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15 Enzymescornell Notes

Enzymes are proteins that act as catalysts to speed up chemical reactions in cells. They lower the activation energy of reactions by binding to substrate molecules. Each enzyme has a specific active site that binds only certain substrates based on their complementary shapes. Examples of enzymes include lactase, which breaks down lactose, and amylase, which breaks down starch. Enzymes are affected by temperature and pH levels - working outside their optimal ranges can cause them to denature and lose their shape and function. Enzymes are essential to many biological reactions in the body.

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165 views2 pages

15 Enzymescornell Notes

Enzymes are proteins that act as catalysts to speed up chemical reactions in cells. They lower the activation energy of reactions by binding to substrate molecules. Each enzyme has a specific active site that binds only certain substrates based on their complementary shapes. Examples of enzymes include lactase, which breaks down lactose, and amylase, which breaks down starch. Enzymes are affected by temperature and pH levels - working outside their optimal ranges can cause them to denature and lose their shape and function. Enzymes are essential to many biological reactions in the body.

Uploaded by

Russel
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Class Notes

Name: _______________________________________
Topic: Enzymes Period:_______________________________________
Date: _______________________________________
Questions/Main Idea:
Notes:
• Enzymes are proteins that help molecules react with one
What are enzymes?
another
• Their monomers are amino acids.
• Enzymes are used by cells to trigger and control
chemical reactions.
• Without enzymes, several reactions in cells would never
occur or happen too slowly to be useful.
• In digestive enzymes, often end in “-ase”
• It is the process of changing one set of chemicals
(reactants) into another set of chemicals (products) by
What is a chemical
rearranging the atoms.
reaction?
• Reactants’ bonds are broken and new ones are formed in
the products.
What is a catalyst? • It is a substance that speeds up the rate of a chemical
reaction.
• It lowers the activation energy.
• It participates in the reaction but doesn’t change itself;
therefore it can be used over and over.

What is activation • It is the amount of energy needed to start a chemical


energy? reaction.
• Catalysts speed up chemical reactions by lowering their
activation energy.
• Enzymes are catalysts because they lower the activation
energy by holding molecules together to either help them
bind (synthesize) or help them break apart (decompose).

• Enzymes bind to or break molecules called substrates.


What is a substrate? • These substrates are the reactants that are catalyzed by
the enzyme.
What is the active site? • Each substrate and enzyme has a specific shape,
therefore enzymes bind to substrates based on shape.
• The site on the enzyme where the substrates bind is
called the active site.
What is the Lock and Key • Enzymes bind to the substrates based on their
Hypothesis? complementary shape.
• The fit is so exact that the active site and substrates are
compared to a lock and key.
• Most digestive enzymes are named for the foods
(molecules) they help react—lactase helps break down
lactose (milk sugar)
What are other examples of • Lactase breaks down lactose into glucose and galactose
enzymes and what they • Sucrase (the “sugar-clipper”): breaks down sucrose
break down? (common table sugar) into glucose and fructose
• Amalyse breaks down starch in your mouth and
stomach
• Lipase breaks down ats
• Pepsin breaks down proteins

How are enzymes affected Enzymes are NOT changed by the reactions they catalyze,
by the reaction? therefore they are reusable!
How can enzymes be • Enzymes each work best at a specific temperature and
affected? pH.
• Temperatures outside the correct range can cause
enzymes to break down or change shape.
• This break down is called denaturation.

Why are enzymes • Nearly every reaction in your body is helped by an


considered the body’s enzyme!
“workers”? • Remember—enzymes are proteins!

Summary:

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