Photosynthesis I: Harnessing the Energy of the Sun

The products of photosynthesis are

• a.water and carbon dioxide.
• b.sugar and water.
• c.sugar and oxygen.
• d.oxygen and water.

In Priestley’s experiments, what was released by the mint sprig and allowed the candle to burn again?

• a.oxygen
• b.water vapor
• c.carbon dioxide
• d.nitrogen

When a photon of light energy reaches a reaction center chlorophyll molecule, what becomes excited?

• a.a molecule of water vapor
• b.an electron
• c.a carbon dioxide molecule
• d.an atom of oxygen

The difference between P700 and P680 is that

• a.the concentration of chlorophyll molecules is greater in P700.
• b.P680 is only used in the cyclic electron flow.
• c.P680 is found in algae while P700 is found in land plants.
• d.P700 absorbs light with a wavelength of 700 nm.

The products of the light-dependent reactions of photosynthesis are

• a.sugar and water.
• b.sugar and oxygen.
• c.ATP, NADPH, and oxygen.
• d.ATP and sugar.

__________ is the final electron acceptor in photosystem I.

• a.Water
• b.Chlorophyll
• c.NADP+
• d.Oxygen

What is the purpose of cyclic electron flow?

• a.It creates water needed for cellular respiration.
• b.It creates only ATP, needed by the light-independent reactions.
• c.It supplies electrons for photosystem I.
• d.It cleaves water into oxygen and hydrogen ions.

Why do plants appear green?

• a.They absorb green light.
• b.They excite electrons which emit green light in the visible spectrum.
• c.They reflect green light.
• d.They absorb electrons by green pigments when exposed to sunlight.

Light-harvesting complexes, excited by photons of light, are made of

• a.proteins and sugars.
• b.proteins, cofactors, and pigment.
• c.pigment and sugars.
• d.proteins and water.

When electrons are passed through an electron transport chain, released energy

• a.is lost as heat.
• b.splits water into hydrogen and oxygen.
• c.fuses carbon dioxide molecules into a sugar.
• d.is transformed into a hydrogen ion gradient to drive ATP synthesis.