biology enzyme summary
Enzymes- reduce the amount of energy required for the reactions they catalyse [accelerate].
-thus, increasing the rate of reactions that occur in living organisms.
WITHOUT enzymes
: metabolism would be so slow at body temp. that insufficient energy would be available to sustain life.
-Many enzymes are “Intracellular”- used within the cell that produced them e.g. enzymes in respiration & photosynthesis
-Others are “extracellular”-they act outside the cells that produce them e.g. digestive enzymes
STRUCTURE: -made of proteins, folded so they have a specific active site.
-many enzymes also require a non-protein “cofactor”, in addition, to act, e.g. metallic ions as: iron, copper, calcium, magnesium.
-Co-enzyme: when the cofactor that acts with the enzyme to alter reaction rate, is an organic compound [e.g. vitamin]
Substrate: a compound act on by the enzyme
Product: the compounds as a result of enzyme action.
Lock and key theory: the complementary fitting of an enzyme and substrate [like a jig-saw]
“Induced-fit” theory of enzyme action: when active site varies from substrate and the two only fit after contact when the substrate induces a complimentary shape at the active site of the enzyme.
FACTORS AFFECTING ENZYME ACTIVITY: pH: an enzyme becomes less efficient if the variable value is greater or less than the optimal.
-change from optimal can change an enzymes shape, affecting its ability to combine with its substrate = inability to act= decline in the rate of metabolic reactions.
Temperature:
-most human enzymes optimal: 37 °C [normal body temp]
-HIGH temp= structure is permanently denatured [remaining inactive even when normal temp. returns]
-LOW temp= enzyme is inactive [however, active again when temp is normal]
Enzyme Concentration:
-if the amt. of enzymes is increased the amt. of product per unit of time increases, until no more substrate is available.
- [Enzymes are avail. For reuse/
-thus, increasing the rate of reactions that occur in living organisms.
WITHOUT enzymes
: metabolism would be so slow at body temp. that insufficient energy would be available to sustain life.
-Many enzymes are “Intracellular”- used within the cell that produced them e.g. enzymes in respiration & photosynthesis
-Others are “extracellular”-they act outside the cells that produce them e.g. digestive enzymes
STRUCTURE: -made of proteins, folded so they have a specific active site.
-many enzymes also require a non-protein “cofactor”, in addition, to act, e.g. metallic ions as: iron, copper, calcium, magnesium.
-Co-enzyme: when the cofactor that acts with the enzyme to alter reaction rate, is an organic compound [e.g. vitamin]
Substrate: a compound act on by the enzyme
Product: the compounds as a result of enzyme action.
Lock and key theory: the complementary fitting of an enzyme and substrate [like a jig-saw]
“Induced-fit” theory of enzyme action: when active site varies from substrate and the two only fit after contact when the substrate induces a complimentary shape at the active site of the enzyme.
FACTORS AFFECTING ENZYME ACTIVITY: pH: an enzyme becomes less efficient if the variable value is greater or less than the optimal.
-change from optimal can change an enzymes shape, affecting its ability to combine with its substrate = inability to act= decline in the rate of metabolic reactions.
Temperature:
-most human enzymes optimal: 37 °C [normal body temp]
-HIGH temp= structure is permanently denatured [remaining inactive even when normal temp. returns]
-LOW temp= enzyme is inactive [however, active again when temp is normal]
Enzyme Concentration:
-if the amt. of enzymes is increased the amt. of product per unit of time increases, until no more substrate is available.
- [Enzymes are avail. For reuse/