Biology of Alleles Gene Expression 2 Questions (10/9)

What is the difference between light-dependent and independent reactions? Do they have other
names?

Light dependent/light reactions: require light to occur and produce ATP, NADPH, and O₂

Light independent reactions/Calvin cycle: reduces CO2 to carbohydrates, does not require light

What is the structure of a cell, and of a chloroplast? Can you tell how many membranes separate each compartment? How many membranes are between the lumen and the leaf airspace?

Cells have cell walls and a plasma membrane

Chloroplasts have double membranes. Inside is the stroma, which houses the thylakoids, and inside the thylakoids is the lumen

4 membranes: cell plasma membrane, double chloroplast membrane, and thylakoid membrane

What is transferred between chlorophylls? And what is transferred between PS’s? Energy, photons, electrons?

Energy is transferred between chlorophylls, and electrons are transferred between photosystems.

What colors of light are reflected and which are absorbed by plants? Do PSI and PSII absorb different spectra? Quantitatively how much green is reflected by leaves versus how much is absorbed?

Mostly green light is reflected, but all colors are absorbed and used by plants. PSII absorbs 680 nm, while PSI absorbs 700 nm. More green is reflected by leaves than absorbed

What is a key difference between anoxygenic and oxygenic photosynthesis? (other than the
involvement of O 2 )

Oxygenic uses water as an e^- donor

Anoxygenic uses other molecules, such as H₂S, as e^- donors

What purpose does cyclic electron transport have versus typical non-cyclic?

Non-cyclic produces NADPH, ATP, and O2

Cyclic produces ATP only

If the cell has too much NADPH, it’ll do more of cyclic