Photosynthesis- solar energy is converted into chemical energy because energy is stored in the chemical bonds of glucose
Grana- consisting of layers of membranes called thylakoids (where light dependent reactions occur)
Stroma- where Calvin Cycle (light independent reactions) occur
Stroma- where Calvin Cycle (light independent reactions) occur
Pigments: absorb light energy and use it to carry out photosynthesis
Light Dependent & Light Independent Reactions
Light Dependent reaction: to produce energy (ATP) and protons for the Light Independent Reactions
Light Independent Reactions: to make sugar
Light Independent Reactions: to make sugar
Light Dependent Reaction:
Where: in the grana within the specialized membranes called thylakoids
What: these thylakoids have hundreds of light absorbing pigments (chlorophyll) As chlorophyll absorb light, electrons become energized and escape from chlorophyll molecules into the ETC. |
WATER breaks down, by the process of photolysis, into its components (electrons, protons, and oxygen atoms)
Oxygen: released into the atmosphere as a waste product-- the source of all our oxygen in the atmosphere |
Light Independent Reactions
** Sugar (PGAL) is produced during the Calvin cycle of the light independent reactions
Where: in the STROMA What: CO2, which is taken in from leaves, combines with protons and electrons carried from light reactions by NADP to produce sugar EQUATION: CO2 + H+ (protons) + electrons -> PGAL Carbon dioxide is incorporated into a sugar molecule by means of carbon fixation CALVIN CYCLE: cyclical process where large amount of ATP is required to keep the Calvin cycle running (ATP was produced during the light dependent reactions) |
FACTS about Light Independent Reactions:
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Cellular Respiration
Structure of the Mitochondria
Two membranes
The Krebs Cycle takes place in the matrix The Electron Transport Chain takes place in the cristae membrane RESPIRATION OVERVIEW:
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Glycolysis
- oxygen is not needed for this process - occurs in the cytoplasm - process is controlled by different enzymes - produces 2 pyruvates and only a net of 2 ATP |
Anaerobic Respiration
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Anaerobic Respiration = Fermentation =
Glycolysis + Alcholic Fermentation or Lactic Acid Fermentation There are anaerobic bacteria (Clostridium botulinum) that release little energy from food. They exist with NO oxgyen present Alcohol fermentation = occurs in plant cells cells convert pyruviv acid or pyruvate from glycolysis into ethyl alcohol and carbon dioxide in the absence of oxygen bread baking.... beer production... Lactic Acid fermentation = occurs in animal cells during strenuous exercise when the body cannot keep up with the increased demand for oxygen by skeletal muscles pyruvic acid produced by glycolysis converts to lactic acid and builds muscle, causing fatigue and burn "no pain no gain" refers to pain caused by lactic acid build up in muscles when increase oxygen flow... restores oxygen levels, and the lactic acid is removed from the muscles. It is carried to the liver where is is converted back to pyruvic acid |
Aerobic Respiration
The Krebs Cycle aka The Citric Acid Cycle = first stage of aerobic respiration (WHEN Oxygen is present)
Pyruvic Acid (from glycolysis) combines with an enzyme which enters the Krebs cycle Occurs in the matrix of the mitochondria Each turn of the cycle makes 1 ATP and 1 FADH2 and 3 NADH CO2 is produced and exhaled NADH and FADH2
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Electron Transport Chain
ETC creates a gradient across the cristae membrane.
The gradient is used to produce ATP through chemiosmosis or oxidative phosphorylation. "All" ATP is produced during aerobic respiration is by chemiosmosis |
Part II: Chemiosmosis
Chemiosmosis uses stored energy in proton gradient to convert ADP to ATP. chemiosmosis = oxidative phosphorylation = mechanism that ATP is produced by means of the ATP Synthase enzyme in the cristae membrane Oxygen has a strong attraction for electrons and protons; it pulls electrons through the ETC; serves as final electron and proton receptor in the ETC. When oxygen combines with protons and electrons at the end of the ETC, water is formed as waste product (aka the water vapor we exhale) |
KEY IDEAS
- the ETC is a collection of carrier molecules (including cytochromes) embedded in the cristae membrane of the mitochondria
- every mitochondria has 1000's of ETCs
- the ETC carries electrons through a series of redox reactions (molecules bind to and let go of electrons)
- Reduction - electrons are gained; Oxidation - electrons are lost
- water is produced as a waste product (oxygen + protons and electrons that flow down the ETC)
- 1/2 O2 + H2 --> H2O
- protons cant's diffuse into cristae, they cross the ATP synthase channels
- each proton carried by NAD to the ETC produces 3ATPs; each proton carried by FAD produces 2 ATPs
Overview of Respiration:
Most energy flows....
glucose -> NAD and FAD -> Electron Transport Chain (chemiosmosis) -> ATP
glucose -> NAD and FAD -> Electron Transport Chain (chemiosmosis) -> ATP
Notes: (* Notes and Powerpoints adapted from Shannan Muskopf's fantastic teaching resource: Biology Corner.)
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