Exam 8: Photosynthesis: Using Sunlight to Build Carbohydrates

Which of the following BEST describes the benefit to early photosynthetic organisms gained by having two different photosystems in one cell?

In a thylakoid membrane, absorbed light energy is passed from one chlorophyll molecule to another until it is:

Which of the following CORRECTLY lists the path taken by electrons through the light dependent reactions of photosynthesis?

The first photosynthetic organisms probably used chlorophyll as the primary light-absorbing pigment.

Which of the following outcomes would you expect if the pH of the thylakoid lumen increases from 4 to 6?

Beginning with the step catalyzed by rubisco, arrange the steps in the Calvin cycle in the proper sequence in which they occur.

In the evolution of photosynthesis, which process happened FIRST?

Which of the following is needed directly to produce both triose phosphates and RuBP?

Two petri dishes of radish seeds are prepared as follows: a disk of absorbent, but otherwise inert, filter paper is placed in the bottom of each dish and 5 mL of distilled water are added to each disk, then 2 grams of dry radish seeds are spread over each moist disk. One dish is put in a dark cupboard and the other is put on a sunny windowsill. The investigator checks the dishes daily and adds water equally as needed. Seeds in both treatments germinate within 2 days. At the end of 10 days, the plant material on each petri plate is dried and weighed. The results are: - - starting dry weight 2.00g - sunny windowsill 2.25g - dark cupboard 1.75g What is the MOST likely explanation for why the dark-grown seedlings lost biomass?

The ratio of ATP to NADPH used by the Calvin cycle is approximately 3:2 (3 molar ATP used for each 2 molar NADPH). What is the MINIMUM number of these molecules required to synthesize one mole of glucose?

A new experimental pesticide is being tested by a large agricultural chemical company. An unfortunate side effect in plants treated with this new product is a decrease in NADPH production in the chloroplasts. (Interestingly, reduction of NAD⁺ to NADH in the mitochondria is unaffected.) Given this observation, what specific change(s), if any, would you expect to observe in the intermediate compounds of photosynthesis in the chloroplasts of these plants?

Many photosynthetic prokaryotes are capable of cyclic electron transport only. It is likely that such organisms can _____ but not _____.

As electrons flow through the light-dependent reactions, they become associated with several molecules and molecular complexes. When do the electrons have the GREATEST amount of energy?

In photosynthesis, the reduction of 3-phosphoglycerate to form carbohydrate requires:

With the endosymbiotic hypothesis in mind, which of the following within modern-day chloroplasts is likely derived from the cytoplasm of ancestral cyanobacteria that took up residence within a eukaryotic cell?

The regeneration of RuBP typically limits the rate of photosynthesis under low light intensities. This is because:

Two petri dishes of radish seeds are prepared as follows: a disk of absorbent, but otherwise inert, filter paper is placed in the bottom of each dish and 5 mL of distilled water are added to each disk, then two grams of dry radish seeds are spread over each moist disk. One dish is put in a dark cupboard and the other is put on a sunny windowsill. The investigator checks the dishes daily and adds water equally as needed. Seeds in both treatments germinate within 2 days. At the end of 10 days, the plant material on each petri plate is dried and weighed. The results are: - - starting dry weight 2.00g - sunny windowsill 2.25g - dark cupboard 1.75g How did the increased biomass in the sunlit dish arise (i.e., where did the additional mass come from and by what process)?

Collectively, most photosynthesis carried out in the ocean is performed by single-celled organisms as opposed to large, multicellular marine plants.

A photosynthetic electron-transport chain captures in chemical form approximately what percentage of the sun's usable energy arriving at the surface of a leaf?

Photosynthesis is the pathway used to synthesize carbohydrates from: