Chapter 10 Flashcards
(15 cards)
Photosynthesis - What is it and Players
Biochemical process for building carbohydrates using energy from sunlight and Carbon DIoxide CO₂
6CO₂+H₂O —>C₆H₁₂O₆+6O₂
Importance of Carbohydrates
Used to store energy in chemical bonds for later use
Carbs can be used a starting point for synthesis of other molecules (metabolic pathway)
Benefits of photosynthesis
Plants and other primary producers form the basis of all ecosystems
Fossil fuels(coal and oil) have their origin in photosynthetic organisms
Oxygen is produced as a byproduct
Photosynthetic organisms
First organisms thought to perform photosynthesis and cyanobacteria
Land plants (grasses, shrubs, and trees) are known for photosynthesis
Photosynthesis can take place in marine environments (phytoplankton, algae, even bacteria)
Anywhere sunlight is available in photosynthesis can take place
Photosynthesis: The chemical reaction
Process involves two types of reactions
Reduction - reaction where a molecule gains electrons and energy
Oxidation- reaction where a molecule loses electrons and loses energy
Molecule that gains electrons ( gains energy) is reduced
Molecule that loses electrons is oxidized
Reaction takes place together, known as redox reaction
Photosynthesis as a redox reaction
Glucose is reduced
Oxygen is oxidized
6CO₂+6H₂O—>C₆H₁₂O₆+6O₂
Photosynthesis has 2 parts
Light reactions (1st stage)
Calvin cycle (2nd stage)
Light reactions (1st stage)
* Energy from sunlight converted into chemical energy
* Energy held in bonds of ATP+NADPH
* This energy is carried over to 2nd stage
* Light-dependent
Calvin cycle (2nd stage)
* Conversion of CO₂—>Carbohydrate
* This uses the stored energy from light reactions
* Light independent
Location! Location! Location!
Both reactions take place in the chloroplasts(Eukaryotes)
Thylakoids, build to attract and grab as much sunlight as possible
Space surrounding the thylakoid is the stroma, where the Calvin cycle takes place
Electromagnetic Spectrum
Visible light - the portion of the spectrum our eyes can see
Wavelength of visible light is 400-700 nm
Visible light is used for photosynthesis
Pigments - molecules that absorb visible light
Leaves are full of chloroplast (organelle) which contain the pigment chlorophyll which does not absorb green light well
The color we see on healthy leaves is reflected green light
Light reaction - ATP synthesis
H+ (ion) build up after the loss of e- in the thylakoid
H+ from the stroma crosses over, resulting in a difference in concentration
Thylakoid membrane blocks diffusion of H+ resulting in buildup of PE.
ATP Synthase provides a channel, harnesses the KE of proton movement across
With the KE it synthesizes ATP from ADP-P
ADP+P_i=ATP
Calvin Cycle 3 Steps
Fixation
Reduction
Regeneration
Calvin Cycle
Fixation
CO₂ (inorganic carbon) is converted into an organic carbon
Organic carbon can be used throughout the body (usually in macromolecule building)
Rubisco (RuBP) catalyzes the process
Calvin Cycle
reduction
Energy from ATP and NADPH is used to synthesize triose phosphate
Triose phosphate is later converted into glucose
Calvin Cycle
Regeneration
RuBP is regenerated
Storage of carbohydrates
Excess carbohydrates created by the Calvin cycle are converted to starch for storage
This reaction dehydrates carbohydrates for future use, and prevents the actions of osmosis
These can be used during the night when photosynthesis is inefficient
