1. Cellular Metabolism: An Overview
SBI4U Biology

2. Recall Some Metabolism Facts:
Metabolism = the use of energy
Catabolic & Anabolic Processes
Enzyme mediated
Mitochondrion
C6H12O6 + O2  H2O + CO2 + ATP

3. Cascades & Cycles Metabolic Reactions are linked
“chain reactions”… sort of.
Straight line = Cascade
Circular = Cycle

4. Cascades Think waterfalls and fountains
The product of one reaction becomes the reactant of the next.

5. Cascades
An example of an enzyme-mediated cascade.

6. Cycles Think carousels & wheels.
The product of each reaction becomes the reactant of the next, but the final reaction generates the first reactant again.

7. Cycles
An example of an enzyme-mediated cycle.

8. The Mitochondrion Four Metabolic Regions:
Outer Membrane: for fatty acid metab.
Inner Membrane (Cristae): enzyme-rich
Intermembrane space: tiny but vital!
Matrix: central fluid, also enzyme-rich

9. Each Eukaryotic Cell has many Mitochondria.
The Mitochondrion
Each Eukaryotic Cell has many Mitochondria.

10. The Four Metabolic Regions

11. The Mitochondrion Many Cristae = increased surface area
More places for reactions to occur
More enzymes to catalyze them

12. Extracting Energy A General Overview:
Initial Processing of Glucose in the Cell’s Cytoplasm.
Products move to Mitochondrion, for reactions in the Matrix.
Those products are processed by enzymes on the Cristae & in the Intermembrane space.

13. The path of Glucose & its products
Extracting Energy
The path of Glucose & its products

14. Stage 1: Glycolysis Glyco = Sugar Lysis = breaking
10 reactions that break down 6C Glucose into two molecules of 3C Pyruvate.
Cascade
In Cytoplasm.

15. Stage 2: Krebs’ Cycle Citric Acid Cycle
Continues with Pyruvate, which must enter the Mitochondrion
Ten Reactions
Cycle
In Matrix

16. Stage 3: Oxidative Dephosphorylation
Final stage
Chain of redox reactions
Cascade
On cristae & in intermembrane space.

17. Here’s how it all fits in:

18. Why do all of this? Gradual release of glucose’s energy
Formation of ATP – Adenosine Triphosphate
ATP = The energy ‘currency’ of all life.