Energy, ATP, and Cellular Respiration Notes

Energy, ATP and Cellular Respiration

Forms of Energy

• Energy: The capacity to do work.
• Potential Energy: Stored energy.
• Kinetic Energy: Energy in use.
• Forms of energy
  • Chemical.
  • Mechanical.
  • Electrical.
  • Radiant (heat and light).
  • Gravitational.
  • Nuclear.

Chemical Potential Energy

• Energy stored in substances such as petrol, wood, batteries, carbohydrates, and fats.

Nuclear Potential Energy

• The energy stored in the nucleus of every atom.

Kinetic Forms of Energy

• Electricity: A current of moving electrons.
• Sound energy

Radiant Kinetic Energy

• Includes heat, light, radio waves, microwaves, x-rays, and gamma (γ) rays.

Energy Transformations

• Energy cannot be created nor destroyed, but it can be converted from one form to another.
• Appliances are energy converters.

Energy Conversions Examples

• Potential chemical energy from food (carbohydrates, fats) is converted to:
  • Mechanical energy (moving muscles).
  • Electrical energy (to form nerve impulses).
  • Chemical energy (stored in new compounds).
  • Heat energy (to keep warm).
  • Sound energy.

Energy Conversions in Chemical Reactions

• All chemical compounds contain stored energy.
• Exothermic reactions: Result in a release of energy.
  • reactants → products + ENERGY
• Endothermic reactions: Result in an absorption of energy.
  • reactants + ENERGY → products

Photosynthesis

• Plants convert radiant energy from the sun into potential chemical energy (stored in the bonds within glucose molecules) using photosynthesis.
• 6 CO2 + 6 H2O + sunlight (energy) → C6H{12}O6 + 6 O2
• Photosynthesis is an endothermic reaction.

Oxidation of Glucose in Cells

• Releases the energy stored in a glucose molecule for cellular work.
• C6H{12}O6 + 6O2 → 6CO2 + 6H2O + Energy
• This reaction is exothermic.

Aerobic Cell Respiration

• C6H{12}O6 + 6 O2 → 6 CO2 + 6 H2O + energy released
• Cell respiration is the biochemical pathway that animals, plants, and most bacteria use to release the energy stored in food molecules for cellular work.
• Reactions that release energy are exothermic.
• The energy released is transferred to ATP molecules for temporary storage in cells.

Uses of ATP in Cells

• Cells continuously require large amounts of energy for essential cellular processes.
  • Protein synthesis.
  • Cell secretion.
  • Digesting unwanted debris in cells.
  • Active transport.

Uses of ATP in the Body

• Moving cilia.
• Muscle movement.
• Flagellum movement.

ATP: Temporary Energy Storage

• Energy in from cellular respiration fuels ATP synthesis.
• Energy from ATP is used for cellular work.

Aerobic Cellular Respiration Details

• Occurs in the presence of oxygen.
• Glycolysis occurs in the cytoplasm, producing 2 ATP and pyruvic acid.
• Pyruvic acid enters the mitochondrion, where the citric acid cycle and electron transport chain occur.
• The electron transport chain produces approximately 32 ATP.
• Total ATP production: 36 ATP per glucose molecule.

Anaerobic Cellular Respiration Details

• Occurs in the absence of oxygen.
• Glycolysis occurs in the cytoplasm, producing 2 ATP and pyruvic acid.
• Pyruvic acid is converted to lactic acid.
• Net ATP production: 2 ATP per glucose molecule.