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