photosynthesis or “how plants eat sunshine”. plants don’t eat cheeseburgers. where do plants...
TRANSCRIPT
Photosynthesisor
“How Plants Eat Sunshine”
Plants don’t eat cheeseburgers.
• Where do plants get the food to create the energy they need to grow and reproduce?
PHOTOSYNTHESIS!
What do you already know about Photosynthesis?
• It produces Oxygen.
• It uses CO2.
• It happens in plants.• Uses light.
• Chloroplasts.• Chlorophyll• Starch is produced.
What have we learned in lab?
• Photosynthesis takes place where chlorophyll is present - the green parts
• Photosynthesis produces starch
• Photosynthesis (O2 production) occurs in the light.
How does Photosynthesis work?
• Photosynthesis is the process of TRANSFORMING LIGHT ENERGY into CHEMICAL ENERGY (food, or GLUCOSE).
Light Glucose
BUT HOW??
Let’s look at a plant cell.
Here’s the chloroplast.
Chloroplasts…• Have stacks of thylakoids –a stack of
thylakoids is called grana.
• Have a stroma-
Space
surrounding the
thylakoids
Chloroplasts are GREEN so…
• Sunlight is part of the VISIBLE spectrum
• White light can be separated by wavelengths.
• Wavelengths correspond to different colors.
• The colors you see are being RFLECTED.
• CHLOROPHYLL is the pigment molecule that makes plants green and is responsible for photosynthesis.
• GREEN IS BEING REFLECTED.
• Light that is ABSORBED is used during photosynthesis.
• ALL OTHER LIGHT IS USED FOR PHOTOSYNTHESIS.
Chloroplasts are GREEN so…
The Light Dependent Reaction:uses water and produces O2
Step 1: the ETC (light DEPENDENT reactions)
• An electron Transport Chain (ETC) is an electron conveyer belt.
• Electrons (e-) move down the chain and are picked up and make new molecules.
• The ETC is located in the THYLAKOID MEMBRANE.
Step 1: the ETC(light DEPENDENT reactions)
• Light hits chlorophyll and excites an e-. The e- starts moving down the chain. This leaves an empty space.
Chlorophyll
ETC
e-
• H2O is split. O2 donates an electron to fill the empty space in the chain and diffuses out. H+ stays in the thylakoid,making an H+
gradient.• The OXYGEN
is released!
O- + H+ H+
e-
Step 1: the ETC(light DEPENDENT reactions)
• H+ diffuses out through ATP synthase, to make ATP. http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter10/
animations.html
H+ H+ H+ H+ H+ H+ H+ H+ H+
ATP!!
ATP Synthase
e-
H+
Step 1: the ETC(light DEPENDENT reactions)
• Electrons are picked up from the ETC and used to take H+ to the CALVIN CYCLE.
Step 1: the ETC(light DEPENDENT reactions)
e-
NADP+e-+H+NADPH
H+ H+ H+ H+ H+ H+ H+ H+ H+
H+ ATP!!
http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter10/animations.html#
The CALVIN CYCLE aka
THE DARK REACTIONS:Consume CO2 and produce Glucose
(C6H12O6)
Step 2: The Calvin Cycle(Light INdependent reactions)
• H+ is transferred to the CALVIN CYCLE in the stroma.
Stroma: the dark middle part of the thylakoid.
Step 2: the Calvin Cycle(the DARK reactions)
CO2 diffuses into the chloroplast
And enters the
Calvin Cycle. CALVIN CYCLE
CO2
• H+ enters the Calvin Cycle.• Energy from ATP created during the Light
Dependent Reactions is used to ...
Step 2: the Calvin Cycle(the DARK reactions)
combine 6 molecules of CO2 and 12 H+ to make …
GLUCOSE (C6H12O6)!http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter10/animations.html
Step 2: the Calvin Cycle(the DARK reactions)
CO2
H+
C6H12O6
Step 1 and Step 2:
• http://www.tracy.k12.ca.us/thsadvbio/animations/Photosynthesis.swf
The Bottom Line...
• Photosynthesis occurs in plants.• Photosynthesis uses sunlight to make starch.• Photosynthesis takes place in the chloroplast
using chlorophyll.• Oxygen released from plants comes from
WATER – NOT CO2
• CO2 and H+ (also from water) are used to make C6H12O6.
• Photosynthesis has 2 reactions:
LIGHT DEPENDENT and LIGHT INDEPENDENT.
• Light Dependent Reactions = Thylakoid
• Light INdependent Reactions = Stroma
• CO2 + H2O + ATP SUNLIGHT C6H12O6 + O2
The Bottom Line...
So… why should we save the rainforest?
We need the Oxygen to make our own energy – ATP – during
cellular respiration!
Coming up next in Biology...
How do our cells use Oxygen from plants to make ATP??