• Lipids (fats)

• Carbohydrates (sugar)

• Protein

ENERGY• 1st Law of Thermodynamics

– Energy can’t be created or destroyed, it can only change forms.

chemical→ mechanical

chemical → mechanical

heat → mechanical electrical → mechanical

Photosynthesis

6 CO2 + 6H2O + energy→ C6H12O6 + 6O2

Metabolism

• Metabolism = The sum of all reactions occurring in an organism

– Catabolism – reactions involved in the breakdown of biomolecules; release heat/energy

– Anabolism – reactions involved in the synthesis of biomolecules; absorb heat/energy

.

ANABOLIC

CATABOLIC

Metabolism– Metabolism is the sum of catabolism and

anabolism.

oxidation and the release of energy

Triglycerides Proteins

Fatty acidsand glycerol

Amino Acids

Small molecules

Anabolismof proteins

beakdown of larger molecules to smaller ones

Some nutrients and products of catabolism

Products of anabolism, including proteins and

nucleic acids

Catabolism Excretion

energy andreducing agents

Monosac-charides

Polysac-charides

ExcretionAnabolism

Catabolism Anabolism

Free Energy (G)

A + B → C

A + B

C

Fre

e En

ergy

(G)

5

10

If A + B has more free energy than C, then the change in free energy (G) is negative. Product (C) – Reactants (A + B) 5-10 = -5

If energy is given off in a reaction; G is negative; favorable; catabolic

A + B → C

C

A + B

Fre

e En

ergy

(G)

5

10

If A + B has less free energy than C, then the change in free energy (G) is positive. Product (C) – Reactants (A + B) 10-5 = +5

If energy is absorbed in a reaction; G is positive; unfavorable; anabolic

6 CO2 + 6H2O + energy→ C6H12O6 + 6O2

PHOTOSYNTHESIS

G = +686 kcal energy

Free E

nergy (G

)

6 CO2 + 6 H2O

C6H12O6 + 6 O2

686

CATABOLISM OF FOOD

ATP = Adenosine Triphosphate

(G)Products – (G)Reactants = G [ADP + P] - ATP G = -7.3 kcal

Fre

e En

ergy

(G)

ATP

ADP + P

7.3 kcal

ATP → ADP + P

ATP → ADP + P + energy

7.3 kcal7.3 kcal

ADP + P + energy → ATP

Energy is given off;G is negative

Energy is absorbed; G is positive

MITOCHONDRIA

Metabolism = The sum of all reactions occurring in an organism

• Goal is to couple reactions that give off energy with those that absorb energy

A + B → AB

AB is higher energy than A and B alone

G is positive; requires input of energy; unfavorable

ADP and P are lower energy than ATPG is negative; releases energy; favorable

ATP → ADP + P

Coupled Reactions

ATP → ADP + P

A + B → AB G = +4.3 kcal

G = -7.3 kcal

A + B + ATP → AB + ADP + P

Overall G for coupled reaction = -3.0 kcal

Coupled reaction would be FAVORABLE

G =-3.0