Photosynthesis V Cellular Respiration

Adenosine Triphosphate (ATP)

The primary usable energy currency of all living cells, consisting of an adenine base, ribose sugar, and three bonded phosphate groups.

Energy Release in ATP

Breaking the high-energy bond between the second and third phosphate groups releases usable cellular energy, converting ATP into adenosine diphosphate (ADP) and an inorganic phosphate (P_i).

Photosynthesis Purpose

Converts radiant (solar) energy into chemical energy stored in the chemical bonds of glucose.

Location of Photosynthesis

Occurs in the chloroplast of plant cells, algae, and cyanobacteria.

Chemical Equation of Photosynthesis

Balanced formula: $6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$.

Cellular Respiration Purpose

Breaks down chemical energy stored in glucose to produce usable ATP for cellular work.

Location of Cellular Respiration

Begins in the cytoplasm and is completed in the mitochondria.

Aerobic Respiration

Requires oxygen and yields approximately 36 to 38 molecules of ATP per glucose molecule.

Balanced Formula of Cellular Respiration

$C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + ATP$.

Anaerobic Respiration

Occurs without oxygen and produces only 2 ATP molecules per glucose molecule.

Lactic Acid Fermentation

Occurs in animal muscle cells under oxygen debt and produces lactic acid.

Alcoholic Fermentation

Occurs in yeast and some plant cells; produces ethanol and $CO_2$.

Cyclic Relationship between Photosynthesis and Cellular Respiration

The products of photosynthesis ($C_6H_{12}O_6$ and $O_2$) serve as reactants for cellular respiration and vice versa.

Matter in Ecosystems

Carbon, hydrogen, and oxygen cycle continuously between organisms and the atmosphere.

Energy Flow in Ecosystems

Energy flows in a one-way path entering ecosystems as solar energy and exiting primarily as metabolic heat.