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Flashcards in Enzymes Deck (34)
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What is a catalyst?

A substance that increases the rate of a chemical reaction but does not get used up/changed/altered


What is an enzyme?

A protein molecule made by cells and acts as a catalyst


How are enzymes made?

By protein Synthesis


What are intracellular enzymes?

Only work inside of cells


What are extracellular enzymes?

Only work outside of cells (either in environment or in lumen)


What is specificity?

The relationship between an enzyme and the only type of molecule that fits into its active site


What are active sites made of?

A few amino acids within a polypeptide


What two things do eynzymes catalyse?

The breakdown and buildup of biological molecules


What three things can you infer from the name of an enzyme?

First part is the substrate, second is the reaction, and should end in 'ase'


What do we know about carbohydrase?

The substrate is carbohydrates, the reaction is hydrolysis, and it is an enzyme (its a hydrolase enzyme - catalyses hydrolysis)


If an enzyme is less specific?

Can catalyse a number of reactions of the same type


How specific is subtilisin - breaks peptide bonds between any AA?

Not very


How specific are trypsin and chymotrypsin?

Quite, only breaks bonds between certain AA, chymotrypsin (more specific)


What is an enzyme-substrate complex?

Complex formed when a substrate fits into an enzymes active site


Lock and key hypothesis?

Active site is complementary in shape to the substrate like a lock (enzyme) and key (substrate)


Enzyme-product complex?

Complex formed in the active site after the reaction is complete but before product(s) leaves


Induced-fit hypothesis?

Active site of an enzyme changes shape during binding of a substrate molecule, putting a strain on the substrate molecule and contributing to the reaction


Activation energy?

Energy needed to overcome the energy barrier to allow a reaction to occur


How do enzymes effect the activation energy of a reaction?

Provide alternative pathway with a lower activation energy


Model of activation energy?

Energy barrier is the hump at the top of a hill, AE is the energy needed to push a ball over the hump (EB) and down the hill (the reaction), with an enzyme the energy barrier and energy needed is decreased (smaller hump) m


Investigating enzyme activity for milk protein solution with protease?

10cm3 of milk solution to tube 1, 10cm3 of protease to test tube 2, put both in 25 degrees water bath for 5 mins, mix together the two tubes, time how long it takes for cloudiness to disappear


Rate of reaction?

1/time taken for substrate to disappear or product to to appear


Why put enzyme and substrate both in bath separate?

To equilibrate them


Optimum temp?

Temp when ROR is at max and a decrease or increase in temp will decrease the ROR


Increase in temp?

Increase KE of molecules, mols move faster, chance of collisions is higher, more successful collisions occur = more product formed


How do enzymes denature?

Molecules vibrate, increased KE and vibration strains the enzyme and weakens hydrogen and ionic bonds which hold the tertiary structure, once tertiary structure alters = active site is not complementary


Temp coefficient?

Ratio between the ROR of two different temps for the same reaction (ROR at x + 10 degrees/ROR at x degrees =Q10)


What is ph?

Concentration of H+ ions in a solution (A decrease of 1 PH is a x10 difference in H+ ions)


How does ph effect enzymes?

Due to the active sites hydrogen bonds, a big change in H+ ions will break some of the AS bonds, enzyme can lose shape and get denatured also far away from neutral


How does ph differ from temperature when denaturing enzymes?