Enzymes

Learning Intentions

·        the role of enzymes as protein catalysts in biochemical pathways. 


·        the mode of action of enzymes including reversible and irreversible inhibition of their action due to chemical 
competitors at the active site, and by factors including temperature, concentration and pH

·        the cycling of coenzymes (ATP, NADH, and NADPH) as loaded and unloaded

·        forms to move energy, protons and electrons between reactions in the cell.

Engage

Watch the video Amoeba Sisters - The proteins that remind us of Pac-man



Activity 1 (5 minutes)
While you are watching the video identify 3  things you have learnt or know about enzymes as proteins. Some things to think about:

• What is an enzyme?
• Some examples of enzymes?
• Some features of enzymes?
• Function of enzymes?

Explore (20 minutes)
Activity 2 -Watch the video Bozeman (11:51). Add to your Cornell Notes while you are doing this. You do not need to understand everything but list any questions you may have. Below are some things to think about when taking your notes.

• What is catalyse? What is its role? What chemical reaction is it involved in?
• Draw an example of an enzyme? Label the parts.
• What is a substrate ? What is the substrate in the example?
• Explain the lock and key mechanism. Click here to see an animation of how lock and key mechanism works
• When are proteins activated in a cell? What triggers the activation in a cell?
• What are cofactors and coenzymes and what are their role in activation?
• What is an inhibitor?
• What variable can you measure that effect the reaction rate of enzymes. 

Explain
Note taking and answering questions PowerPoint on enzymes (20 minutes)

Activity 3 - Read Textbook Chapter 4. 1 and 4.2 Add to your notes. Answer the the key questions.

Elaborate

Activation Energy in enzymes
Catabolic reactions (exergonic reactions) -  release energy
Anabolic reactions (endergonic reactions) - require energy

Have a look at this video to understand more about activation energy and how enzymes lower the activation reaction of reactions.


Inhibition of enzyme activity

Watch this video to help understand and then define competitive and non competitive (allosteric) inhibition.

What is Feedback Inhibition?


Enzymes as cofactors and coenzymes

Coenzymes(organic e.g. vitamins and those involved in producing energy- ATP, NADH, FADH2 NADPH) and cofactors(inorganic)

Cofactors and coenzymes bind to the enzyme and help catalyse a reaction.

Evaluate
Review this chapter. Watch video and add anything you missed to your notes. Any of these videos cover the necessary information but I have placed them in order of my choices.
Work on chapter review question p 178-179

Other Resources

Khan Academy (8:12 minutes)
Enzyme Function, University of Surrey