topic 1- metabolic pathways Flashcards
metabolism
the many thousands of chemical reactions occurring in a living cell
anabolic pathways
the build-up of large molecules from small molecules and they require energy
catabolic pathways
the breakdown of large molecules into smaller molecules and they release energy
metabolite
an individual molecule in a metabolic pathway
reversible step
the conversion of intermediate 1 to intermediate 2 by enzyme B
irreversible step
the conversion of glucose to intermediate 1 by enzyme A
alternative route
they allow certain steps in a pathway to be bypassed
diffusion
the movement of molecules or ions from a high to low concentration and down a concentration gradient
pores
proteins that have water filled channels. water molecules and certain ions can move from one side to the other and no energy is required. the molecules can move by diffusion or osmosis
pumps
active transport carriers
enzymes
biological catalysts that speed up chemical reactions
activation energy
the energy needed to break the chemical bonds in the reactant molecules and to start the reaction
induced fit
when the shape of the active site changes to better fit the substrate so it fits more closely
inhibitor
a substance that slows down or inhibits the rate of an enzyme catalysed reaction
competitive inhibitors
they compete with substrate molecules for the active site of the enzyme and they prevent substrate molecules from binding
