
salts
vitamins (fat soluble and water soluble)
what do anabolic pathways do?
make new proteins, lipids, membranes etc
what do catabolic pathways do?
breaks down substances to make energy
explain the general stages of a catabolic pathway
large molecules broken down into their constituent parts made into acetyl CoA put into the Krebs cycle produces reduced coenzyme electron transport chain
what is the advantage of pathway complexity
more steps = more points of control
allows them to adapt to the different conditions that the body is in
what mediates metabolism?
enzymes
what is flux?
the direction the reaction pathway goes in
how is flux controlled?
control of transport of substances into and out of a cell - cells compartmentalise things
regulation of enzymes
energetics
how are enzymes regulated?
enzymes can be turned on/off through post-transcriptional modifications
what is the cori cycle?
the metabolic pathway by which lactate in anaerobic glycolysis in the muscles moves to the liver and is converted back to glucose
name characteristics of flux limiting enzymes
found near the start of the pathway low activity unidirectional multiple subunits can be turned on or off
why do enzymes often go in one direction?
thermodynamics
how are regulatory enzymes controlled?
allostery
covalent modifications
protein synthesis
how does allostery control regulatory enzymes?
modifier binds to enzyme and changes 3D conformation of enzymes to make the active site more/less active
how do covalent modifications control regulatory enzymes?
addition of phosphate group to enzyme by another enzyme makes an enzyme more/less active
