chapter 8 photosynthesis energy & life. ../videos/realplayer%20downloads/teachertube%20...
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Energy and Life Energy is the ability to do work Every activity depends on one kind of energy or another Chemical Solar ElectricalTRANSCRIPT
Chapter 8 Photosynth
esis Energy &
Life
../Videos/RealPlayer%20Downloads/TeacherTube%20Videos%20-%20Photosynthesis.wmv
Photosynthesis
Energy and Life Energy is the ability to do work
Every activity depends on one kind of energy or another
Chemical Solar Electrical
Chemical EnergyPotential Energy
Kinetic Energyof an Apple of an
Apple
Falling down
Solar Energy
Electrical Energy
Energy of Life Plants and some other types organisms are able to use light energy from the sun to produce food
Autotrophs Are organisms that produce their own food, and consequently, their own energy (Plants)
Heterotrophs
Are Organisms that have to obtain energy from food that they consume (Animals)
To Live, ALL Organisms must
release the energy in sugars and
other compounds
Chemical Energy and ATP
Energy can come in many formsLightHeat ElectricityChemical
Cellular activities are powered by chemical energy
◦Primarily ATP – Adenosine Triphosphate
▪Nitrogen –Containing Compound Adenine▪5 – Carbon Sugar Ribose▪3 – Phosphate Groups
Production of ATP
ADP (Adenosine Diphosphate) is the same as ATP except it has 1 less phosphate group
•Cell stores energy by attaching a phosphate group to ADP to form ATP
•Cell releases energy by detaching a phosphate group from ATP to form ADP
The characteristics of ATP make it an
exceptionally useful molecule that is
used by all types of cells as their basic
energy source
ATP powers the (Na+) \ (K+) pump in many membranes
◦Also powers movement of organelles within the cell
◦Moving along microtubles with motor proteins
◦Motor proteins use energy from ATP to move organelles
ATP and GlucoseMost cells have only enough ATP to last a
few seconds◦ATP not a good molecule to store large
amounts of energy▪A molecule of the sugar glucose stores
as much energy as 90 molecules of ATP ▪More efficient for cells to keep small
supply of ATP and ADP on hand… regenerate supply as needed from carbohydrates like glucose
Photosynthesis●When an organism uses light energy to convert water (H2O) and carbon dioxide (CO2) into oxygen (O2) and high-energy carbohydrates- sugars and starches
◦Plants then use the sugars to make complex carbohydrates
Photosynthesis Equation6 CO2 + 6 H2O → 6(CH2O) + 6 O2
Van Helmont’s Experiment ◦1600’s◦Did experiment to see if plants grew by
taking material from the soil▪He determined the mass of the dry soil
and small seedling▪Watered it regularly▪Grew for 5 years▪Determined the mass of the small tree
to be 75kg▪Mass of soil was unchanged
Van Helmont’s Experiment
▪Concluded that the water was the only contributing factor •“Hydrate” part of carbohydrate
▪Could not account for the addition of carbon•“Carbo” part of carbohydrate
▪He did not realize that the carbon was being extracted from the air around the plant in the form of CO2
Priestly’s Expeiment1700’s Took candle and lit it, placed it under a jar and observed that the flame went out after a while
Concluded that something in the air was present to keep the flame burning and when it was used up, the flame went out
That substance was Oxygen (O2)
Next, he placed a live sprig of mint under the jar for a few days
The candle would relight for a while
They produced O2Plants absorb CO2 and release O2
Later, Jan Ingenhousz that Priestly’s experiment only occur if the plant was exposed to sunlight
Showed that light is necessary for plants to produce O2
These Experiments, along with others, showed that in the presence of light, plants transform CO2 and H2O into carbohydrates and release O2
Light and Pigment Photosynthesis also requires Chlorophyll, a molecule in chloroplasts
Give them their green colorLight is actually made up of many
different wavelengthsDifferent colors in the visible and
invisible Spectrum Plants absorb sun’s energy with
molecules known as pigments
Principal pigment in plants is chlorophyll
2 Types: ◦Chlorophyll A◦ Chlorophyll B
Chlorophyll absorbs light well in the red and blue regions of the spectrum…not as well in the green part of the spectrum
This is why plants get their green color
When light is absorbed by the chlorophyll
Energy is transferred into electrons of chlorophyll molecule
Raises energy level of the electrons
These high energy electrons make photosynthesis work
The Reactions of Photosynthesis
Thylakoids are sac-like photosynthetic membranes found inside a chloroplast◦Arranged in stacks known as granaum
◦Contain clusters of Chlorophyll and Proteins known as Photosystems that are able to capture the energy from sunlight
◦Light dependant reactions
The Stroma is the area outside the Thylakoid
The Stroma is the area outside the Thylakoid◦Calvin Cycle◦Light independent reactions
NADPHA carrier molecule is a compound that accepts a pair of high energy electrons and transfer them along with their energy to another molecule ◊NADP+ is a carrier moleucle
◦◊Accepts a 2 e- and a H+
Converts it to NADPHThis is a way that some of the Suns energy can be captured in chemical form
NADPH then carries the high energy e-’s all over the cell to build a variety of molecules …Carbohydrates like glucose