Photosynthesis Flashcards
where does photosynthesis occcur?
tylakoid
What is the stroma?
fluid around the thylakoid – contains the pigment chlorophyll
_____________resides in the thylakoid membrane?
chlorophyll
Photosynthesis is a ________reaction?
redox
in photosynthesis______is split and the electrons and H+ are transferred to CO2 reducing it to sugar electrons increase in potential energy. the reaction is______________
water
endergonic
In photosynthesis: plants convert radiant energy from the sun into chemical energy in the form of glucose and sugar. what is the formula?
water + CO2 + Sunlight ——> glucose + oxygen 6H2O+ 6CO2 + radiant energy —> c6h12o6 + 6o2 reverse of cellular respiration-biochem pathways aren’t the same-separate pathways
- Light is a form of energy = electromagnetic radiation • The entire range of radiation is the electromagnetic spectrum – What we can detect as various colors = visible light (380‐750nm)
- _______ = discrete particles with a fixed amount of energy (no mass!) Why is the sky blue? Why does something appear white? Black?
Photons
why is the sky blue? wavelengths in blue area of spectrum reflected by particles in the air and make its way to the eye. red shirt, red reflected.
appear white-reflects everything
appear black-reflects nothing
• ________ = substance that absorbs visible light – Different pigments absorb different wavelengths of light – Chlorophyll a & b appear green because they do not absorb wavelengths in that part of the spectrum – Why do leaves change colors?
pigments
Leaves are colored by molecules called pigments. The pigment that causes leaves to be green is chlorophyll. Chlorophyll is important for plants to make food using sunlight. During spring and summer when there is plenty of sunlight, plants make a lot of chlorophyll.
In autumn when it starts to get cold, some plants stop making chlorophyll. Instead, those plants break down chlorophyll into smaller molecules. As chlorophyll goes away, other pigments start to show their colors. This is why leaves turn yellow or red in fall.
The color change usually happens before the leaves fall off of the tree. Why might that be? It takes a lot of energy to make chlorophyll. If the plants break down the chlorophyll and move it out of their leaves before the leaves fall, plants save energy. The plants can reabsorb the molecules that make up chlorophyll. Then, when it’s warm and sunny enough to grow again, the plants can use those molecules to remake the chlorophyll. That way the plants don’t have to make chlorophyll from scratch.
Light Reactions –
Convert _____ energy into _________ energy
- H2O is split to provide e‐ and H+
- NADP+ reduced to NADPH
- ATP is produced
- O2 is given off
light energy to chemical energy
• Calvin Cycle (Light Independent/Dark Reactions)
– Fixes ______ from CO2 into organic molecules
– Reduces fixed carbon into sugar using the _____ and ___ from light reactions
Carbon
NADPH and ATP
– ___________________: contain pigment molecules which absorb light and transfer the energy to reaction‐center complex (i.e. antenna) –
light harvesting complexes
what is the equation for light reactions?
Light + H2O ———–> NADPH + ATP + O2
___________________: contains a special pair of chlorophyll a molecules which can reduce the primary electron acceptor
reaction-center complex
• Photosystems which capture light are located in the__________ membrane
thylakoid
T/F Photosystem 2 is before photosystem 1
True
Calvin Cycle • Broken down into 3 phases: – ___________ • Rubisco (RuBP carboxylase) attaches CO2molecule to ribulose bisphosphate (RuBP) – ___________ • Carbon intermediate received phosphate group from ATP • Reduced by NADPH and loses the phosphate = G3P – __________________ • Series of steps which utilize ATP to rearrange 5 molecules of G3P to regenerate 3 molecules of RuBP
• Uses the chemical energy stored in ATP and NADPH to reduce CO2 to sugar (G3P)
1st phase of the carbon cycle?
carbon fixation Rubisco (RuBP carboxylase) attaches CO2molecule to ribulose bisphosphate (RuBP)
2nd phase of carbon cycle?
Reduction
- Carbon intermediate received phosphate group from ATP
- Reduced by NADPH and loses the phosphate = G3P
3rd phase of the calvin cycle?
Regeneration of Co2 acceptor
• Series of steps which utilize ATP to rearrange 5 molecules of G3P to regenerate 3 molecules of RuBP
Cycle must occur ___ to produce 1 net G3P (Fixing 3 CO2) – Technically produces 6 G3P molecules but 5 must be used to regenerate RuBP • For 1 G3P, cycle uses 9 ATP and 6 NADPH
3X
The series of reactions in the calvin cycle have to regenerate____________?
co2 acceptor
What Happens to the Sugar Produced? •
~50% is used as fuel for cellular respiration
– Transported throughout the plant (only green parts of photosynthetic)
• Linked together to form _______ • Excess stored as ______ • Makes ~160 BILLION metric tons of carbohydrate per year – Equal to about 60 trillion copies of your textbook • 17 stacks from here to the sun
cellulose, starch
