enzyme action

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what is the definition of an enzyme?
a biological catalyst
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what is a catalyst?
a substance that speeds up a reaction without being used up
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what type of protein is an enzyme ?
a globular protein
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what type of structure is an enzyme and what bonds holds it?
a tertiary structure held together by hydron and ionic bonds
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what is the reaction called when an enzyme and substrate combine ?
metabolic reaction (catalyse)
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what does intracellula mean?
catalyse reaction takes place in cells
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what does extracellular mean?
released from cells to catalyse reation outside the cell
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what is the definition of activation energy?
the amount of energy to start a chemical reation
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how do enzymes affect actication energy?
they lower actuvation energy meaning they lower the temperature so they speed up the reaction.
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what is the part of the reaction that lowers activation energy?
enzyme-substrate complex
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what are the basic steps to which an enzyme fits into the substrate?
1. the enzyme has to be a complemantary shape to the substrate 2. enzyme connects to the substrate 3. this forms an enzyme-substrate complex 3. they then form a enzyme product complex 4. the product is released
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how do reactions occure?
molecules collide due to kinetic energy, the more energy the faster the reaction
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what is the lock and key theory?
the theory shows that the activesite is the lock and the substrate is is the key and they fit exact into each other for the reaction to catalyse
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what is the induced theory?
this theory shows enzymes molecules change shape to fit the substrate molecules more closly. the active site and substrate still have to be complimentary.
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what are the main factors that effect rate of reaction of enzymes?
temperature, concentration of substrate and enzyme, PH, cofactors and coenzymes, inhibitors
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how does temperature effct the rate of reaction?
when temperature increases there is more kinetic energy there for increasing the amount of collisons. this means more enzyme-substrate complexes from.
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what happens when temperature increases too much?
when the temperature gets above optimum the molecules vibtrate too much destroying the hydrogen and ionic bonds changing the shape of the activesite- denaturing the enzyme so no more enzyme substrate complexes can form
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what is equilibration?
getting the enzyme and substrate at the same temperature
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how does the PH effect enzyme rate of reaction ?
1. changing ph effects the hydrogen ions which effect the hydron and ionic bonds this changes the tertiary structure.2. increasing the concentration will changes the charges around the activesite as hydrogen ions attach to negativly charged groups
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what is optimum ph for pepsin and where is it found?
found in the atomach and ph is 2
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what is the optiumum ph for tipsin ?
7.5 and found in the liver
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what is PH?
concentration of hydrogen ions
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what are the two ways ph effects enzymes?
interferring with the hydrogen and ionic bond 2. interact with negaivly charged r groups in active site- interfeers with substrate binding
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how does the enzyme concentration effect the rate of reaction?
more enzymes means there is more active sites for the substrate to react with. there is a greater chance the substrate will bind to the activesite. increases rate of reaction
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what is the limiting factore of enzyme concentration?
the substrates
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what ahppens to the enzyme rate of reaction when you increase the eubstrate concentration?
greater chance the substrate will collide with the enzyme. therefore as this increases so does the reaction. however it levels off and the enzyme molecule become the limiting factor.
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what are cofactors?
Any substance that must be present to ensure an enzyme controlled reaction takes place at an appropriate rate
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what are coenzymes?
lmall, organic, non protein molecules. Bind for a short period of time to the active site just before the substrate binds
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whre the three cofactors?
prothetic group, coenzymes, inorganic ion.
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what is a prostetic group and an example?
coenzyme thats perminantly part of an enzyme also found in proteins.
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how do prestetic groups work?
vital to the function and overall 3d shape of the enzyme also contribute to charges of the enzynme
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name the prosettic group found in haemoglobin
the haem group
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how do coenzymes work?
bind to the activesite for the same time as the substrate and take part in a reaction. they carry chemical groups between enzymes fro chemical reactions.
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name an example of a coenzyme
vitimum B helps pyzyole dehydrgenase
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what are inorganic ion confactoprs?
inorganic ions
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how do inorganic ions work?
binding of an ion makes the enzyme-substrate complex form more easily as it effects the charge distrubution.
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what are th two main sypes of inhibitors
competative and non-competative
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what is an inhibiter
substances that reduce the reaction rate in an enzyme-controlled reaction as the effect the enzyme molecule.
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whats are competative inhibitor and how do they work?
it is a molecule which has a similar shape to the substrate, they occupy the activesite froming enzyme-inhibitor complex. this prevents a reaction from happening as the substrate cannot eneter so the number of enzyme substrate complexes are reduced
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true or fals- competative inhibitor is perminant
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what are non competative inhibitors and how do they work?
do not compete for the activesite. instead they bind to another region on the active site. this then changes the shape of the activsite so the substrate no longer fits. it is perminant and cant be reversed
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can a competative inhibitor be reverse?
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how are enzymes used to treat cystic vibrosis?
the tablet given contains enzymes packaged in acid resistant coating so not destropyed by the acid in the stomache. helps digest the persons food by overcoming the blockage.
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why is snake venom toxic?
1. contains an inhibitor of an enzyme which involved in nerve tarnsmission and results in paralysis. 2. atp-ase breaks down atop which disrups the prays use of energy. 3. interfeers with prays heart- low blood pressure
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why is anti freeze poisoness?
ethylen glycol is in antfreeze which is not poisoness it when it is broke down in the liver by alchole dehydronase it becomes toxic and cause faility
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why is pottassium cyanide poisness?
inhibits cell respiration- non competative inhibitor for vital respiratory enzyme called cytochrone found in mitochrondria. it decrease use of oxygen which cause anerbicy repsire only- build up lactic acid
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