1. Metabolism and Energy

2. 5 minute free write Think about the word Metabolism.
What does it mean?
Why is it important to you?
What does it do for you?
Is it a long or short process?
Can it be controlled?
What affects metabolism?
Does metabolism occur anywhere else other than your body?

3. Metabolism
Metabolism is the sum of all chemical reactions that occur in the cell
Catabolism is the process of breaking down compounds into smaller molecules to release energy
Anabolism is the process of using energy to build larger molecules

4. Anabolism all the synthesis or "building up" reactions in a cells
results in the creation of organic compounds (proteins, lipids, glycogen) for energy storage, cell growth, repair, reproduction, etc.
requires energy (endergonic)
What are the energy sources?

5. Anabolism
Endergonic
Decreases entropy

6. Catabolism
organic compounds are broken down to release the energy stored in them
produces energy (exergonic)
ATP can be used for various cell activities, such as biosynthesis, transport, cell division, movement, bioluminescence, but some energy is also lost as heat.

7. Catabolism
Exergonic
Increases entropy

8. Catabolism
if this process occurs with O2 then it is biological oxidation and the products are CO2, H2O and lots of energy (captured as ATP)
if this process occurs without O2, then it is fermentation and much less energy is produced (still captured as ATP)

10. Metabolic Pathway
A metabolic pathway is a series of chemical reactions in living cells.
Each reaction is catalyzed by an enzyme

11. Metabolic Pathway A metabolic pathway may be linear or circular
The product (end substance) of one pathway may be the reactant (starting substance) of another.  
Often reactions in a pathway are reversible.

12. Metabolic Pathways All pathways have the following participants:
Substrates/reactants - substances that enter the reaction
 Intermediate products - compounds formed between the start and the end of the reaction
Enzymes - proteins that catalyze reactions
Energy carriers - usually ATP.  
End products/metabolites - substances produced at the end of the pathway.

14. Energy The ability to do work
What kind of “work” are we talking about in biology?

15. Forms of Energy At the simplest level, energy is classified as:
Kinetic – energy of motion
Potential energy – stored energy in an object at rest
Other forms of energy are really just forms of these two.

18. Forms of energy Kinetic Potential Thermal Light Sound Chemical
Into which of the two main categories would you place the rest?

19. Bond energy
Whenever a chemical bond forms between two atoms, energy is released.
The amount of energy needed to break a bond is the same as the amount of energy released when the bond is formed

20. Bond energy This amount of energy is called bond energy
Unbonded atoms can be considered to have more chemical energy than any compound

23. Endergonic Reactions
Any reaction that requires the input of energy is endergonic (“inward energy”)
Endergonic reactions do not proceed spontaneously

24. Exergonic Reactions
A chemical reaction that releases energy is exergonic (“outward energy”)
An exergonic reaction can proceed spontaneously

25. http://www. columbia. edu/cu/biology/courses/c2005/lectures/lec7_10

26. Thermodynamics The study of the energy of transformations in a system
There are two laws

27. First Law of Thermodynamics
Energy cannot be created or destroyed, but it can be transformed from one type into another and transferred from one object to another
E.g. the sun’s energy is used to create glucose therefore it is changed into bond energy

28. Enthalpy
∆H – overall change in energy that occurs in chemical reactions
∆H endothermic (heat is absorbed)
bonds are formed
∆H exothermic (heat is released)
Bonds are broken

29. Second Law of Thermodynamics
During any process, the universe tends toward disorder
Entropy (disorder) is always increasing
This law concerns the transformation of energy into unusable heat, or random molecular motion

31. 2nd Law and biological systems
Organisms are highly ordered – is life an exception to this law?
The second law only applies to closed systems and organisms are not closed systems

33. ATP
In cells, energy from catabolic reactions is used to power anabolic reactions
The source of energy that links these reactions is ATP, adenosine triphosphate
ATP is the major product of most catabolic pathways
ATP is the major source of energy for anabolic pathways

36. Cyclic nature of ATP
The use of ATP in a cell can be thought of as a cycle
Cells use exergonic reactions to provide the energy needed to synthesize ATP from ADP + Pi (inorganic phosphate) then they use the hydrolysis of ATP to provide energy for endergonic reactions

37. Electron Carriers
Redox reactions play a key role in the flow of energy through cells
Electrons that pass from one atom to another carry energy with them
The reduced form of a molecule carries more energy than the oxidized form

38. Electron Carriers
Electron carriers are compounds that pick up electrons from energy-rich compounds and then donate them to low-energy compounds
An electron carrier is recycled
NAD+ (nicotinamide adenine dinucleotide) and FAD (flavin adenine dinucleotide) are important electron carriers

39. Electron Carriers NAD+ and FAD are oxidized forms
NADH and FADH2 are the reduced forms

40. That’s all for today!