Essential Question

why is ph & temperature important to enzyme function?

Lesson headings

1 what are enzymes?
2 why do living things need chemical reactions?
3 how can enzymes become denatured?

1 What are enzymes?

• Enzymes are proteins that help speed up chemical reactions.

• Enzymes are considered "functional" proteins.

  • Enzymes can either break substances ("substrates") down or put substances together.

• Enzymes are specific: they can only break down one (1) type of substrate.

• The place where enzymes and substrate meet = the active site.

1 What are enzymes?

• Enzymes fit into the substrate like a key fits into a lock.

• Enzymes have a very specific shape and structure.

• Enzymes usually end in "-ase" (for example, lactase)

1 What are enzymes?

• Enzymes are re-usable.

  • Once enzymes break down a substrate, they can move on to break down more substrates.

• Enzymes remain unchanged by the chemical reaction.

2 Why do living things need chemical reactions?

• Everything that happens in an organism is based on chemical reactions.

• A chemical reaction is a process that changes one set of compound to another. Some occur slowly and others occur quickly.

• Elements (compounds) at the beginning of the chemical reaction are called reactants; elements at the end of the chemical reaction are called products.

• Chemical reactions involves changing the bonds that make up these compounds.

• Changing these bonds require energy.

2 Why do living things need chemical reactions?

• Some reactions release energy; others require energy. Energy changes determine whether a chemical reaction will occur.

• The energy needed to get a reaction started is called activation energy.

2 Why do living things need chemical reactions?

• Enzymes work to lower activation energy. Enzymes are called biological catalysts.

3 How do enzymes become denatured?

• In order for enzymes to work properly, they must remain within a certain pH and temperature range.

• pH measures how acidic or basic a substance is.

  • Substances 1-6 are acidic; 7 is neutral; 8-14 is basic.

3 How do enzymes become denatured?

• When enzymes are placed in certain pHs and temperatures, the shape of the enzyme can change or become denatured.

• When enzymes become denatured, they no longer function properly.

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