What are enzymes?
Biological catalysts that are globular process which lower activation energy causing reactions to occur at much faster rates
What are anabolic reactions?
The building up of large molecules from small molecules
What are catabolic reactions?
The breaking down of large molecules into smaller ones
What is metabolism?
The sum of all reactions and reaction pathways within a cell or organism
What is Vmax?
The maximum initial velocity or rate of enzyme catalysed reaction. The maximum rate of reaction of an enzyme
Explain the lock and key hypothesis
Specific substrate will fit the active site of one specific enzyme
What happens when an active site is bound to a substrate in the lock and key hypothesis?
Enzyme substrate complex is formed
Substrate and active site form temporary bonds between R groups (puts strain on bonds in the substrate)
Enzyme product complex formed
What does the induced fit hypothesis state?
Active site of enzyme slightly changes as substrate enters.
Explain, in terms of bonds, what happens during the induced fit hypothesis
Intitial interaction=weak
Enzymes tertiary structure strengthens bonding
Puts strain on bonds inside molecule, then weakens them
Lowers activation energy
What are intracellular enzymes?
Enzymes that work within cells
Give an example of an intracellular enzyme and what it breaks down
Catalase- breaks down hydrogen peroxide
What are extracellular enzymes?
Enzymes that work outside the cells they are produced in
Give 2 examples of extracellular enzymes and explain what they do
Amylase and Trypsin, break down the large molecules into smaller molecules so that they can be absorbed in the bloodstream and through cell membranes
Explain the process of starch digestion
1) Starch broken down into maltose via amylase in saliva and small intestine
2) Maltose is broken down into glucose via maltase in the small intestine
3) Glucose is absorbed into the cells in digestive system
What is trypsin and what is its role?
A protease that catalyses digestion of proteins
Produced in the pancreas, passes into small intestine in pancreatic juice
What does an increase in temperature do to enzyme activity? (not including too high temperatures that cause denaturation)
Increases kinetic energy of particles
More frequent collisions
More frequent successful collisions between enzyme and substrate
Increased rate of reaction
What is the temperature coefficient of a reaction?
A measure of how much the rate of reaction increases with a 10 C increase in temperature
What is the temperature coefficient for enzyme controlled reactions?
2
Explain how an enzyme becomes denatured by temperature in terms of bonds
Higher temperatures-bonds holding the protein together vibrate more
Vibrations increase
Bonds strain
Bonds break
Change in precise tertiary structure- conformational change
Why can an enzyme no longer react when it has been denatured?
Active site changes shape and is no longer complementary to substrate. Can’t bind. No function
How are enzymes adapted to cold environments?
Flexible structures, specifically active site
How are enzymes present in thermophiles adapted?
More stable due to increased number of bonds (hydrogen and disulfide bridges) in tertiary structures
What is renaturation?
When pH changes from optimum temperatures the enzyme is denatured, however if pH returns to optimum levels the enzyme returns to original shape
What happens to tertiary structure of an enzyme at low pH?
Less R groups are able to interact
Bonds break
Shape of enzyme changes- conformational change
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Cells67
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Biological Molecules150
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Enzymes48
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Plasma Membranes48
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Cell Division74
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Exchange Surfaces and Breathing57
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Transport in Animals80
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Transport in Plants88
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Biodiversity59
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Classification56
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Communicable Diseases164
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Neuronal Coordination174
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Energy for biological processes66
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Respiration60
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Hormonal Communication72
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Homeostasis56
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Plant Hormones59
