Photosynthesis

• Autotroph


  An organism that uses energy from light or inorganic chemical reactions to produce complex organic compounds from simple inorganic molecules.
• Heterotroph


  An organism that obtains energy by ingesting and digesting complex organic molecules from other organisms.
• Light energy


  The energy used in photosynthesis to convert simple inorganic molecules into complex organic molecules.
• Photosynthesis


  A two-step process that occurs in the chloroplasts of autotrophs, where light energy is converted into complex organic molecules.
• Visible spectrum


  The range of wavelengths between about 400 nm and 700 nm that can be seen by the human eye.
• Chloroplasts

  Organelles found in autotrophs where photosynthesis takes place. They consist of membranes, lamellae, grana, and stroma.
• Membranes


  Structures within chloroplasts that control the movement of substances and provide a large surface area for photosystems to capture light energy.
• Lamellae


  Structures within chloroplasts that connect grana and contain photosystems, which are responsible for capturing light energy.
• Grana


  Stacks of thylakoids within chloroplasts that contain photosystems and provide a large surface area for capturing light energy.
• Stroma


  The fluid-filled space within chloroplasts where the light-independent stage of photosynthesis occurs and enzymes are present.
• Electromagnetic Spectrum


  The range of all possible frequencies of electromagnetic radiation, with the visible spectrum being the only part visible to the human eye.
• Chlorophyll


  A mixture of different pigments in chloroplasts that absorbs light energy for photosynthesis.
• Porphyrin group


  A group within chlorophyll pigments that absorbs light when hit by photons, causing electrons to become excited.
• Chlorophyll a


  A form of chlorophyll that appears yellow-green and absorbs red light at slightly different wavelengths.
• Chlorophyll b


  An accessory pigment that reflects yellow and orange light but absorbs blue light, assisting in light absorption for photosynthesis.
• Carotenoids

  Accessory pigments, including carotene and xanthophyll, that absorb different wavelengths than chlorophylls and transfer energy to primary pigments.
• Photosynthetic pigments


  Pigments found within the photosystems of the thylakoid membrane, absorbing specific wavelengths of light and reflecting others.
• Primary reaction pigment

  The pigment, such as chlorophyll a, that directly absorbs light energy and initiates the light-dependent stage of photosynthesis.
• Accessory pigments


  Pigments, such as chlorophyll b and carotenoids, that assist in light absorption for photosynthesis but are not directly involved in the light-dependent stage.
• Thylakoid membrane


  The membrane within chloroplasts where photosystems are located and arranged in a funnel shape to absorb specific wavelengths of light.
• Reflected light


  The light that is not absorbed by photosynthetic pigments and is instead reflected, resulting in the colors we see.
• Calvin Cycle


  A series of chemical reactions that occur in the stroma of chloroplasts and result in the production of glucose.
• RuBp


  Ribulose Bisphosphate, a 5-carbon compound involved in the initial step of the Calvin Cycle where carbon dioxide is fixed.
• Rubisco

  Ribulose bisphosphate carboxylase, an enzyme that catalyzes the carboxylation of RuBp, initiating the carbon fixation process in the Calvin Cycle.
• GP


  Glycerate 3-phosphate, a 3-carbon compound produced during the Calvin Cycle as an intermediate product.
• GALP


  Triose Phosphate, another name for Glycerate 3-phosphate, which is used in the production of glucose.
• Carbon fixation

  The process by which carbon dioxide is converted into organic compounds, such as glucose, by an enzyme called Rubisco.
• Amino acids


  Building blocks of proteins that can be produced from the products of the Calvin Cycle.
• Fatty acids


  Molecules that can be synthesized from the products of the Calvin Cycle and used in the production of lipids.
• Regeneration


  The process by which some of the triose phosphate (GALP) produced in the Calvin Cycle is used to regenerate RuBp.
• ATP

  Adenosine triphosphate, a molecule that provides energy for the Calvin Cycle and is used to regenerate RuBp.
• NADP red


  Reduced Nicotinamide adenine dinucleotide phosphate, a molecule that provides reducing power to convert GP to GALP.
• Hexose Sugars


  Six-carbon sugars, such as glucose, that can be produced from the products of the Calvin Cycle.
• Glycerol


  A three-carbon alcohol that can be produced from the products of the Calvin Cycle and used in the production of lipids.
• Stroma


  The fluid-filled space within the chloroplast where the light-independent reaction (Calvin Cycle) takes place.
• Starch


  A complex carbohydrate that is formed from the sugars produced in the Calvin Cycle and serves as a storage form of glucose.
• Melvin Calvin


  The scientist who deduced the steps of the Calvin Cycle in the 1940s-50s.
• Turns of the Calvin Cycle

  The number of complete cycles of the Calvin Cycle required to produce one molecule of glucose is 6.
• Net carbon

  Each turn of the Calvin Cycle produces 1 net carbon that can be removed from the cycle and used in the production of glucose.