1. Cellular Metabolism
Chapter 4

2. Metabolism
All the chemical reactions that occur in a cell

3. Two general types of metabolism
Anabolic reactions- making larger molecules from smaller ones
Catabolic reactions- breaking down larger molecules into smaller ones
Anabolism + catabolism = metabolism

4. Anabolic
Ex: dehydration synthesis, combines smaller molecules into bigger molecules (plus water)

5. Anabolic steroids
Reaction that increases production of proteins (and can inhibit catabolism of proteins)

6. Catabolic
Example: hydrolysis, breaking down larger molecules by adding water, produces smaller molecules

7. Control of metabolic reactions
Most reactions proceed at a particular rate/speed
Must put in energy to cause a reaction
Amount of energy put in to start reaction is called “Activation energy”

8. Speeding up reactions

9. Speeding up reactions
Enzymes- produced by our bodies, proteins that speed up reactions by lowering activation energy, identified by –ase suffix (e.g., protease)
Not consumed in chemical reactions, so your body can reuse them
Highly specific- typically only one enzyme type only recognizes one molecule

10. Enzymes Makes it easier to break the bonds between molecules
Substrate is molecule(s) involved in the reaction
Active site is part of the enzyme that combines with the substrate
Substrate
Enzyme
Sucrose
Fructose
Glucose
Active site

11. Optimal conditions for enzymes
pH and temperature have dramatic effects on enzymes
Ex: Too high a temp denatures enzymes and they can’t work

12. Getting energy from metabolism…

13. Energy Capacity to change something, ability to do work
Common forms: heat, light, sound, electrical, chemical energy
Can transform from one form to another

14. Why do we eat?. . . To make ATP
ATP (Adenosine triphosphate)—the energy currency of the cell
Foods are metabolized (chemical bonds are broken) to produce ATP
ATP
ATP
Eat food.
Digest food.
Transport food to cell.
Use to make ATP.

15. Cellular Respiration Cellular Respiration—the process of making ATP
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + 38 ATPs
(Glucose)
Cellular Respiration—the process of making ATP
Carbohydrates, fats and proteins are all metabolized and fed into biochemical pathways that make ATP.