1. Metabolism
(Chapter 6)

2. Bioenergetics - energy flow in systems
Metabolism = all the chemical reactions that take place within cells

3. Carbohydrates Breakdown of glucose (respiration)
C6H12O6 + 6O2→ 6CO2 + 6H2O + energy
Synthesis of glucose (photosynthesis)
6CO2 + 6H2O +energy → C6H12O6 + 6O2

4. Anabolic vs Catabolic Pathways

5. Potential vs Kinetic Energy
Energy of position
Energy of motion

6. Endergonic reactions require energy. (pushing a ball up a hill)
Exergonic reactions release energy. (rolling a ball down a hill)
Activation Energy = the energy required to start a chemical reaction.

7. First Law of Thermodynamics Second Law of Thermodynamics
Energy can be transformed, but it can never be created or destroyed.
Second Law of Thermodynamics
The state of entropy of the entire universe will always increase over time. (Entropy is a measure of “randomness”)

8. Adenosine Triphosphate (ATP)

9. Enzymes - catalyze biochemical reactions
Reactions occur faster and with less activation energy needed

10. Enzymes bind to substrates at the active site
Induced fit model of enzyme function (also called the “lock and key” model

11. Properties of Enzymes:
Enzymes are made of proteins.
They are needed only in small amounts
They remain unchanged after each reaction and can therefore be reused
Each enzyme is specific for a substrate

12. Degradation vs Synthesis breaking down vs building

13. Biology Pro-Tip Most enzyme names end in the letters -ase
The enzyme that breaks down sucrose is ….. SUCRASE
The enzyme that breaks down lactose (milk sugar) is…
LACTASE

14. Factors Affecting Enzymatic Speed
1. Substrate concentration 2. Temperature & pH * 3. Enzyme concentration
Enzymes can be denatured - they change shape so much that they are no longer effective. High temp or pH can cause denaturation. 

15. Siamese cats have an enzyme that works at lower temperatures only, causing the nose and ears to become a darker color than the rest of the body.

16. Enzymatic Inhibition - when a substance binds to an enzyme and decreases its activity. (Usually reversible)
Competitive Inhibition 
Noncompetitive Inhibition (allosteric site)
**Both are forms of feedback inhibition

17. Some inhibitors are NOT reversible - poisons like cyanide, lead poisoning all affect enzymes
QUESTION: What type of inhibition is pictured below?

19. Feedback Inhibition

20. Enzyme Lab(s) 2H2O2 --------> 2H2O + O2
Hydrogen Peroxide is broken down by the enzyme: catalase within cells.   
To determine the speed of a reaction you can either
A) measure the amount of products produces (oxygen)
B) measure the amount of substrate (hydrogen peroxide) is left over when the reaction is stopped

21. The activity of catalase can be seen by the bubbling of oxygen during the reaction

22. Virtual Labs with Enzymes
McGraw Hill Lab

23. Enzyme Animation (Tutorial)
Enzyme Quiz