The chemical reactions inside cells are controlled by enzymes.
Respiration: process where o2 reacts w/ glucose + releases energy
All living organisms obtain energy via respiration to fuel their metabolic pathway.
All respire continuously. Respiration occurs in the mitochondria of cells.
Energy released in respiration is used to:
- build larger molecules from smaller ones
- allow muscles to contract, breathing
- maintain a steady body temp (mammals, birds)
- build sugars + nitrates into amino acids (plants)
Aerobic& anaerobic respiration
Aerobic respiration is with oxygen.
Glucose + oxygen --------> carbon dioxide + water + energy (32 ATP)
C6H12O6 ------> CO2 + H2O + 32 ATP
Releases energy through breakdown of glucose molecules.
Anaerobic respiration is without oxygen.
If insufficient oxygen is reaching the muscles then cells use anaerobic respiration to obtain energy.
It is the incomplete breakdown of glucose + produces lactic acid.
The lactic acide lowers the pH inside/around cells, causing enzymes to denature. Can cause muscle fatigue / cramps. blood flowing through muscle rids lactic acid.
Animals: Glucose ---------> lactic acid + energy (2 ATP)
Plants: Glucose ------------> ethanol + co2 + energy
Less efficient than aerobic. Anaerobic results in an oxygen debt. Has to be repaid to oxidise lactic acid ---> co2 + h2o
-heart rate increases
muscles require more oxygen + glucose ----> pump faster, arrive faster.
-breathing rate&depth increases
body needs more oxygen.
as body temp rises during exercise. when sweat (h2o) evaporates, takes heat w/ it.
body temp - too high enzymes denature.
-blood vessels vasodilate
so diffusion can take place more quickly