L1 - control of cellular function Flashcards
what are the two components of metabolism?
anabolism = synthesis catabolism = breakdown
which component of metabolism requires energy?
anabolism, in the form of ATP, from photosynthesis (light) or respiration/fermentation (catabolism)
what are the compartments of plant and animal cells associated with energy and metabolism?
plants - photosynthesis = chloroplasts
animals - respiration = mitochondria
what are changed to control metabolism?
enzyme catalytic activity
enzyme concentration
what controls catalytic activity of enzymes?
molecules bind non-covalently to an enzyme
covalent modification of an enzyme
what controls enzyme concentration?
changes in protein biosynthesis and breakdown
what is the most important type of covalent modification of enzymes?
phosphorylation
what charge does a phosphate group have?
negative
what does phosphorylation do?
changes the charge on a protein so modifies protein structure and enzyme activity
what type of amino acids does phosphorylation mainly occur on?
amino acids with HYDROXYL groups: serine, threonine, tyrosine
how is enzyme activity increased or decreased?
by phosphorylating specific amino acids side chains, often Ser
phosphorylation often stimulated by specific hormones
what happens to enzyme activity in glycogen metabolism?
phosphorylation increases the activity of the degradative enzyme and decreases the activity of the synthetic enzyme
what controls differentiation?
changes in activities and concentrations of enzymes
what can cause changes in concentration and catalytic activity?
differentiation and in response to environmental signals
what is an example of covalent modification?
phosphorylation
