Chapter 4.2 Flashcards
What are enzymes?
Speed the rates of metabolic reactions
Most enzymes are
globular proteins that catalyze specific reactions in cells by lowering the activation energy required to start these reactions.
Enzymes can speed
metabolic reactions by a factor of a million or more
What is catalysis?
The acceleration of chemical reaction rate
Enzymes are required in small amounts because
as they work, they are not consumed and can, therefore, function repeatdly
What is a substrate?
Each enzyme type is specific, acting only on a particular type of molecule
Substrate of an enzyme called catalase is
hydrogen peroxide, a toxic by-product of certain metabolic reactions
What is lipase?
A lipid-splitting enzyme
What is Protease?
A protein-splitting enzyme
Amylase
A starch-splitting enzyme
What can sucrase?
splits the sugar sucrose
what is maltase?
splits the sugar maltose
what is lactase?
splits the sugar lactose
What is the active site on the enzyme molecule?
it temporality combines with parts of the substrate molecule, forming an enzyme-substrate complex
Many enzyme-catalyzed reactions are
reversible
The rate of an enzyme-catalyzed reaction depends partyle on
the number of enzyme and substrate molecules in the cell
The reaction is faster if
the concentration of the enzyme or the concentration of the substrate increases
Many enzymes become inactive at
45 Celsius
Nearly all enzymes denature at
55 Celsius
Metabolic PAthways lead
to the synthesis or breakdown of particular biochemicals.
Rate-limiting enzyme
When increasing the substrate concentration no longer affects the reaction rate
What is a cofactor?
Some enzymes become active only when they combine with a nonprotein component
A cofactor helps
the active site fold into its appropriate conformation or helps bind the enzyme to its subtrate
What is a coenzyme?
A cofactor that may be an ion of an element,
