ATP: The Fuel of Life Cellular respiration produces ATP, the fuel of life. C 6 H 12 O 6 + 6O 2 -> 6CO 2 + 6H 2 O + ATP Cellular respiration can be broken down into three parts: Glycolysis The Krebs Cycle (Citric Acid Cycle) Electron Transport Chain

Glycolysis Glycolysis occurs in the cytoplasm. It needs two molecules of ATP to begin, and results in a net gain of two molecules of ATP. Glycolysis begins with a six-carbon sugar, and produces pyruvic acid in addition to ATP.

The Krebs Cycle The chemical bonds in pyruvic acid are broken in a series of reactions known as the Krebs cycle. The Krebs cycle takes place in the mitochondria. The cycle produces 2 molecules of carbon dioxide, and 1 molecule of ATP. For each glucose molecules, the cycle takes place twice.

Electron Transport Chain The electron transport chain occurs in the inner membrane of the mitochondria. NAD+ and FAD take the high energy electrons from Kreb cycle to the inner membrane of the mitochondria. The high energy electrons are then passed from various molecules in the electron transport chain: cytochromes. The energy of these electrons is used to produce ATP. The electron transport chain produces 32 or 36 ATP molecules, depending on the electron carrier. OXYGEN is the final recipient of the electrons

Fermentation Cellular respiration requires oxygen. When oxygen is not present, fermentation occurs. There are two types of fermentation: lactic acid fermentation and alcoholic fermentation. In lactic acid fermentation, pyruvic acid is converted into lactic acid. Lactic acid is produced in the muscles. This is what makes muscles “sore” after exercise In alcoholic fermentation, pyruvic acid is broken down to produce alcohol and carbon dioxide. This is how whiskey and other alcohols are produced

Photosynthesis

The Process of Photosynthesis Photosynthesis is the process by which green plants use the energy in sunlight to produce carbohydrates. Plants contain pigments. Pigments are colored substances that reflect or absorb light. One such pigment is chlorophyll. When chlorophyll absorbs light, much of that light energy is transferred to electrons in the chlorophyll molecule.

Light-Dependent Reactions Light-dependent reactions require direct involvement of light. They use SUNLIGHT to excite electrons. These excited electrons move to an electron acceptor. At the end of the light-dependent reaction, ATP and NADP+ are produced.

Light-Independent (Calvin Cycle) Reactions Light-independent reactions use the energy from ATP to make sugars. Water is split. (Hydrogen is needed) Carbon (from CO2) is used for the Carbon molecules needed in a sugar Each turn of the Calvin cycle uses 1 molecule of carbon dioxide and 2 atoms of hydrogen. The products of the light-independent reaction are simple sugars.

Plant Cells

Cell Wall Chlorophyl

Stomata Guard cells

Photorespiration RuBisCo fixes Oxygen Wastefull Evolutionary left over

Cam Plants Stomata open at NIGHT CO2 stored as organic acids in the vacuoles CO2 focused around RuBisCo by TIME

C4 Plants Uses PEP to fix CO2 in mesophyll cells and move it to Bundle Sheath cells (as Malate) Focus CO2 around RuBisCo SPATIALLY Very little O2 in the bundle sheath