Photosynthesis and Cellular Respiration Overview

Photosynthesis and Cellular Respiration Relationship

• Photosynthesis and cellular respiration are linked; the products of one are reactants for the other.
• Photosynthesis is an anabolic process.
• Cellular respiration is a catabolic process.

Photosynthesis Formula

• 6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂

Cellular Respiration Formula

• C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)

ATP Energy

• ATP = Adenosine Triphosphate
• Glucose is a high-energy carbohydrate.
• ATP is a high-energy molecule that stores and releases energy for cellular processes.
• The release of the last phosphate group of ATP and the formation of ADP + Pi forms a usable energy source.

ATP-ADP Process

(Diagram description is required to fill this in.)

ATP Uses

• Transport across membranes against a concentration gradient
• Organelle movement in the cytoplasm
• Endocytosis/Exocytosis
• Building new molecules
• Muscle protein movement
• Maintaining body temperature

Metabolic Pathways

• Metabolic pathways are series of interconnected chemical reactions.
• Enzymes are protein catalysts that speed up chemical reactions.
• Metabolism encompasses all chemical reactions in a living organism.

Anabolic vs. Catabolic Pathways

• Anabolic pathways build complex molecules (e.g., photosynthesis).
• Catabolic pathways break down complex molecules (e.g., cellular respiration).

Redox Reactions

• Redox reactions involve oxidation and reduction.
• Oxidation is the loss of electrons.
• Reduction is the gain of electrons.
• All matter has oxidation states.

Photosynthesis Examples

• Oxidation of carbon dioxide to form glucose.

Cellular Respiration Example

• Oxidation of glucose to form carbon dioxide.

The Chloroplast

• Each photosynthetic cell contains numerous chloroplasts.

Chloroplast Structure

• Thylakoids: sac-like membranes within the chloroplast; sites for light-dependent reactions.
• Thylakoid membrane contains pigment clusters.
• Thylakoid lumen: space inside the thylakoid.
• Grana: stacks of thylakoids.
• Stroma: fluid-filled space surrounding the thylakoids; site of the Calvin Cycle.

Pigments

• Pigments are arranged in photosystems within the thylakoid membranes, necessary for photosynthesis.
• Chlorophyll is the primary pigment in most photosynthetic organisms; others can supplement it, and aid in capturing wavelengths of light.

Light Absorption and Photosynthesis

• Spectrophotometer charts show the light absorption wavelengths of pigments in the spectrum or light to show the absorption spectrum.
• An action spectrum shows the rate of photosynthesis at different wavelengths of light.

Photosynthesis Overview

• Light-dependent reactions :capture light energy to produce ATP and NADPH (reduced NADP+).
• Light-independent reactions (Calvin Cycle) :use ATP and NADPH to assemble sugars.

Light-Dependent Reactions

• Photosystem II (PSII): The first light-dependent process, where light excites chlorophylls, splits water molecules to release oxygen, and generates high-energy electrons.
• Electron Transport Chain (ETC): A series of carriers that move electrons, releasing energy for ATP production.
• Photosystem I (PSI): Light energizes electrons again, reducing NADP⁺ to NADPH..
• ATP Synthase:Uses the proton gradient formed by the ETC to produce ATP.

Light-Independent Reactions/Calvin Cycle

• Carbon fixation: CO₂ is attached to RuBP.
• Reduction: ATP and NADPH reduce three-carbon molecules (G3P).
• Regeneration: some G3P molecules are rearranged to regenerate RuBP.
• Glucose formation- Glucose is created from several reactions.

Overall:

• Photosynthesis turns light energy into chemical energy in the form of glucose using water and carbon dioxide as a source of electrons. During cellular respiration, glucose is broken down to release the stored energy as ATP, a readily available source for cell processes.