5.1 biological catalysts Flashcards
what alters the rate of a chemical reaction, without being changed itself?
catalysts
define catalyst
a substance that increases the rate of a chemical reaction and is not changed by the reaction
what catalyst controls almost every metabolic reaction?
enzymes
define enzymes
important proteins that act as biological catalysts that speed up biochemical reactions without themselves being altered in the process
how do enzymes control the metabolic reactions?
enzymes ensure that the rates of metabolic reactions are great enough to sustain life
where are enzymes present in?
they are present in all living cells
enzymes convert _______ to _______
substrates; products
what are examples of enzymes in metabolic reactions?
- large molecules broken down to smaller ones in the process of digestion in the alimentary canal
- starch digested to the sugar maltose by an enzyme called amylase
- protein is digested to amino acids by protease
what is the enzyme that digests starch to sugar maltose?
amylase
what is the enzyme that digests protein to amino acids?
protease
process of enzymes in plants - germinating seeds
seeds contain starch>seed soaks up water>amylase is activated>breaks down starch to maltose>maltose is soluble>is transported to the embryo in seed>embryo uses maltose to provide energy for growth>also to provide glucose molecules that can be strung together to make cellulose molecules (for cell wall of new cells)
define catalase
an enzyme found in almost all living tissues, which catalyses the breakdown of hydrogen peroxide to water and oxygen
what is the lock and key mechanism?
enzymes works by allowing to the molecule of the substance on which it is acting to fit into it; enzyme is like a lock and another molecule fits like a key.
the shape of the enzyme and the shape of the substrate are ___________ to one another
complementary
define substrate
a substance in which an enzyme acts
the substance which is present at the beginning of the reaction
