1.7- ENZYME ACTION Flashcards
What type of protein are enzymes?
globular proteins
What do enzymes act like?
act as catalysts
What do catalysts do?
alter rate of chemical reaction without undergoing permanent changes themselves
Why are enzymes effective in small amounts?
can be used repeatedly
What do enzymes NOT do?
make reactions happen
What DO enzymes do?
speed up reactions that already occur
By what factor can enzymes sometimes increase a reaction by?
many millions
What must the substrates collide with?
sufficient energy
Why must the substrates collide with sufficient energy?
to alter the arrangement of their atoms to form products
What must the free energy of the products be like in comparison to the substrates?
free energy must be less than that of the substrates
What do many reactions require to start?
an initial amount of energy
What is the minimum amount of energy needed to activate a reaction called?
activation energy
What must initially be overcome before the reaction can proceed?
an activation energy level, like an energy hill or barrier
How do enzymes work?
work by lowering the activation energy level
As enzymes lower the activation energy what does this mean?
allow reactions to take place at a lower temperature than normal
As the reactions are allowed to happen at a lower temperature, what does this mean?
enables some metabolic processes to occur rapidly at human body temp. , 37 degrees Celsius
How is 37 degrees Celsius in terms of chemical reactions?
relatively low in terms of chemical reactions
What would happen to life without enzymes?
reactions would proceed too slow to sustain life as we know it
How are enzymes globular proteins?
have a specific 3D shape that is result of sequence of amino acids (primary structure)
What is the name of the specific region of the enzyme that is functional?
active site
What is the active site made up of?
relatively small number of amino acids
What does the active site form?
a small depression within the much larger enzyme molecule
What is the name of the molecule on which the enzyme acts on?
substrate
Where does the substrate fit into?
fits neatly into the depression
What is formed when the substrate fits into the active site of the enzyme?
enzyme-substrate complex
How is the substrate molecule held within the active site?
by bonds that temporarily form between certain amino acids of the active site and groups on the substrate molecule
How do scientists often try to explain their observations?
by producing a representation of how something works
What is the representations of how something works called?
scientific model
What is an example of a scientific model?
physical models used to explain enzyme action
What does the induced fit model of enzyme action proposes?
that the active site forms as the enzyme and substrate interact
What does the proximity of the substrate lead to?
a change in the enzyme that forms the functional active site
Why does the proximity of the substrate cause a change?
as there’s a change in the environment of the enzyme
In other words what can the enzymes said to be like?
the enzyme is flexible and can mould itself around the substrate
What happens as an enzyme changes its shape?
enzyme puts a strain on the substrate molecule
What does the strain exerted by the enzyme do?
distorts a particular bond or bonds in the substrate molecule
As bonds are distorted due to the strain, what happens?
lowers the activation energy needed to break the bond
What is any change in an enzyme’s environment likely to do?
change its shape
Why does the very act of an enzyme colliding with a substrate cause it to change shape?
as it is a change in environment of the enzyme- induced fit
