Releasing Energy

Releasing Energy

1. Energy released depends on conditions under which the chemical changes take place.

   • Respiration
     • Anaerobic
       • Glucose = lactic acid (+energy available for cells to use
     • Aerobic
       • Glucose + Oxygen = carbon dioxide + water (+ energy available for cells to use)
     • Energy is made available for cells to use in the form of ATP (adenosine triphosphate)
       • KEY DEFINITION: A molecule of ATP is formed when three phosphate groups are attached to an adenosine molecule. Energy is required to attach the phosphates (esp. the 3rd). Respiration provides this energy. ATP is produced during respiration and when the ATP is broken down (ATP to ADP) the energy is released. ATP is used as a means to transfer energy from one process to another.
   • Glucose
     • Comes from food eaten
   • Oxygen
     • Comes from air breathed in

2. The circulatory system and the respiratory systems work together

   • Biochemical changes for anaerobic respiration takes place in the cytoplasm where there are enzymes that promote these reactions.
   • Biochemical changes for aerobic respiration take place in the mitochondria
   • Most respiring cells in the body are away from the gut/lungs
     • Wastes have to be excreted
       • The circulatory system delivers oxygen to respiring cells and takes carbon dioxide away from the cell to be released in the lungs
         • Also transports the energy released as heat or in chemical form to parts of the body that need it

3. Why is respiration so important?

   • MRS NERG - Growth, sensitivity, nutrition, movement, excretion and reproduction all require energy to make chemical changes.
   • Respiration provides energy in the form of ATP
     • Breaks down into ADP and in turn AMP (adenosine monophosphate), so that the phosphate groups may be transferred to other molecules to make them more reactive and making chemical change more likely.
       • Example, ATP provides energy for chemical change in the eye retina making visual pigments.
       • One form of AMP is a messenger in the body. Cyclic AMP activates enzymes to make chemical changes more likely.
         • Hormone triggers the production of cyclic AMP which activates the enzymes associated with that hormone. As a result hormones control changes that happen in the body.
   • Energy for: Muscle -contraction, -nerve impulse -transmission, -separation of chromosomes in nuclear divison, -active transport and uptake of ions