Microbial Enzymes Flashcards
Metabolism
collection of controlled biochemical reactions that take place within a microbe; ultimately the function is to reproduce the organism
Catabolic pathways
breaking down larger molecules into smaller molecules
Anabolic pathways
synthesizing larger molecules from smaller ones
Metabolic Processes with eight statements
Every cell acquires nutrients.
Metabolism requires energy from light or catabolism of nutrients.
Energy is stored in adenosine triphosphate (A T P).
Cells catabolize nutrients to form precursor metabolites.
Precursor metabolites, energy from A T P, and enzymes are used in anabolic reactions.
Enzymes plus A T P form macromolecules.
Cells grow by assembling macromolecules.
Cells reproduce once they have doubled in size.
Exergonic (Catobolism)
releasing energy, which then is stored at ATP or lost as heat
Endergonic (anabolism)
require more energy than they release, which typically provided by ATP, but also lost as heat
Enzymes
organic catalysts, increase the likelihood of a reactions which then lowers the activation energy
Substrate
the molecule the enzyme acts on
Makeup of enzymes
many protein enzymes are complete in themselves; apoenzymes are inactive until they are bound to one or more nonprotein substances called cofactors (inorganic ion or coenzyme which is organic derived from a vitamin); the binding of apoenzyme and its cofactor forms and active enzyme called a holoenzyme
Ribozymes
not all enzymes are proteins; some are RNA enzymes
Induced fit
a perfect fit between the enzyme and substrate does not occur until they bind and form a complex and the enzyme’s active site changes to fit the substrate more closely
Steps in a reaction
Enzyme makes a perfect fit with substrate; the substrate then breaks, forming two or more products; the enzyme dissociates from the new products; the enzyme then changes back into its original shape
Temperature - enzymes
if temp rises beyond a certain point, the non-covalent bonds within an enzyme will break and will denature
pH - enzyme
extremes of pH will also denature enzymes when ions released from acids and bases interfere w hydrogen bonding and distort enzyme secondary and tertiary structure.
Competitive inhibitors
a molecule similar in structure to a substrate can bind to an enzyme’s active site and compete with substrate
Noncompetitive inhibitors
attach to the enzyme at an allosteric site, which is a site other than the active site; distort the tertiary protein structure and alter the shape of the active site
Feedback inhibition
regulates the rate of many metabolic pathways when an end product of a pathway accumulates and binds to and inactivates the first enzyme in the metabolic pathway; the end product then binds itself to the allosteric site of the enzyme
