1. Enzymes
Chapter 2: Section 2.5

2. Objectives
SWBAT explain the effect of a catalyst on activation energy.
SWBAT describe how enzymes regulate chemical reactions and maintain homeostasis.

3. Starter: How can this be possible

4. Catalyst A catalyst lowers activation energy.
Catalysts are substances that speed up chemical reactions.
decrease activation energy
increase reaction rate – speed up reactions.

5. Enzymes are catalysts in living things
Enzymes allow chemical reactions to occur under tightly controlled conditions.
Like inside of a cell or intercellular space.
Enzymes are catalysts in living things.
Enzymes are needed for almost all processes.
Enzymes are almost always proteins.

6. Detailed Definition Enzymes
UC Davis Site:
When we think about information and its reliability, the source is important. If you would like to read in detail about enzymes (at a college level) check out this website.

7. Point of Review Enzymes are proteins.
Proteins are what kind of Molecule?
Answer: a carbon-based molecule.
Proteins are made up of what?
Answer: they are made up of amino acids.
Proteins are polymers of amino acids (making amino acids monomers).

8. Reactions with and without enzyme
Substrate refers to your reactants

9. Enzymes function in a small range of conditions
Disruptions in homeostasis can prevent enzymes from functioning.
Enzymes function best in a small range of conditions (remember importance of water’s special properties – water is a buffer).
Changes in temperature and pH can break hydrogen bonds (remember, organisms have a very narrow range of temperatures, pH and other conditions in which they can survive).

10. An enzyme’s function depends on its structure.
An enzyme’s structure allows only certain reactants to bind to the enzyme.
substrates
active site
substrates (reactants)
enzyme
Substrates bind to an enzyme at certain places called active sites.

11. An enzyme’s function depends on its structure.
The lock-and-key model helps illustrate how enzymes function.
substrates brought together
bonds in substrates weakened
Substrates bind to an enzyme at certain places called active sites.
The enzyme brings substrates together and weakens their bonds.
The catalyzed reaction forms a product that is released from the enzyme.

12. Examples of Enzymes
Amylase – made by salivary glands and pancreas (facilitates the breaking down of starch and glycogen into glucose).
Amino acid tryptophan is the substrate for the synthesis of serotonin.
Serotonin is a steroid that is a neurotransmitter (a chemical substance that transmits nerve impulses across synapses).
Involved in mood, appetite, sleep, memory, learning and depression (upping levels tends to relieve depression).