Chapter 9: Cellular Respiration
Energy in a substanceEnergy in a substance::
Measured by how muchMeasured by how much heatheat it it releasesreleases
Energy is measured in Energy is measured in caloriescalories
One calorie heats one gram of One calorie heats one gram of water one degree Celsius water one degree Celsius
Food energy is measured in Food energy is measured in CaloriesCalories– One Calorie = 1 kilocalorie (1000 One Calorie = 1 kilocalorie (1000
calories)calories)
Cells release the energy in glucose Cells release the energy in glucose to make to make ATPATP molecules molecules
Adenine Ribose 3 Phosphate groups
ATP Molecule
What would ADP look like?
The breakdown of glucose to produce energy in the form of ATP is called Cellular Respiration.
Occurs in the mitochondria of alleukaryotic cells (plant & animal)
Equation for Aerobic cellular respiration:
6O2 + C6H12O6 → 6CO2 + 6H2O + energy (reactants) (products)
Oxygen + glucose → carbon dioxide + water + energy
Cellular respiration begins with glycolysis, breaks glucose into 2 smaller molecules (pyruvate & makes 2 ATP’s)
These 2 ATP’s are burned to make many more later.
After glycolysis, what happens next depends on whether or not oxygen is present.
If oxygen is present…
It is called Aerobic Cellular Respiration, which consists of:
A total of 36 ATP’s = a lot!
Anaerobic Cellular Respiration-“Fermentation”
If no oxygen is present, cells make ATP energy through this process. The ATP total is only 2, compared to 36 for
aerobic respiration.
There are two types of fermentation that begin with glycolysis, but occur in
different types of organisms.
Alcoholic FermentationOccur in yeasts and microorganisms
Produces ethanol (alcohol, what we drink in alcoholic beverages), carbon dioxide, and 2 ATP’s.
Important to the alcoholic beverage industry and to the baking industry
The CO2 makes the bubbles in beer or air spaces in rising bread
Lactic Acid Fermentation
Occurs in animal muscle cells.
Happens when animals become breathless, especially during physical activity (exercise).
Causes muscle cramps and sore muscles.
Products: lactic acid & 2 ATP’s
Slowing down and catching your breath switches you back to aerobic
respiration.
Don’t exercise to the point of breathlessness!
Some bacteria that go through lactic acid fermentation are used in the food and beverage industry
Cheese, yogurt, buttermilk, sour cream, pickles, sauerkraut
Anaerobic Cellular Respiration Anaerobic Cellular Respiration Comparison:Comparison:
Yeast cellsYeast cells Either of these Either of these forms produces forms produces only 2 ATPs.only 2 ATPs.
Animal Animal muscle cellsmuscle cells
Produces Produces alcohol, CO2alcohol, CO2
Isn’t much, and Isn’t much, and its better for cells its better for cells
to run aerobic to run aerobic respiration.respiration.
Produces Produces lactic acid lactic acid (muscle (muscle
soreness)soreness)
Alcoholic In common Lactic acid
Comparing photosynthesis and Comparing photosynthesis and respirationrespiration
Photosynthesis and respiration are Photosynthesis and respiration are oppositeopposite processes processes
Photosynthesis Photosynthesis removesremoves carbon carbon dioxide from airdioxide from airCellular respiration puts it Cellular respiration puts it backbackPhotosynthesis Photosynthesis puts puts oxygen into airoxygen into airRespiration Respiration removesremoves it itPhotosynthesis Photosynthesis capturescaptures energy and energy and converts it into glucoseconverts it into glucoseRespiration Respiration releasesreleases the energy the energy from glucosefrom glucose