2.8 Cell Respiration Flashcards
Cell respiration
the controlled release of energy from organic compounds to produce ATP.
cell respiration formula
C6H12O6 + 6O2 —–> 6CO2 + 6H2O
glucose + oxygen —–> carbon dioxide and water
ATP stands for
adenosine triphosphate
ATP cannot leave the cell, so…
every cell must make their own supply
heat energy in ATP
ATP used in cells creates heat that can keep organism warm but this is lost to environment so ATP must be continus supply
ATP is needed for
- synthesizing large molecules like DNA, RNA and proteins
- pumping molecules or ions across membranes by active transport
- moving thinhgs around inside the cell or for muscle contractions
When ATP is hydrolysed (to form ADP + Pi)….
the energy stored in the phophate bond is released to be used by the cell
Cell respiration uses energy stored in organic molecules to ….
regenerate ATP from ADP + Pi (via oxidation)
Glycolysis
1st stage for both types of respiration.
Location: Cytoplasm of the cell.
Glucose molecules are broken down into pyruvate molecules with the release of a small amount of energy (2 ATP).
Aerobic cell respiration
Pyruvate from glycolysis moves to the Mitochondria.
Inside the mitochondria the pyruvate is broken down into carbon dioxide and water.
A large amount of ATP is produced (about 36 ATP).
- The water can be useful – some desert animals never need to drink as respiration provides all the water they need!
Anaerobic cell respiration
When O2 is not available, anaerobic respiration may occur.
In the absence of oxygen, glucose can only be partially broken down, there will be less energy available to the cell.
Pyruvate must be broken down somehow for cell respiration to continue
The name given to these anaerobic processes is Fermentation.
Alcohol fermentation:
Which occurs in plants and yeasts.
pyruvate —-> ethanol + carbon dioxide
Lactate fermentation:
Which occurs in animals.
pyruvate —-> lactate (lactic acid)
electron carrier, NAD+ is regenerated…
the cycle can continue in the absence of oxygen, allows glycolysis and fermentation to continue, producing only 2 ATP each time (from glycolysis).
uses of alcohol fermentation
Bread – Carbon dioxide causes dough to rise (leavening), the ethanol evaporates during baking
bioethanol- ethanol produced from yeasts is used as fuel in vehicles