Bell work• Get out your iwork and have it

ready to turn in.

• Clear your desk in preparation for the photosynthesis quiz.

Questions• What do you know about cellular

respiration?

• What do you know about how it relates to photosynthesis?

Ch 7 Cellular RespirationExplain cellular respiration and its three stages: glycolysis, Kreb’s cycle and electron transport chain.

Know where each stage of cellular respiration takes place.

Write the chemical equation for cellular respiration and identify the reactants and products.

Distinguish between aerobic and anaerobic respiration.

Describe the two main types of fermentation?

Cellular Respiration• process that releases energy by breaking

down food molecules • Aerobic respiration• requires oxygen• takes place in the mitochondria• converts sugar and oxygen into carbon

dioxide, water, and energy [ATP]• three sets of chemical reactions– glycolysis– Kreb’s cycle– electron transport chain

• Answer the following question using Socrative room number 101428

• A student sets up a sealed ecosystem containing a snail (a consumer) and an elodea (a producer). The balance of gases in the ecosystem remains stable over a period of several days. The student concludes that the gas output of the snail equals the gas intake of the elodea and that the gas input of the snail equals the gas output of the elodea. Which finding would suggest that the student’s conclusion must be re-evaluated due to another consumer accidentally being included in the ecosystem?

A) Oxygen content of air in the ecosystem rises when the snail is removed.

B) Oxygen content of air in the ecosystem falls when the elodea is removed.

C) Carbon dioxide content of air in the ecosystem shows little change when the snail is removed.

D) Carbon dioxide content of air in the ecosystem shows little change when the elodea is removed.

Chemical Equation

C6H12O6 + O2 CO2 + H2O + ATP

glucose + oxygen yields carbon dioxide + water + energy

Glycolysis• process in which one molecule of glucose is

broken in half, producing two molecules of pyruvic acid

• takes place in cytosol of cytoplasm• does not require oxygen• converts glucose, ADP, and NAD+• to pyruvic acid, ATP, and NADH• net production of ATP: 2 ATP

Glycolysis.mov

Kreb’s Cycle• second stage of cellular respiration, in

which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

• takes place in matrix of mitochondrion

• converts pyruvic acid, NAD+, FAD+, and ADP

• to CO2, NADH, FADH2, ATP

• net production of ATP: 2 ATP

Electron Transport Chain

• high-energy electrons from the Krebs cycle are used to convert ADP into ATP

• takes place at inner membrane of the mitochondrion

• converts O2, NADH, FADH2 and ADP

• to H2O, NAD+, FAD+, ATP

• net production of ATP: 32 ATP

Electron Transport Chain

Cellular Respiration

Total: 36 ATP

• Glycolysis– 2 ATP

• Kreb’s Cycle– 2 ATP

• Electron Transport Chain– 32 ATP

Anaerobic Respiration• process by which cells release energy in the

absence of oxygen• also known as fermentation• begins with Glycolysis

• Two types of fermentation– lactic acid fermentation

• animal muscles• pyruvic acid + NADH lactic acid + NAD+

– alcoholic fermentation• Yeasts and a few other microorganisms • forms ethyl alcohol and carbon dioxide as wastes.

• pyruvic acid + NADH alcohol + CO2 + NAD+

Aerobic Respiration Anaerobic Respiration

Cellular respiration Fermentation

requires O2 no O2 required

36 ATP 2 ATP

Glycolysis

Kreb’s Cycle

Electron Transport Chain

Glycolysis

Lactic acid fermentation or

Alcoholic fermentation