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VICBiologyQuick questions
Unit 3: How do cells maintain life?
Quick questions on Photosynthesis (light-dependent and Calvin cycle): VCE Biology Unit 3
15short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.
What is light-dependent stage (thylakoid membrane)?Show answer
Location. The thylakoid membranes and the lumen they enclose, inside the chloroplast.
What is light-independent stage (stroma, Calvin cycle)?Show answer
Location. The stroma of the chloroplast (the fluid surrounding the thylakoids).
What is factors affecting the rate of photosynthesis?Show answer
Light intensity. Rate rises with intensity until another factor becomes limiting. Very high intensity can damage chlorophyll (photoinhibition).
What is c3, C4 and CAM plants?Show answer
C3 plants (for example, wheat, rice, most temperate species). RuBisCO fixes CO2 directly in mesophyll cells, producing a 3-carbon intermediate (3-PGA). They photorespire when hot and dry.
What is location?Show answer
The thylakoid membranes and the lumen they enclose, inside the chloroplast.
What is inputs?Show answer
Light energy (absorbed by chlorophyll in photosystems II and I), water, ADP and inorganic phosphate (Pi), and NADP+.
What is outputs?Show answer
Oxygen, ATP and NADPH.
What is light intensity?Show answer
Rate rises with intensity until another factor becomes limiting. Very high intensity can damage chlorophyll (photoinhibition).
What is cO2 concentration?Show answer
Rate rises with CO2 up to a plateau. CO2 is typically the limiting factor at high light.
What is temperature?Show answer
Rate rises with temperature up to an optimum (around 25 to 35 degrees Celsius for most C3 plants), then falls as enzymes such as RuBisCO denature. At high temperatures RuBisCO also reacts with O2 (photorespiration), wasting fixed carbon.
What is water availability?Show answer
Low water closes stomata, reducing CO2 entry.
What is chlorophyll and wavelength?Show answer
Chlorophyll absorbs red and blue light strongly and reflects green; rate is highest under red and blue light.
What is saying photosynthesis happens "in the chloroplast" without specifying the substructure?Show answer
Light-dependent reactions occur on the thylakoid membrane; the Calvin cycle occurs in the stroma.
What is forgetting where O2 comes from?Show answer
Oxygen comes from the photolysis of water, not from CO2.
What is mixing up NADP+ and NAD+?Show answer
NADP+ is reduced to NADPH in photosynthesis. NAD+ is reduced to NADH in cellular respiration.