Chapter 10 (Photosynthesis) Flashcards
Is photosynthesis exergonic or endergonic?
endergonic because it is absorbing energy
In photosynthesis, what does light energy turn into?
chemical energy
Why does photosynthesis break down water?
to grab electrons to put them back into organic molecules and have oxygen as a waste product
Where does photosynthesis take place?
chlorophyll
Where is the granum located?
inside the chloroplast (oval shapes stacked on top of one another)
What is a granum?
a stack of thylakoids (those oval shapes)
What is a chlorophyll?
a photoreceptor that captures light energy
Where is the chlorophyll located?
dots located on thylakoid membrane (anchored in)
What is the thylakoid membrane?
the membrane around the thylakoid
What type of ring does chlorophyll have?
porphyrin ring (Mg in the middle)
Where does the reaction happen in chlorophyll on the porphyrin ring?
at the R group, also has a hydrocarbon tail to anchor
How do the electrons get energized in photosynthesis as the chlorophyll ring gets to a higher energy structure?
by light energy
What is the energy transfer in chlorophylls called?
resonance energy transfer
What forms does chlorophyll come in?
chlorophyll a and chlorophyll b
What is the differences between chlorophyll a and chlorophyll b?
chlorophyll a R group is CH3
chlorophyll b R group is CHO
What color is chlorophyll good at absorbing?
violet to blue and yellow to red, NOT GREEN
What are accessory pigments?
helping chlorophyll absorbing light, recognized by colors
Where are accessory pigments located?
on the thylakoid membranes
What are carotenoids?
accessory pigments (beta carotene), orange color
What are another type of catenoid?
accessory pigments, xanthophyll, comes as lutein and expressed as yellow
What vitamin do we get beta-carotenes from?
vitamin A
Why is vitamin A so important for humans?
beta carotenes help with bringing retinoic acid to the retina so that the retina can capture the light energy with photoreceptors on the membrane and generate membrane potential for a neuron signal
What energy do we see as the accessory pigments absorb light energy?
You see the energy it does NOT absorb
What are anthocyanins?
accessory pigments manufactured from sugar rings sometimes, expressed as purple/red
When the leaf starts dying and the chlorophyll starts dying rapidly, what happens?
the leftover is the changing of colors since the accessory pigments take longer to degrade
What are tannins?
leave the brown color after the rest of the pigments die
What is carbon fixation?
taking carbon in the gaseous form fixing it into G3P phosphate
What are the stages of photosynthesis?
light-dependent reactions aka photophosphorylation
Calvin cycle
What is the stroma?
fluid inside the chloroplast (where Calvin cycle takes place)
What does the thylakoid membrane act like in regards to cellular respiration?
the electron transport chain
In the thylakoid membrane, what is the first photosystem?
photosystem II w/ p680
In the thylakoid membrane, what is the second photosystem?
photosystem I w/ p700
What is in between photosystem II and I?
complex (etc)
What happens during the light dependent reaction?
photons electrons excite chlorophyll molecules to get into a high energy stage, as the energy stage lowers the H+ get pumped into the thylakoid space to create a gradient for ATP synthase to generate ATP
What is located after photosystem I?
ATP synthase
What are the light dependent reactions called?
photophosphorylation
What is the final electron accepter for photophosphorylation?
NADP+
Where does H2O split and become O2?
near photosystem II, called oxygen-evolving complex
Why does H2O get split?
donate electrons and hydrogens to replace the ones that got excited and left from photosystem II
What does photophosphorylation produce?
ATP and NADPH
What are reaction centers?
the chlorophyll molecules at the “center” that get excited after electrons keep hitting it and after absorbing light
What part of photophosphorylation is noncyclic?
photosystem II, ETC
What part of the photophosphorylation is cyclic?
photosystem I
What is the first step in photophosphorylation?
photons absorbed in photosystem II, energy excites electrons and gets to the reaction enter P680 to boost electrons to highest level
What is the second step in photophosphorylation?
excited electrons passed to electron acceptor (PQ) and waters gets split to H and O2 to replaces the lost electron in photosystem II
What is the third step in photophosphorylation?
electron acceptor brings excited electron to etc, etc denergizes the molecules and pump out 4 H+
What is the fourth step in photophosphorylation?
PC (electron acceptor) brings de-eergized electron to photosystem I, photons hit photosystem I and energizes electron to get to P700
What is the fifth step in photophosphorylation?
electrons travels down another short etc via PC and NADP+ goes to NADPH and the protons go through ATP synthase to make ATP
Where does the Calvin Cycle take place?
the stroma
What is the purpose of the Calvin cycle?
to fix carbon and make 3-carbon sugars
What fuels the Calvin Cycle?
NADPH and ATP
What is the first step in the Calvin Cycle?
CO2 + ribulose 1, 5 bisphosphate (RuBP, 5 carbon sugar ring) to make 2 molecules of 3-phosphoglycerate
What is the second step in the Calvin Cycle?
phosphoglycerate kinase breaks ATP to ADP + P —–> 1,3 diphosphoglycerate
What is the third step in the Calvin Cycle?
G3P dehydrogenase breaks NADPH to NADP+ —–> G3P (3, carbon sugar)
What is the fourth step in the Calvin Cycle?
1 G3P go to glucose and 5 G3P get converted into ribulose 1,5 bisphosphate via kinase (ATP to ADP +P)
How many CO2 need to go through the calvin cycle for one G3P to get out?
3 CO2
When three CO2 molecules enter, how many G3P molecules made?
6 G3P (1 goes to glucose, 5 get converted to 1,5 ribulose bisphosphate)
mnemonic for Calvin cycle
rick (rubisco) please (3 - phosphate) bake (1,3 bisphosphate) good (G3P) raisins (ribulose 1,5 bisphosphate)
What does the Calvin Cycle produce?
sugar from CO2, using ATP and NADPH
What does the Calvin cycle begin with?
carbon fixation, incorporating CO2 into organic molecules
Does the Calvin cycle depend on the light directly?
no they are considered light-independent because they indirectly use light
