photosynthesis and cellular respiration

• Photosynthesis


  The process by which plants, algae, and some bacteria convert light energy to chemical energy in the form of sugars
• Photoautotroph


  An organism that produces its own food using light energy (like plants)
• ATP

  Adenosine triphosphate, the primary energy carrier in living things
• Chloroplast


  The plant cell structure where photosynthesis occurs
• Thylakoids


  Disc-like structures within a chloroplast that help absorb light
• Grana


  Stacks of thylakoids in a chloroplast
• Chlorophyll


  A pigment found in the thylakoid that absorbs light energy and uses it to produce carbohydrates
• Stroma


  Fluid-filled space surrounding the grana
• Photosynthesis reaction

  Photoautotrophs use energy from the sun, along with carbon dioxide and water, to form glucose and oxygen
• Stages of photosynthesis

  • Light-dependent reactions
  • Calvin cycle
• Light-dependent reactions


  • Light energy is captured by chloroplasts and stored as ATP
• Calvin cycle


  • ATP is used to create sugars that the plant will use to grow and live
• Photosynthesis and cellular respiration are almost opposite processes
• Plants are green because chlorophyll reflects green light
• Light-dependent reactions


  1. Receive light

  2. Provide energy for the Calvin cycle

  3. Molecules go back to the thylakoids to be reenergized
• Light-dependent reactions


  Provide energy for the Calvin cycle
• The Calvin cycle is dependent on the light-dependent reactions
• Photosynthesis is a light-dependent process
• During the night, no oxygen, ATP, or NADPH is being made because a source of light energy is not available
• Plants still have enough energy to survive during the night due to cellular respiration
• ATP

  A nucleotide, not sugar
• Calvin cycle


  1. ATP and NADPH are broken down into ADP, Pi, and NADP+

  2. Used-up molecules react to bind together into ATP and NADPH again
• The carbon atoms needed to build sugar molecules are taken from the CO2 that the plant absorbs
• CO2 is converted into glucose during the Calvin cycle, which is an anabolic pathway and therefore needs ATP to actually build up the molecules
• Every time the process of photosynthesis happens, it produces 1 molecule of oxygen along with the ATP and NADPH
• Only one molecule of oxygen is hardly anything compared to actual air space, much more must be produced to actually make a difference
• Photosynthesis continues producing a larger quantity of oxygen
• Cellular respiration


  The process by which organisms break down glucose into a form that the cell can use as energy
• ATP

  Adenosine triphosphate, the primary energy carrier in living things
• Mitochondria


  The eukaryotic cell structure where cellular respiration occurs
• Cytoplasm

  The contents of a cell between the plasma membrane and the nuclear envelope; includes cytosol which is the jelly-like substance that fills the space between organelles
• Aerobic


  Process that requires oxygen
• Anaerobic


  Process that does not require oxygen
• Fermentation


  An anaerobic pathway for breaking down glucose
• Aerobic cellular respiration

  1. Glucose reacts with oxygen, forming ATP that can be used by the cell

  2. Carbon dioxide and water are created as byproducts
• Stages of aerobic cellular respiration

  1. Glycolysis (an anaerobic process)

  2. The Krebs cycle

  3. Oxidative phosphorylation
• Fermentation

  Glycolysis, followed by the anaerobic process of fermentation to make ATP
• Lactic acid fermentation


  Muscle cells can continue to produce ATP when oxygen runs low
• Alcoholic fermentation


  Many yeast use this to produce ethanol
• Glycolysis

  1. Breaks down glucose

  2. Produces two pyruvate molecules

  3. Produces ATP

  4. Reduces NAD+ to NADH