Unit 3b - AP classroom photosynthesis Practice Questions

The energy required to run the Calvin cycle reactions of photosynthesis comes from which two substances produced during the light-dependent reactions? A) ATP and NADPH B) ADP and PO4 C) H+ and PO2 D) O2 and CO2 E) H2O and CO2

A) ATP and NADPH

A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis. Which of the following observations provides the best evidence to support the claim? A) Elysia chlorotica will die if not exposed to light. B) Elysia chlorotica grows when exposed to light in the absence of other food sources. C) Elysia chlorotica grows faster when exposed to light than when placed in the dark. D) Elysia chlorotica grows in the dark when food sources are available.

B) Elysia chlorotica grows when exposed to light in the absence of other food sources.

Chlorophyll a: green phycocyanin: blue allophycocyanin: blue phycoerythrin: red Cyanobacteria contain a variety of pigment molecules, as shown in Table 1. As a result, the color of cyanobacteria cultures can vary significantly based on the relative amount of each pigment produced. A researcher placed a culture of cyanobacteria under green lights. Within a few weeks, the appearance of the cyanobacteria changed from green to red. The researcher claimed the color change in the culture was the result of an adaptation allowing greater photosynthesis. Which of the following provides the best reasoning to justify the researcher's claim? A) In green light, more chlorophyll a molecules are produced, reflecting more light to other cyanobacteria to be used for photosynthesis. B) In green light, more phycoerythrin molecules are produced, allowing more green light to be absorbed, thus increasing photosynthesis. C) In green light, cyanobacteria that have more phycocyanin molecules are less likely to survive and reproduce. D) In green light, cyanobacteria that have more allophycocyanin molecules are more likely to survive and reproduce.

B) In green light, more phycoerythrin molecules are produced, allowing more green light to be absorbed, thus increasing photosynthesis.

Process in which CO2, is released as a by-product of oxidation-reduction reactions A) Glycolysis B) Krebs cycle (citric acid cycle) C) Calvin cycle (light-independent reactions of photosynthesis) D) Light-dependent reactions of photosynthesis E) Chemiosmosis

B) Krebs cycle (citric acid cycle)

Process in which O2 is released as a by-product of oxidation-reduction reactions A) Glycolysis B) Krebs cycle (citric acid cycle) C) Calvin cycle (light-independent reactions of photosynthesis) D) Light-dependent reactions of photosynthesis E) Chemiosmosis

D) Light-dependent reactions of photosynthesis

A researcher claims that only a portion of the light energy captured by green plants is available for growth and repair. Which of the following observations best helps justify the researcher's claim? A)Light-capturing pigment molecules in green plants absorb red, blue, and violet light but reflect green light. B)The energy of a photon of light is proportional to its frequency and inversely proportional to its wavelength. C) As light energy is converted to chemical energy by metabolic processes, some of the energy is lost as heat. D) Captured energy is stored in the molecular bonds of organic molecules, including simple sugars and starch.

C) As light energy is converted to chemical energy by metabolic processes, some of the energy is lost as heat.

Process in which carbon from CO2 is incorporated into organic molecules A) Glycolysis B) Krebs cycle (citric acid cycle) C) Calvin cycle (light-independent reactions of photosynthesis) D) Light-dependent reactions of photosynthesis E) Chemiosmosis

C) Calvin cycle (light-independent reactions of photosynthesis)

In chloroplasts, ATP is synthesized from ADP plus inorganic phosphate (Pi) in a reaction catalyzed by ATP synthase molecules that are embedded in the thylakoid membrane. Which of the following statements provides evidence to support the claim that no ATP will be synthesized in the absence of a proton gradient? A) Blocking electron flow from one carrier to the next in the electron transport chains blocks formation of a proton gradient in the thylakoid. B) Increasing the proton concentration difference across the thylakoid membrane is not associated with a parallel increase in the rate of ATPATP synthesis. C)No ATP is synthesized when channel proteins that allow the free passage of protons are inserted into the thylakoid membrane. D)No ATPATP is synthesized while the Calvin cycle is synthesizing carbohydrates and using ATPATP and NADPHNADPH at a high rate.

C)No ATP is synthesized when channel proteins that allow the free passage of protons are inserted into the thylakoid membrane

In addition to the pigments commonly associated with photosynthesis, a certain photosynthetic species contains two additional pigment types. Which of the following best supports the claim that this species is better adapted to environmental changes than other photosynthetic species are? A) The increased pigment concentration better facilitates energy production within the cells of the species. B) The pigment combination allows the organism to absorb heat as well as light, making better use of available energy. C) The additional pigments allow the species to outcompete other species for the wavelengths of light commonly used in photosynthesis. D) The additional pigments allow the species containing them to harvest energy from wavelengths of light that the other photosynthetic species cannot use.

D) The additional pigments allow the species containing them to harvest energy from wavelengths of light that the other photosynthetic species cannot use.

Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis? A) The light-dependent reactions occur only during the day; the light-independent reactions occur only during the night. B) The light-dependent reactions occur in the cytoplasm; the light-independent reactions occur in chloroplasts. C) The light-dependent reactions utilize CO2 and H2O; the light-independent reactions produce CO2 and H2O. D) The light-dependent reactions depend on the presence of both photosystems I and II; the light-independent reactions require only photosystem I. E) The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH.

E) The light-dependent reactions produce ATP and NADPH; the light-independent reactions use energy stored in ATP and NADPH.