Enzymes

  • Created by: charley
  • Created on: 17-08-18 12:12
Metabolic pathway
A sequence of enzyme-controlled reactions in which a product of one reaction is the reactant in the next
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Anabolic reactions
Building up molecules
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Catabolic reactions
Breaking molecules down
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Properties of enzymes
Globular proteins with tertiary structure. They're biological catalysts. Soluble due to the hydrophilic R groups
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Extracellular reactions
Enzymes are secreted by exocytosis and catalyse extracellular reactions
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Intracellular reactions (solution)
Enzymes act inside the cell
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Intracelular reactions (membrane bound)
Enzymes are attached to membranes
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The lock and key model
Theory that enzymes show enzyme specificity and can only catalyse one type of reaction
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Lysozyme and induced fit model
An enzymes shape slightly alters to accommodate the substrate
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The effect of temperature on enzyme activity
An increase in temperature increases kinetic energy which increases the probability of successful collisions, increasing the rate of reaction.
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The effect of temperatures higher than the optimum for the enzyme
The enzymes denature due to the increased vibrations breaking the hydrogen bonds. The structure of enzyme is permanently altered.
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The effect of low temperatures on enzyme activity
The enzyme is inactivated as molecules have little kinetic energy
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The effect of pH changes on enzyme activity
Small fluctuations cause reversible changes and reduce its activity. Large fluctuations denature enzymes due to the charged parts on the amino acids of the active site being neutralised, disrupting the ionic and hydrogen bonds and therefore its shape
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The effect of substrate concentration on enzyme activity
Rate of reaction increases as substrate concentration increases, until all active sites are occupied. the substrate is the limiting factor as it controls the rate of reaction
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The effect of enzyme concentration on enzyme activity
As the enzyme concentration increases, the rate of reaction increases
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The turn-over number
The number of product produced in a given time
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Competitive Inhibition
Have a shape similar to the active site and compete for substrates. They're reversible
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Non-competitive Inhibition
Bind to the enzyme at an allosteric site, effecting its overall shape and altering its active site. They're reversible unless they form covalent bonds.
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Immobilised enzymes
Enzymes are fixed/bound on an inert matrix. Substrates pass through a column and bind to the active sites. Enzymes don't contaminated the product and can be reused. Enzymes are more stable and don't denature as easily.
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Other cards in this set

Card 2

Front

Building up molecules

Back

Anabolic reactions

Card 3

Front

Breaking molecules down

Back

Preview of the back of card 3

Card 4

Front

Globular proteins with tertiary structure. They're biological catalysts. Soluble due to the hydrophilic R groups

Back

Preview of the back of card 4

Card 5

Front

Enzymes are secreted by exocytosis and catalyse extracellular reactions

Back

Preview of the back of card 5
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