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Biology - 2.4 Enzymes > Enzymes > Flashcards

Flashcards in Enzymes Deck (18)
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What are enzymes?

they are proteins that speed up rate of reaction by acting as a biological catalyst


What do biological catalyst do?

they catalyse metabolic reactions - both at cellular level (e.g. respiration) and for organism as a whole (e.g. digestion)


What can enzymes affect?

structures in an organism as well as function


What is catalase and the role of it?

Its an enzyme that works inside cells to catalyse the breakdown of hydrogen peroxide to harmless h2o +o2. H2O2 is the toxic by-product several cellular reactions. if left to build up, it can kill cells.


where do amylase and trypsin work?

they work outside cells in the human digestive system.


where is amylase found and the role of it?

> Amylase is found in saliva. its secreted into the mouth by cells in the salivary glands.
> It catalyses the hydrolysis of starch into maltose in the mouth.


whats the role of Trypsin? and how is it produces?

>it catalyses the hydrolysis of peptide bonds - turning big polypeptides into smaller ones (which then get broken down into amino acids by other enzymes).
> its produced by cells in the pancreas and secreted into smaller intestines


what shape are enzymes?

globular shape


what is the active site?

its the part of the enzyme where the substrate molecules bind to


what shape does and active site have and what is it determined by?

active site has a specific shape, which is determined by the enzymes tertiary structure


For the enzyme to work...

...the substrate shape has to be complementary.


what is an enzyme-substrate complex?

its when an enzyme substrate binds to an enzymes active site.


what is activation energy?

its the amount of energy of energy which needs to be supplied to the chemicals before the reaction start


what reduce the amount of activation energy thats needed?

enzymes reduce the amount of activation energy thats needed, making reactions happen at lower temperatures than they could without an enzyme which speeds up the rate of reaction.


What lowers the activation energy?

when an enzyme substrate complex is formed it lowers the activation energy


how does an enzyme substrate complex been formed lovers the activation energy?

> because if molecules are joined, it reduces any repulsion between the molecules so they can bond more easily
> if its a breakdown reaction, fitting into the active site puts a strain on bonds in the substrate which means the molecule break up easily


explain lock and key model

its where the substrate fits into the enzyme in the same way as a key fits into a lock - the active site has a complementary shape.


Explain induced fit model

its where the substrate binds to active site and cause change in the shape of active site to be even more complementary to the substrate. This outs a strain on the bonds & make it more likely to read.