Chapter 10: Photosynthesis Flashcards
This deck will aid you in understanding photosynthesis and the processes that are needed to complete it. (28 cards)
What is photosynthesis?
The process by which green plants and some other organisms use sunlight to synthesize foods with carbon dioxide and water
What is the chemical formula for photosynthesis?
6CO2 + 6H2O + (light) —} C6H12O6 + 6O2
What is the chemical formula for glucose, specifically?
C6H12O6
Again, specifically for glucose
What are the stages of photosynthesis?
Stage One: Light-dependent reactions
Stage Two: Calvin Cycle/dark reactions/light-independent reactions
What is the byproduct of photosynthesis?
Oxygen
What is the byproduct/s of cellular respiration?
Carbon dioxide (and water)
How are photosynthesis and cellular respiration the opposite of one another?
Photosynthesis and cellular respiration use the opposite reactants and yield opposite products
Describe the structure of the chloroplast.
Refer to worksheet.
What are the light-dependent reactions?
Uses light energy to make two molecules needed for the next stage of photosynthesis: ATP and NADPH; in plants, the light reactions take place in the chloroplasts, specifically in the thylakoid membranes
What are photosystems?
Light-absorbing molecules that are optimized to harvest light; there are two types of photosystems: photosystem 1 (PSI) and photosystem 2 (PSII)
Summarize what occurs in the light-dependent reactions.
Electrons are removed from water (H2O) and passed through PSII and PSI respectively before ending up in NADPH; this process requires light to be absorbed twice, once in each photosystem, and it makes ATP
What happens in the light-absorption in PSII?
When light is absorbed in photosystem 2, energy is passed inward until it reaches the reaction center; there, energy is transferred to an electron; the high-energy electron is passed to an acceptor molecule and replaced with an electron from water; the splitting of water two times releases the O2 we breathe
Can oxygen stand on its own?
No.
What happens in ATP synthesis in the light-dependent reactions?
The high-energy electron travels down an electron transport chain; some of the released energy drives the pumping of H+ ions from the stroma into the thylakoid interior (lumen; active transport), thereby building a higher concentration of ions inside the thylakoid; as H+ ions flow down their gradient and into the stroma, they pass through ATP synthase, driving ATP production in a process known as chemiosmosis
Where do the light-dependent reactions occur?
In the thylakoid
Where do the light-independent reactions occur?
In the stroma
What are the products of the light-dependent reactions?
ATP
NADPH
O2 (oxygen gas)
What are the products of the Calvin cycle?
Sugar (glucose)
ADP + P
NADP+
How many protons are pumped from an electron going from PSII to PSI?
Three protons
What happens in light absorption in PSI in the light-dependent reactions?
The electron arrives at photosystem 1; when light energy is absorbed and passed inward to the reaction center, the electron is boosted to a very high energy level and transferred to an acceptor molecule; the special pair’s missing electron is replaced by a new elevtron from PSII (arriving via the electron try chain)
What happens in NADPH formation in the light-dependent reactions?
The high-energy electron travels down the electron transport chain; at the end of the chain, the electron is passed to NADP+ to make NADPH
Is it important to remember that an electron resides in each photosystems at one time?
More or less, yes.
But, do note that the splitting of water seems to only fuel the process and does not occur with PSI.
What is the net effect of the light-dependent reactions?
To convert light energy into chemical energy in the form of ATP and NADPH
What happens in the Calvin cycle/light-independent reactions?
In plants, CO2 enters the interior of a leaf via pores called stomata and diffuses into the stroma of the chloroplast. In the Calvin cycle, sugars are synthesized. Carbon atoms from CO2 are incorporated into larger molecules and used to build three-carbon sugars
