Chapter 2 | Cell Chemistry and Bioenergetics

Major biomolecules

• Proteins

• Carbohydrates

• Lipids

• Nucleic acids

• Water

Metabolism

Overall process by which a cell/biological unit acquires & uses free energy to carry out various functions

Catabolism

Breakdown of large molecules into smaller ones: Release free energy; Form building blocks

Anabolism

Buildup of smaller molecules into larger ones

Free energy

Energy capable of doing work

Energy Conservation law

Energy conservation in the universe - can be converted from one form to another

Law of Entropy

Always increases over time in closed system (universe) Heat is the most disordered form of energy

Exergonic

(-) ΔG

Endergonic

(+) ΔG

ATP

Activated carrier molecule/carrier of energy/intermediate, adds free energy to a molecule

Coupling reactions with ATP

• Activation of the intermediate

• Increase free energy -> high energy intermediate by adding a phosphate

• Release of inorganic phosphate (activated carrier), releases energy

Substrate-level phosphorylation

The synthesis of ATP from the direct transfer of a phosphate group from a phosphorylated molecule onto ADP

Other activated carriers of energy

• Phosphate carriers: CTP, UTP, GTP

• Electron carriers: NADH, FADH2, NADPH

Enzymes

• Accelerate a chemical reaction to its equilibrium

• Lower activation energy

• Binds to & reacts with substrate