Energy and ATP, Photosynthesis and Cellular Respiration

Energy and ATP

Energy All living things use energy. Energy for life’s activities is stored in bonds of energy-storing compounds: ATP, NADH, DADPH, FADH 2 ATP is the chief energy-storing molecule used by organisms.

ATP Adenosine triphosphate = ATP AdenineRibosePhosphates (3 of them) Adenosine

ATP Adenosine triphosphate = ATP The ATP molecules releases energy when a bond holding a phosphate group to the molecule is broken

ATP Adenosine triphosphate = ATP ADP = adenosine diphosphate (di means 2) + + energy

ATP Cycle

Food Sources Autotrophs - make own food Ex. Photoautotrophs - make own food using light energy (photosynthesis) Heterotrophs - cannot make own food; depend on autotrophs or other heterotrophs

Photosynthesis

Photosynthesis - process by which autotrophs convert sunlight to usable energy

Pigments Autotrophs that perform photosynthesis contain chemicals called pigments. A pigment is a molecule that absorbs certain wavelengths of light and reflects others. We see what is reflected.

Chlorophyll The most common and important pigment for photosynthesis is chlorophyll. Chlorophyll reflects green light, but absorbs others like violet, blue, and red. Plants look green because of this! The absorbed light is the energy source for photosynthesis.

Chloroplast The chlorophyll and other pigments are typically located in the specialized organelles called chloroplasts.

Chloroplast Structure Outer membrane and Inner membrane StromaThylakoids Grana Chloroplast

Chloroplast Structure The individual disk-shaped structures are called the thylakoids. Inside is called the thylakoid space, which contains the chlorophyll, which is arranged in units called photosystems to collect light. Each stack of thylakoids is called a granum. All of the stacks together is the grana. The gel-like material surrounding the grana is the stroma.

Photosynthesis The process is divided into 2 parts: The light-dependent reactions The Calvin cycle

Light-Dependent Reactions Occur in the thylakoids Requires sunlight and water A water molecule is split H 2 O  O 2 (oxygen), H + (hydrogen ions), and energized electrons. The oxygen diffuses out. The hydrogen ions and electrons are involved in making ATP and turning NADP + into NADPH, energy-storing compounds.

Light-Dependent Reactions

Calvin cycle Occurs in the stroma Requires products of light rxns and the input of CO 2 One molecule of glucose (C 6 H 12 O 6 ) is created from every 6 CO 2 molecules.

C 6 H 12 O 6

The Equation The reactants: Carbon dioxide (CO 2 ) Water (H 2 O) Energy - light The products: Glucose (C 6 H 12 O 6 ) Oxygen (O 2 ) The reactants are input for photosynthesis and re-arranged to form the products.

The Equation The balanced equation: 6CO 2 + 6H 2 O + energy  C 6 H 12 O 6 + 6O 2

Reactants and Products