Photosynthesis and Cellular Respiration

Chap.6&7

Final points on photosynthesis

• It is done by autotrophs. (plants) • It starts with light reactions that occur in

photosystem one and two in which sunlight is captured, absorbed, synthesized into ATP through the process of chemiosis. (chloroplast)

• Then the Calvin cycle fixates carbon. ( breaks CO2 apart so it can be made into sugar)

• At night, plants break down the stored sugar for energy by cellular respiration. (mitochondria)

Relationship between photosynthesis and Cellular Respiration

• cellular respiration is essentially the reverse reaction of photosynthesis. • The formula for photosynthesis is

6 H2O + 6 CO2 + light energy ----------> C6 H12 O6 + 6 O2

and the formula for cellular respiration is

C6 H12 O6 + 6 02 ----------> 6 H2O+ 6 CO2+ energy • From the formulas here, you can see that the products of photosynthesis

fuel cellular respiration and the products of cellular respiration fuel photosynthesis.

• Photosynthesis uses energy from sunlight to build glucose and release oxygen from carbon dioxide and water. Cellular respiration combines oxygen with glucose in the mitochondria to produce ATP; water (along with a little heat) and carbon dioxide are produced as well.

• (wikipedia.com)

Cellular Respiration

• Done by autotrophs and heterotrophs.• Makes ATP. Some ATP is used by the cell to

function.• Is a continuous cycle in heterotrophs but

happens only at night in autotrophs.

Stages of Cellular Respiration

• Begins with glycolysis (breaking down of glucose into smaller carbon chains) in the cytoplasm of a cell.

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Anaerobic Respiration

• If no O2 is present then two types of fermentation can occur:

Lactic Acid fermentation (animal cells)Alcoholic fermentation (yeast and plant cells)

Lactic Acid Fermentation• Causes muscle soreness or cramps.

Alcoholic Fermentation

• No O2 is used to make this:

Krebs Cycle

Aerobic Respiration

• - If O2 is present - Aerobic respiration takes place during the Krebs cycle. This is done in the “power house” of the cell known as the mitochondrion.