Enzymes Flashcards
what are enzymes?
biological catalysts
what biomolecules are enzymes made of?
proteins
what is a catalyst?
a substance that changes the rate of a reaction without itself being used up
what do enzymes do?
speed up reactions in the cell that would otherwise be too slow to sustain life
what is metabolism?
the sum total of all of the chemical reactions in an organism
5 main things that the reactions in the body involve
growth movement reproduction response homeostasis
what do cells need to function properly?
energy
the way in which energy is obtained and utilised in the cell
metabolism
2 types of reactions
anabolic
catabolic
anabolic reactions
small molecules to larger ones
energy is required
catabolic reactions
larger molecules to smaller ones
energy is not required, it is released
do anabolic reactions need enzymes?
yes
do catabolic reactions need enzymes?
yes
example of anabolic reaction
photosynthesis
example of catabolic reaction
respiration
what controls the rate of reactions in a cell?
enzymes
2 main sources of energy for living things
solar energy
cellular energy
what is solar energy?
it is trapped by organisms that contain pigments which can absorb light eg. chlorophyll
what is cellular energy?
held in biomolecules. capable of being released by reactions within a cell
3 steps in transfer of energy
solar energy
cellular energy in biomolecules
energy used to do work
what types of proteins are enzymes?
globular proteins
enzyme specificity
one enzyme will generally only react with one substrate
2 things that makes enzymes change
temperature
pH
enzyme inhibitors
chemicals that attach to the enzyme acive site and destroy their shape
optimum rate of an enzyme
the fastest rate an which an enzyme can work
substrate
substance with which an enzyme reacts
product
the substance(s) the enzyme forms
are enzyme reactions reversible
yes, they can go in both directions
active site
region of the enzyme that bonds with the substrate
why are enzymes specific?
because all of their active sights are different
4 steps, induced fit model
- substrate binds to A S
- AS changes shape, binds better
- enzyme-substrate complex formed, turned into product
- product leaves active site and AS changes back
how fast do the 4 steps happen?
very fast, up to 1,000 times a second in some enzymes
what is a denatured function
lost its shape and has a permanent lost of function
2 causes of denaturing
- high temperatures
2. unsuitable pH
explain denaturing by high temperature
will gradually begin to lose 3D shape when heated to 40ºC and will be permanently denatured at 50ºC
rate of a reaction
amount of product formed per unit of time
rate of reaction experiment
substrate product enzyme
substrate: hydrogen peroxide
enzyme: catalase
products: water+oxygen
rate of enzyme action at 0ºC
very low
why would rate of reaction be low in low temperatures?
very little movement of molecules, less collisions occur between substrate and enzymes
optimum temperature for enzymes in human body
37ºC
optimum temperature for enzymes in plants
20ºC - 30ºC
optimum pH for most enzymes
7
optimum pH of pepsin in the stomach
2
optimum pH of salivary amylase in the mouth
7
optimum pH of pancreatic lipase
9
3 types of catabolic enzymes
amylase
protease
lipase
2 anabolic enzymes
DNA ligase
RNA polymerase
DNA ligase
used in genetic engineering to join two pieces of DNA together
RNA polymerase
build long chains of RNA during transcription
3 commercial uses of enzymes
- bio washing powders
- rennet to make cheese
- digest pectin (polysaccharide found in plants) cloud in fruit juices, wine and beer
bioprocessing
the use of enzyme controlled reactions to produce products
bioreactors
a vessel or container in which living cells or enzymes are used to make a product
what has replaced microorganisms in making bread, cheese, wine and beer
purified enzymes
why would you imobilise enzymes?
done so that they can be reused over and over again
what is an imobilised enzyme? 3 points
in a fixed postion
made insoluble
unable to move
how can an enzyme be imobilised ?
sticking them to the surface of an inert (unreactive) substance, by enclosing them in a gel or fixing them to each other
which enzyme breaks down pectin?
pactinase
which enzyme beaks down lactose
lactase
what is lactose broken down into
glucose and galactose
what enzyme changes glucose into sweeter fructose?
glucose isomerase
which enzymes are used in bio detergents
proteases
which enzyme alters penicillin to make new antibiotics?
penecillin acylase
3 advantages of immobilised enzymes
- can be reused -> cheper
- product purer, enzyme stays in biorector, doesn’t contaminate the product
- immobilsed ones are more stable, reduces amount needed
