Chapter 8 pre/post quiz

P680+ is often considered the strongest biological oxidizing agent. Given its function, why is this necessary?

• it obtains electrons from the oxygen atom in a water molecule, so it must have a greater affinity for electrons than oxygen has.

• it transfers its electrons directly to NADP+ to produce NADPH

• it is the molecule that transfers electrons to the photosynthetic electron transport chain

• it has a positive charge

• it is the receptor for the most excited electrons in either photosystem

where does the Calvin cycle take place?

• outer membrane of the chloroplast

• interior of the thylakoid (thylakoid space)

• thylakoid membrane

• stroma of the chloroplast

which of the following molecules are products of the light reactions of photosynthesis that are utilized in the Calvin cycle

• ATP and NADPH

• electrons and H+

• H2O and O2

• CO2 and glucose

If plants are grown in the light with CO2 containing a radioactive isotope of oxygen (18O), subsequent analysis will show that 18O incorporated in organic molecules first appears in

• the stroma

• the thylakoid membranes

• the thylakoid space

• mitochondria

what is the primary function of cyclic electron flow

• to produce additional oxygen

• to produce additional ATP

• to produce additional carbon dioxide

Which of the following reactions produces the oxygen released by photosynthesis

• splitting of water molecules

• chemiosmosis

• electron transfer in photosystem I

• reduction of NADP+

what is the relationship between wavelength of light and the quantity of energy per photon?

• They have a direct, linear relationship

• They are logarithmically related

• They are only related in certain parts of the spectrum

• They are inversely related

CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they

• fix CO2 into organic acids during the night when temperatures are cooler.

• fix CO2 into by combining it with RuBP in Calvin cycle.

• fix CO2 into organic acids in the bundle-sheath cells, which do not rely on stomata.

In mitochondria, the electron transport chain pumps proton from the matrix into the intermembrane space. In what direction are protons pumped by the electron transport chain in chloroplasts?

• from the stoma to the cytosol

• from the thylakoid space to the stroma

• from the stroma to the thylakoid space

• from the matrix to the stroma

• fro, the intermembrane space to the stroma

Why does photorespiration decrease the efficiency of photosynthesis?

• it reduces the amount of water consumed

• It produces excess NADPH but less ATP

• it reduces the amount of sugar produced

• it inhibits electron transfers from photosystem II

• It increases the amount of carbon dioxide consumed