Enzymes

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What is another name for an enzyme?
Biological catalyst
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why are enzymes called biological catalysts?
they speed up metabolic reactions in living organisms
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what is the turnover number
the number of reactions that an enzyme can catalyst per second
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give two reasons why enzymes are so remarkable?
1. they are more specific than chemical catalysts and do not make un-wanted prodcuts 2 can function in neutral pH and lower temperatures than chemical catalysts
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how many amino acids on the active site?
6-10
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what is the importance of the tertiary structure of the active site?
it must be complimentary to the substrate molecule
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what can affect the active site of the enzyme
changes in temperature and pH
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what makes an enzyme highly specific?
it can only catalyse reactions that involve a specific substrate
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what is a metabolic pathwat?
a series of consecutive reactions
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what happens in a catabolic pathway
metabolites are broken down to smaller molecules and release energy
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what happens in an anabolic pathway
energy is used to make larger molecules from smaller ones
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where is catalase found
nearly all organisms that are exposed to oxygen
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how does catalase work?
it protects cells from damage by breaking down hydrogen peroxide
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what is the structure of catalase?
four polypeptide chains and a haem group
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what is an extracellular enzyme?
where enzymes are secreted from the cells where they are made
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what is an example of an extracellular enzyme
amylase is made in the salivary glands and acts in the mouth
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what is a cofactor
a substance that has to be present so a reaction can take place at an appropriate rate
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what is a prosthetic group
a non protein group that is permanently bound to an enzyme molecule
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what is a co-enzyme
they bind temporarily to the active site of enzyme molecules
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what happens to co-enzymes during a reaction
they are chemically changed during a reaction and need to be recycled back to their original state
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what are the two theories of enzyme action?
lock and key hypothesis and induced-fit hypothesis
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what is the lock and key hypothesis
fill in the blank
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what is the induced fit hypothesis
fill in the blank
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why do enzymes lower the activation energy?
enzymes have a specific active site so there is no need for excess heat
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How does heat affect kinetic energy
increase in heat means that there is an increase in kinetic energy, increasing the rate of successfull collison
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What happens when an enzyme is denatured?
ionic and hydrogen bonds break so the tertiary structure of the e enxyme chanegs
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what is the meaning of optimum temperature?
the temperature at which anenzyme works best
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what is the temperature coefficinet?
the increase in the rate of a reaction when the temperature of a reaction is increased by 10 degrees
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what is a buffer?
a substance that resists change in pH
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how does a change in pH affect bonds in molecule
fill in blanks
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what is the effect of changing substrate concentration
fill in blanks
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what is enzyme degredation
cells constantly degrade old enzymes to their amino acids
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what are the advantages of enzyme degredation
1. abnormally shaped proteins are eliminated 2. extra enzymes are eliminated and this regulates metabolism
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How does increasing enzyme concentration affect reactions
fill in blank
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why is the initial rate of reaction the fastest
fill in blanks
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what ate the three types of inhibition
competitive, non-competitive and end product
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what is a competitive inhibitor?
the inhibitor fits into the active site so there are less enzyme active sites
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what is a non-competitive inhibitor?
binds to an allosteric site and changes the shape of the active site so the substrate can non longer bind
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what is end-product inhibition
product molecules may stay tightly bound to the enzyme so the enzyme can no longer for complexes
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what are two metabolic poisons that act as enzyme inhibitors?
cyanide and snake venom
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what are five medicinal drugs that act by enzyme inhibition
aspirin, ATPase inhibitoes, ACE ibhibitors, protease inhibitors and nucleoside reverse transcriptase
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how do ACE inhibitors work?
they drugs inhibit ACE enzyme that increases bloodpressure.
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what do ACE inhibtors treat?
patients with hypertension who cant take beta blockers, minimis risk of heart attack
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Other cards in this set

Card 2

Front

why are enzymes called biological catalysts?

Back

they speed up metabolic reactions in living organisms

Card 3

Front

what is the turnover number

Back

Preview of the front of card 3

Card 4

Front

give two reasons why enzymes are so remarkable?

Back

Preview of the front of card 4

Card 5

Front

how many amino acids on the active site?

Back

Preview of the front of card 5
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