Text Book enzymes Flashcards
Catalyst
they reduce the activation energy of a chemical reaction and increase the rate without being used up themselves remaining unchanged
Turnover number
the number of substrate molecules converted per second
What breaks down glycosidic bonds/ester bonds
Glycosidase
esterase’s
What can a non-functioning enzyme cause
may lead to serious disease as it may mean that a metabolic reaction cannot proceed properly
Why is the daily amount of nicotinamide so low
1) The NAD is recycled/regenerated after it has been changed during an enzyme-catalysed reaction in which it is used as a coenzyme.
What bond does a co-enzyme form
ionic
How do enzymes lower the activation energy
bring the substrate molecules close together, as the substrate molecules fit into the enzyme’s active site, and form S–E complexes, and stay there long enough to reac
How can there be multiple reactions taking place at the same time in a cell
substrates are catalysed by a specific enzymes meaning that there an be many different enzymes within the cell at once
-Many reactions take place in different organelles and so are separate from each other
Disulphide bridges
Are heat stable
Why can an enzyme still catalyse a reaction after it has been cooled but not when it has been heated
Cooling the enzyme slows the rate of reaction but does not permanently alter the molecular structure. So, on warming to 40°C, enzyme molecules gain KE and can move again – they catalyse the reaction. Enzymes that have been boiled are denatured and this involves irreversible change to the shape of the active site
Independent variable
this is the variable that the investigator changes to find out how the DV is affected.
Dependant variable
varies as a result of changing the IV
pH
changes the balance of H ions/protons which can alter the shape of the enzymes active site if this interferes then the active site of the enzyme can be altered and no longer complimentary to the substrate so an ESC can no longer be formed
-make bonds outside its tertiary structure
Why do fungi/bacteria have the enzyme urease
to breakdown urea that is in the soil (derived from nitrogenous waste/urine) to ammonia that can be absorbed and used to make new amino acids, for protein synthesis.
Controlled in an enzyme reaction and why
If temperature changes, the enzyme and substrate molecules will have more or less KE and this will alter rate of collision/rate of formation of ES complexes/formation of product molecules.
(b) If time alters, there will be more/less time for ES complexes to form, so more/less product will form.
(c) If reactant molecules are well mixed, this increases the chance of collisions/formation of ES complexes, so will increase rate of reaction.
(d) Wavelength affects absorption and this is what is being used to measure rate of reaction
Why do cells regulate the amount of enzymes
1) Cells only have a particular amount of enzymes to make sure that metabolic reactions happen at a particular rate and not too much product is accumulated which would also waste energy where it was not needed
Amino acids that have not come from the degradation of enzymes
Comes from the digestion of proteins from food
End product inhibition
The product molecules may remain bound to the enzyme/regulatory subunits of enzyme, keeping the enzyme in its inactive form (the active site may not be exposed). Many metabolic pathways are regulated by different enzymes that form a large multi-enzyme complex. The end product may bind to an enzyme early in the pathway.
How does the presence of organelles within a cell increase the efficiency of metabolic reactions
Many enzyme molecules that each catalyse a stage in a metabolic pathway are enclosed together within organelles. As the product from one reaction is the substrate for the next, the diffusion distance is greatly reduced and this decreases time for product/substrate to reach the active site of the next enzyme.
Enzyme degradation benefits
Gets rid of any abnormally large proteins
regulation of metabolism by the elimination of nay superfluous enzymes
What does smoking inhibit
amylase; can’t tell which type of inhibition as there is no data on substrate concentration
