Photosynthesis

Where do the electrons entering photosystem II come from?

• water

• light

• ATP

• Electron Transport Chain

• chlorophyll molecules in the antenna complex

During photosynthesis in chloroplasts, O2 is produced from __________ via a series of reactions associated with __________.

• H2O … photosystem II

• CO2 … the Calvin cycle

• H2O … photosystem I

• CO2… photosystem II

• CO2 … both photosystem I and the Calvin cycle

Both mitochondria and chloroplasts __________.

• reduce NAD+, forming NADP

• obtain electrons from water

• release oxygen as a by-product

• use chemiosmosis to produce ATP

• are surrounded by a single membrane

You want to observe the movement of molecules throughout

photosynthesis. If you provide a plant with radioactive carbon

dioxide at the start of the process, where would you expect to

see those radioactive carbon molecules at the end of the

process?

• 1. In the oxygen gas

• 1. In the water molecules

• 1. In the produced sugars

• 1. It wouldn’t move anywhere

Rubisco is __________.

• the enzyme in plants that first captures CO2 to begin the Calvin cycle and is the most abundant protein in chloroplasts

• the first stable intermediate in C4 photosynthesis

• the enzyme that forms a 4-carbon compound in CAM photosynthesis

• the enzyme responsible for splitting H2O to produce O2 in photosynthesis

• the 5-carbon sugar molecule that reacts with CO2 to begin the Calvin cycle

Glyceraldehyde-3-phosphate (G3P) is produced in the stroma of chloroplasts. Which statement most completely describes this compound?

• It is a 3-carbon sugar.

• It is produced from glucose during glycolysis.

• For every three molecules of CO2, six molecules of G3P are formed, but only one molecule exits the cycle to be used by the plant cell.

• For every three molecules of CO2, six molecules of G3P are formed, but five molecules must be recycled to regenerate three molecules of RuBP

• All of the choices are correct.

You have a large, healthy philodendron that you carelessly leave in total darkness while you are away on vacation. You are surprised to find that it is still alive when you return. What has the plant been using for an energy source while in the dark?

• Even though it can't carry out the light reactions, the plant can still produce sugars because the Calvin cycle doesn't require light.

• Even though the plant received no visible light, it was able to use the short-wave part of the electromagnetic spectrum (gamma rays and X-rays) to carry out photosynthesis.

• While it did have access to light, the plant stored energy in the form of sugars or starch, and it was able to derive energy from the stored molecules during your vacation.

• When light energy is not available, plants can derive energy from inorganic molecules.

• None of the choice is correct.