🧬 Biology · Energy
Photosynthesis flashcards
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All 17 flashcards at a glance
Card 1
What is photosynthesis?
The process in which living things use light energy to build sugar from carbon dioxide. Plants, algae and cyanobacteria also use water and release oxygen, and that is the kind this lesson covers.
Card 2
Write the simplified equation for photosynthesis in symbols.
6CO2 + 6H2O + light energy → C6H12O6 + 6O2. It is the net result of many steps.
Card 3
In which organelle does photosynthesis take place?
The chloroplast, found in plant and algae cells.
Card 4
What are thylakoids?
Flattened, membrane-bound sacs inside a chloroplast, stacked into grana. Chlorophyll sits in their membranes, and stage 1 happens there.
Card 5
What is the stroma?
The thick fluid inside a chloroplast that surrounds the thylakoids. The Calvin cycle happens here.
Card 6
Which colors of light does chlorophyll absorb best, and which does it reflect more?
It absorbs red and blue light best. It reflects more of the green light, which is why leaves look green.
Card 7
Name the two stages of photosynthesis.
Stage 1: the light-dependent reactions (thylakoid membranes). Stage 2: the Calvin cycle (stroma).
Card 8
What goes into and comes out of the light-dependent reactions?
In: light energy and water (plus ADP and NADP+ to be recharged). Out: oxygen gas, ATP and NADPH.
Card 9
What goes into and comes out of the Calvin cycle?
In: carbon dioxide, ATP and NADPH. Out: sugar, plus ADP and NADP+, which return to stage 1.
Card 10
What do ATP and NADPH do in photosynthesis?
They carry the energy captured in stage 1 over to the Calvin cycle in stage 2. NADPH also carries high-energy electrons.
Card 11
What is a limiting factor?
The factor in shortest supply, which sets the rate. Adding more of a different factor will not speed things up until the shortage is fixed.
Card 12
Name three factors that affect the rate of photosynthesis.
Light intensity, carbon dioxide concentration and temperature. (Water supply matters too, because a plant short of water closes its stomata.)
Card 13
What are stomata, and what do they do for photosynthesis?
Tiny pores in a leaf’s surface. They let carbon dioxide in and let oxygen out.
Card 14
Name two kinds of living things besides plants that photosynthesize.
Algae (which have chloroplasts) and cyanobacteria (bacteria with no chloroplasts).
Card 15
What energy change happens in photosynthesis?
Light energy is transformed into chemical energy stored in the bonds of sugar.
Card 16
What is carbon fixation?
Attaching carbon from carbon dioxide to a molecule inside the cell. It happens at the start of the Calvin cycle in the stroma.
Card 17
What can a plant do with the sugar it makes?
Use it in cellular respiration to make ATP, store it as starch, or build cellulose for cell walls and other molecules.