1. Energy and Metabolism

2. The Energy of Life
The living cell generates thousands of different reactions
Metabolism
Is simply all the organism’s chemical reactions
All molecules (nutrient molecules included) have stored (potential) energy in the bonds between their atoms

3. Metabolic Pathways
A metabolic pathway has many steps that begin with a specific molecule and end with a product, each catalyzed by a specific enzyme
Reactions that join small molecules together to form larger, more complex molecules are called anabolic.
Reactions that break large molecules down into smaller subunits are called catabolic.
Enzyme 1
Enzyme 2
Enzyme 3 A B C D
Reaction 1
Reaction 2
Reaction 3
Starting molecule
Product

4. Metabolic Pathway

5. ALL Living Things from Bacteria to Humans Conduct METABOLISM
Two Kinds of Metabolic Reactions:
Catabolism = breakdown of large molecules into simple ones to produce energy. (release energy)
Anabolism = build large molecules from simple molecules. (requires energy input)

6. Energy Coupling
Living organisms have the ability to couple catabolic and anabolic reactions:
Energy released by catabolic reactions is captured and used to make ATP from ADP and Pi
ATP can be broken back down to ADP and Pi, releasing energy to power the cell’s anabolic reactions.

7. The Structure and Hydrolysis of ATP
ATP (adenosine triphosphate)
Is the cell’s energy shuttle
Provides energy for cellular functions O
CH2 H OH N C HC
NH2
Adenine
Ribose
Phosphate groups - CH

8. The Structure and Hydrolysis of ATP
Energy is released from ATP when the terminal phosphate bond is broken P
Adenosine triphosphate (ATP)
H2O +
Energy
Inorganic phosphate
Adenosine diphosphate (ADP)
P i

9. Cellular Work A cell does three main kinds of work Mechanical
Transport
Chemical
Energy coupling is a key feature in the way cells manage their energy resources to do this work
ATP powers cellular work by coupling catabolic reactions to anabolic reactions

10. How ATP Performs Work ATP + Glu ADP Solute NH2 NH3 P i P Motor protein
(c) Chemical work: ATP phosphorylates key reactants P
Membrane
protein
Motor protein
P i
Protein moved
(a) Mechanical work: ATP phosphorylates motor proteins
ATP
(b) Transport work: ATP phosphorylates transport proteins
Solute
transported
Glu
NH3
NH2 +
Reactants: Glutamic acid
and ammonia
Product (glutamine)
made
ADP

12. GLUCOSE METABOLISM the cornerstone of life
neurons are especially dependent on glucose
regulatory mechanisms:
hyperglycemic hormones = glycogenolysis, gluconeogenesis
hypoglycemic hormone = insulin

14. Protein Metabolism
Deamination: removal of the amino group (NH2) leaving a acetyl molecule
Transamination: Adding an animo group to pyruvic acid to produce any of the nonessential amino acids
Protein Synthesis: Production of protein molecule using an RNA model.
Protein catabolism: breaking down a protein into individual Amino Acids.

15. Lipid Metabolism
Lipoproteins: surrounding triglycerides with apoproteins to make them more transportable in water
Very low-density lipoproteins (VLDL’s)
Low-density lipoproteins (LDL’s)
High-density lipoprteins (HDL’s)
Lipolysis: break down lipids
Beta Oxidation: breaking a fatty acid into 2 carbon compounds
Lipogenesis: formation of lipids from non-lipids