Biology - Enzymes
- Created by: Dariaxx
- Created on: 17-10-16 11:40
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- Biological molecules - Enzymes
- Globular proteins that act as catalysts
- catalysts alter the rate of a chemical reaction without undergoing permanent change
- Enzymes as catalysts lower activation energy
- there is an activation energy, like an energy hill or barrier, which must initially be overcome before reaction proceeds
- enzymes work by lowering the activation energy level.
- In this way enzymes allow reaction to take place at a low temperature than normal
- This enables some metabolic processes to occur rapidly at the human body temperature
- without enzymes these reactions would proceed too slowly to sustain life as we know it
- This enables some metabolic processes to occur rapidly at the human body temperature
- In this way enzymes allow reaction to take place at a low temperature than normal
- Factors Effecting Enzyme Action
- Temperature
- A rise in temperature increases the kinetic energy of molecules
- As a result, the molecules move around more rapidly and collide with each other more often
- In an enzyme-catalysed reaction, this means that the enzyme and substrate molecules come together more often in a given time
- If the temperature keeps keeps increasing it causes the hydrogen and other bonds to break. Also changes the shape of the active stite
- In an enzyme-catalysed reaction, this means that the enzyme and substrate molecules come together more often in a given time
- As a result, the molecules move around more rapidly and collide with each other more often
- A rise in temperature increases the kinetic energy of molecules
- pH
- A change in the pH alters the charges on the amino acids that make up the active site
- As a result, the substrate can no longer become attached to the active site
- depending on how significant the change of pH is it may cause bonds maintaining the enzyme tertiary structure to break
- A change in the pH alters the charges on the amino acids that make up the active site
- Enzyme concentration
- An increase in the amount of enzyme leads to a proportionate increase in the rate of reaction
- There is more substrate than the enzymes active sites can cope with
- An increase in the amount of enzyme leads to a proportionate increase in the rate of reaction
- Substrate concentration
- If the concentration of enzyme is fixed and substrate concentration slowly increased, the rate of reaction increases in proportion to the concentration of substrate
- at low substrate concentration, the enzyme are not working at their full capacity
- If the concentration of enzyme is fixed and substrate concentration slowly increased, the rate of reaction increases in proportion to the concentration of substrate
- enzyme inhibition
- competitive inhibitors
- which bind to the active site of the enzyme
- prevents substrate from temporarily binding
- which bind to the active site of the enzyme
- non-competitive inhibitors
- which bind to the enzyme at a position other than the active site
- changes the shape of the active site
- which bind to the enzyme at a position other than the active site
- competitive inhibitors
- Temperature
- measuring rate of change
- we can measure change inthe rate of a reaction at any point on the curve of a graph
- we do this by measuring the gradient at our chosen point
- we can measure change inthe rate of a reaction at any point on the curve of a graph
- measuring enzyme-catalysed reactions
- the formation of the products of the reaction, for example the volume of oxygen produced when the enzyme catalase acts on hydrogen peroxide
- the disappearance of the substrate, for example the reduction in concentration of starch when it is acted upon by amylase
- Globular proteins that act as catalysts
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