Enzymes

Descripción

Fichas sobre Enzymes, creado por mollie.dawson el 24/03/2015.
mollie.dawson
Fichas por mollie.dawson, actualizado hace más de 1 año
mollie.dawson
Creado por mollie.dawson hace más de 9 años
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Resumen del Recurso

Pregunta Respuesta
What are enzymes? (3) Globular proteins Have a specific tertiary structure Catalyse metabolic reactions in living organisms
What is a catalyst? A substance which speeds up a chemical process without being used up in the reaction itself
Is enzyme action intracellular or extracellular? Both
What type of protein is an enzyme? Globular
What determines the active site? Tertiary structure
What lowers the activation energy? Formation of enzyme-substrate complex
How can activation energy be lowered? (2) When two molecules are joined via enzyme Breakdown reaction via enzyme
How is activation energy lowered when two molecules are joined? They attach to enzyme which holds them together - reducing repulsion effect
How is activation energy lowered in a breakdown reaction? Fitting into the active site puts a strain on bonds, so molecule breaks easier
How does the induced fit model differ from the lock and key model? Induced fit model incorporates that the enzyme-substrate complex changes shape slightly to fit
What affects rate of reaction? (4) Temperature pH Enzyme concentration Substrate concentration
How does temperature affect rate of reaction? (4) Higher temperature makes enzyme molecules vibrate more If temp goes above certain temperature, vibrations break some bonds which hold enzyme together Active site changes shape Enzyme is denatured
How does pH affect the rate of reaction? Enzymes have an optimum pH Above & below optimum, H+ and OH- ions in acids and alkali's mess up ionic & hydrogen bonds that hold tertiary structure
What does catalase catalyse? Breakdown of hydrogen peroxide into water and oxygen
What does Amylase catalyse? Breakdown of starch to maltose, iodine detects starch
What does an inorganic cofactor do? Help the enzyme and substrate to bind together
So are inorganic cofactors changed or used up in any way? No
What are manganese ions? Cofactors found in hydrolase
What are organic cofactors called? Coenzymes
What do coenzymes do? They act as carriers, moving chemical groups between different enzymes
Are coenzymes altered during reactions? Yes, they're continually recycled
So what is a coenzyme? An organic cofactor which participate in the reaction and changed by it, they move chemical groups between enzymes and are continually recycled during this process
Can enzyme activity be inhibited? Yes
What is competitive inhibition? Competitive inhibitor molecules have a similar shape to substrate, they compete with substrate molecules to bind to active site, block active site so no reaction
What is non-competitive inhibition? Non-competitive molecules bind to enzyme away from its active site, causing active site to change shape, so substrate molecules can't bind to it
What type of bond creates an irreversible inhibitor? Strong, covalent bond
What type of bond creates a reversible inhibitor? Weak, hydrogen/ionic
What is a metabolic poison? An enzyme inhibitor
What is cyanide an irreversible inhibitor of? Cytochrome c oxidase, which catalyses respiration reactions
What does penicillin do? Inhibits transpeptidase, which catalyses the formation of proteins in bacterial cell walls, weakening cell wall, Boom, bacterium has burst
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