Photosynthesis and Cellular Respiration Chapter 8 and 9

Topics Big questions – Three topics in this unit ATP How do you make energy? How do plants make food? Three topics in this unit ATP Cellular Respiration Photosynthesis

ATP Energy currency of the cell Adenosine Triphosphate = Adenine and three phosphates

ATP ATP holds energy between the phosphate bonds How do you get the energy out of ATP?

ATP When we take the phosphate off the molecules becomes ADP – Adenosine diphosphate How do we make ATP?

Cellular Respiration

Cellular Respiration Cellular respiration is the process that cells use to make ATP, or energy So what do we need to make energy? Food – glucose Oxygen – We ALWAYS need oxygen

Cellular Respiration Glucose + Oxygen = Carbon dioxide + Water + Energy

Cellular Respiration Remember: We need oxygen and food to make energy We exhale carbon dioxide

Cellular Respiration So now you know what we are starting with, and what we should end with. What about the process? There are two types of respiration Aerobic – Requires oxygen Anaerobic – does not require oxygen Do you think you make more energy with or without oxygen?

Cellular Respiration There are three steps to cellular respiration Glycolysis Krebs cycle Electron transport chain

Glycolysis Does not require oxygen (anaerobic) In the cytoplasm 1 molecule of glucose + 2 ATP = 4 ATP Net production of 2 ATP (made 4 but used two)

Krebs Cycle Requires oxygen (aerobic) In the mitochondria Produces two more ATP Total of 4 ATP so far…

Electron Transport Chain Requires oxygen (aerobic) Passing of electrons by proteins In the mitochondria, on the inner membrane Makes 34 ATP!!!

Cellular Respiration What happens when we don’t have oxygen? Fermentation! Lactic Acid – happens in animal cells, produces lactic acid Alcoholic Fermentation – happens in yeast cells, produces ethanol and carbon dioxide

Photosynthesis

Photosynthesis Photosynthesis is the process that plants use to turn light energy into food What do plants need? Photosynthesis equation Light + CO2 + H2O O2 + Glucose

Photosynthesis Where is the plant do you think this occurs? Leaves Where in the leaf does this occur? Palisade mesophyll Where in the cell does this occur? Chloroplast

Chlorophyll Chlorophyll is the substance in the leaf that absorbs the light? Why is chlorophyll green? Absorbs all colors except green Reflects the color green

Photosynthesis Light reaction (light dependent) Requires light In the thylakoid Light energy is used to make ATP Dark reaction (light independent) Does not require light In the stoma ATP is used to convert CO2 to sugar

Photosynthesis and Respiration How are photosynthesis and cellular respiration connected? Light + CO2 + H2O O2 + Glucose Glucose +O2 CO2 + H2O + ATP