Question

how enzymes work
in the diagrams below do the following:

1. label the active site of the enzyme
2. label and colour the enzyme blue
3. label and colour the substrate red
4. label and colour the product green

key ideas
words to use
example: low, product, biological, thousands, active site, complementary, activation, unchanged, specific, catalyst, substrate
enzymes are known as ____ catalysts. the enzyme has an __ __ which the substrate molecule is able to fit into. the substrate molecule is said to have a __ __ shape to the enzyme’s active site. enzymes are said to be __ to just one ____ for this reason.
when the substrate and enzyme molecules temporarily combine it is known as an enzyme-substrate ____. as the enzyme holds the substrate molecule in a certain way it puts tension on the substrate molecule. this lowers the __ energy needed for the reaction to take place. this is why reactions can occur at relatively ____ temperatures in living things.
during the reaction the substrate is turned into ____. this is released from the enzyme’s active site and the enzyme molecule is left __ and free to __ more reactions. each reaction in our body involves a specific enzyme. we have ____ of different enzymes in our body.
(diagrams labeled 1, 2, 3 with shapes to label/color)

Answer:

To solve the fill - in - the - blanks about how enzymes work, we use our knowledge of enzyme biology:

Part 1 (Enzyme Basics)

• Enzymes are known as biological catalysts. Enzymes are biological molecules (usually proteins) that speed up chemical reactions in living organisms.
• The enzyme has an active site which the substrate molecule is able to fit into. The active site is the region of the enzyme where the substrate binds.
• The substrate molecule is said to have a complementary shape to the enzyme’s active site. This is the basis of the lock - and - key model (or induced - fit model) of enzyme - substrate interaction, where the substrate fits into the active site like a key in a lock (or with some conformational changes).
• Enzymes are said to be specific to just one substrate for this reason. Enzymes typically act on only one or a very few related substrates because of the specific shape of their active site.

Part 2 (Enzyme - Substrate Complex and Activation Energy)

• When the substrate and enzyme molecules temporarily combine it is known as an enzyme - substrate complex. This is the intermediate formed when the substrate binds to the enzyme's active site.
• As the enzyme holds the substrate molecule in a certain way it puts tension on the substrate molecule. This lowers the activation energy needed for the reaction to take place. Activation energy is the energy barrier that must be overcome for a chemical reaction to occur, and enzymes lower this barrier.
• This is why reactions can occur at relatively low temperatures in living things. Since enzymes lower the activation energy, reactions can proceed at the relatively mild temperatures found in living organisms.

Part 3 (Product Formation and Enzyme Reusability)

• During the reaction the substrate is turned into product. The substrate is chemically transformed into the product(s) of the reaction.
• This is released from the enzyme’s active site and the enzyme molecule is left unchanged and free to catalyze more reactions. Enzymes are not consumed in the reaction, so they can be reused to catalyze more of the same reaction.
• Each reaction in our body involves a specific enzyme. We have thousands of different enzymes in our body. Our bodies carry out a vast number of different chemical reactions, each of which may be catalyzed by a specific enzyme, and there are thousands of these enzymes.

Filled - in Text for Part 1:

Enzymes are known as \(\boldsymbol{\text{biological}}\) catalysts. The enzyme has an \(\boldsymbol{\text{active site}}\) which the substrate molecule is able to fit into. The substrate molecule is said to have a \(\boldsymbol{\text{complementary}}\) shape to the enzyme’s active site. Enzymes are said to be \(\boldsymbol{\text{specific}}\) to just one \(\boldsymbol{\text{substrate}}\) for this reason.

Filled - in Text for Part 2:

When the substrate and enzyme molecules temporarily combine it is known as an enzyme - substrate \(\boldsymbol{\text{complex}}\). As the enzyme holds the substrate molecule in a certain way it puts tension on the substrate molecule. This lowers the \(\boldsymbol{\text{activation}}\) energy needed for the reaction to take place. This is why reactions can occur at relatively \(\boldsymbol{\text{low}}\) temperatures in living things.

Filled - in Text for Part 3:

During the reaction the substrate is turned into \(\boldsymbol{\text{product}}\). This is released from the enzyme’s active site and the enzyme molecule is left \(\boldsymbol{\text{unchanged}}\) and free to \(\boldsymbol{\text{catalyze}}\) more reactions. Each reaction in our body involves a specific enzyme. We have \(\boldsymbol{\text{thousands}}\) of different enzymes in our body.