Exam 10: Photosynthesis

Which of the following processes would be most directly affected if a thylakoid membrane is punctured so that the interior of the thylakoid is no longer separated from the stroma?

Students conducted an experiment to determine the effect of light intensity on the rate of photosynthesis. They punched 40 leaf disks from spinach leaves and used a syringe partially filled with water to pull the gases from the leaf disks so that all leaf disks sunk to the bottom of the syringe. Ten leaf disks from the syringe were placed in each of four cups and covered with 50 ml of the solutions as indicated below. All leaf disks were resting on the bottom of the cups when the experiment began. The volume of liquid in each cup and the temperature of the solutions were held constant. All cups were placed 0.5 metres from the designated light source. A large beaker of water was placed between the light and the cups to act as a heat sink to prevent a change in temperature. At the end of 10 minutes, the number of disks floating in each cup was recorded. Trial Grams of baking soda (CO2 source) Wattage of light bulb Disks floating at 10 minutes 1 0.5 25 3 2 0.5 50 5 3 0.5 75 9 4 0 75 0 Use your knowledge of the mechanism of photosynthesis and the data presented in the chart to determine which of the statements is a correct explanation for the students' data.

Which of the following statements summarises the metabolic results of photorespiration?

Carotenoids are often found in foods that are considered to have antioxidant properties in human nutrition. What related function do they have in plants?

Theodor W Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light. Which of the following statements describes a relationship that Engelmann's experiment helped to determine?

If photosynthesising green algae are provided with CO₂ containing heavy oxygen (18O), which of the following molecules produced by the algae (refer to the accompanying figure) will fail to contain 18O in later biochemical analyses?

- Which of the following statements is true concerning the accompanying figure?

In photosynthetic cells, synthesis of ATP by chemiosmosis occurs during ________.

Which of the following sequences correctly represents the flow of electrons during photosynthesis?

Why might the alternative pathways of photosynthesis using C4 or CAM systems be described as metabolic compromises?

In mechanism, photophosphorylation is most similar to

A spaceship is designed to support animal life for a multiyear voyage to the outer planets of the solar system. Plants will be grown to provide oxygen and to recycle carbon dioxide. Since the spaceship will be too far from the sun for photosynthesis, an artificial light source will be needed. Suppose a plant has a unique photosynthetic pigment and the leaves of this plant appear to be reddish-yellow. What wavelengths of visible light are absorbed by this pigment?

- Referring to the accompanying figure, where would elevated concentrations of oxygen inhibit carbon fixation reactions?

In the initial step in carbon fixation, a molecule of CO₂ is attached to RuBP to produce a six-carbon molecule, which is immediately split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to occur to complete the Calvin cycle?

A gardener is concerned that her greenhouse is getting too hot from too much light and seeks to shade her plants with coloured translucent plastic sheets, the colour of which allows passage of only that wavelength. What colour should she use to reduce overall light energy but still maximise plant growth?

Which of the following processes is most directly driven by light energy?

Which process is most directly driven by light energy?

What would be a likely consequence of a mutation in plants that results in a photorespiration deficiency?

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

Compared to C3 plants, C4 plants ________.