Photosynthesis

• Photosynthesis

  • Photosynthesis is an endergonic reaction
• • Photosynthesis
  • Autotrophic Process: Plants and plant-like organisms make their energy (glucose) from sunlight which is stored as carbohydrate in their bodies.
• “Photo-synthesis”= putting together with light
• Plants use glucose as food for energy and as a building block for growing. Autotrophs make glucose and heterotrophs are consumers of it.
• Leaves are green because they contain the pigment: chlorophyll
• Stomata are the tiny openings present on the epidermis of leave, CO2 in and O2 out, gas exchange.
• Chloroplasts

  –Organelles in plant and algae cells where photosynthesis occurs.
• Nicotinamide adenine dinucleotide phosphate

  –A molecule used in both light-dependent and light-independent reactions to reduce carbon dioxide to form monosaccharides (glucose)
• Adenosine diphosphate (ADP)

  –Molecules converted into ATP which is the source of energy for cellular metabolism
• NADP+

  –An electron carrier in cellular respiration
• Light Dependent Reaction

   The light reaction is the first stage of the photosynthesis process in which solar energy is converted into chemical energy in the form of ATP and NADPH. The three products of the light reaction of photosynthesis are ATP, NADPH, and O2.
• Light Independent Reaction.

  • This phase is also called the Calvin-Benson Cycle.
• Light Independent Reaction

  • They take place during day and night because they do not

  require the presence of light.
• Light Independent Reaction

  This is the stage when cells take inorganic carbon from carbon dioxide and combine it with organic molecules.
• Light Dependent Reaction

  Occurs in in thylakoids
• • The Light Reactions (Phase 1) capture the energy in sunlightand convert it to chemical energy in the form of ATP and NADPH through the use of photosystems, electron transport chains, and chemiosmosis.
• • The Calvin Cycle (Phase 2) uses the energy transformed by the light reactions along with carbon dioxide to produce organic compounds.
• The organic compound ultimately produced during the Calvin Cycle, glucose
• In the Calvin Cycle, energy and electrons from the

  Light Reactions (in the form of ATP and NADPH) and carbon dioxide from the atmosphere are used to produce organic compounds.
• The Calvin Cycle occurs in the stroma inside the chloroplast inside the cells
• Calvin Cycle

  • Carbon dioxide, ATP, and NADPH are required

  (reactants).

  • Organic compounds (G3P) are produced (products)
• There are two energy pathways for cellular respiration among animals: aerobic pathway and the anaerobic pathway.

  •
• Oxygen has a role to play in the aerobic pathway
• No or little oxygen is needed in the anaerobic pathway.
• Aerobic Pathway. Cells produce energy in the presence of oxygen. This metabolism is called Cellular respiration.
• Anaerobic Pathway. Cells undergo a series of metabolic reactions with little or no oxygen present. It is also the energy pathway for cells that do not contain mitochondria.
• •The aerobic pathway has three (3) stages.

  1. Glycolysis

  2. Krebs Cycle

  3. Electron transport chain (ETC)
• Krebs Cycle also known as Citric Acid Cycle
• Glycolysis is referred to as a “ten enzyme-catalyzed reaction"
• • The anaerobic pathway has two (2) stages.

  1. Glycolysis

    2. Fermentation
• Lactic Acid Fermentation

  Used by animals and certain bacteria. The by-product is lactic acid and NAD+.
• Alcohol Fermentation

  Microorganisms like yeast take the alcohol fermentation pathway to harvest energy. The by-product of this reaction is ethyl alcohol and NAD+