My AP Questions Unit 4

Carbohydrate-synthesizing reactions of photosynthesis directly require

products of the light reactions

What materials move into or out of a plant through the stomata? (Choose all that are correct)

water,carbon dioxide,oxygen

What materials move into a plant through the roots? (Choose all that are correct)

water,nitrogen,minerals

Through what vessel does water move throughout the plant?

xylem

he energy required to run the Calvin cycle reactions of photosynthesis comes from which two substances produced during the light-dependent reactions?

ATP abd NADPH

A researcher claims that increased atmospheric carbon dioxide levels cause increased growth rates in plants. Which of the following statements best supports the researcher's claim?

Atmospheric carbon dioxide is the raw material for photosynthesis, which plants rely on for producing sugars and other organic compounds.

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. Process in which carbon from CO2 is incorporated into organic molecules (A) Glysolysis (B) Krebs cycle (citric acid cycle)(C) Calvin cycle (light-independent reactions of photosynthesis) (D) Light-dependent reactions of photosynthesis (E) Chemiosmosis

C(Calivin Cycle)

Directions: This group of questions consists of five lettered headings followed by a list of phrases or sentences. For each phrase or sentence, select the one heading to which it is most closely related. Each heading may be used once, more than once, or not at all. Process in which O2 is released as a by-product of oxidation-reduction reactions (A) Glysolysis (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)

What most likely causes the trends in oxygen concentration shown in the graph above?

Photosynthesis produces more oxygen than is consumed by respiration during the day

chem equation for photosynthesis If the input water is labeled with a radioactive isotope of oxygen, 18O, then the oxygen gas released as the reaction proceeds is also labeled with 18O. Which of the following is the most likely explanation?

During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.

What is the main force that moves water through the plant?

Evaporation causing transpiration

The O2 released during photosynthesis comes from

H2O

How does sugar move through a plant?

Sugars move from the "source" to the "sink"

What causes the stomata to open?

K+ ions move into the guard cells and water follows passively making the guard cells turgid

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 across the thylakoid membrane?

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

Which of the following is an important difference between light-dependent and light-independent reactions of photosynthesis?

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

Which structure ensures that everything entering the plant through the roots must be selected for by crossing a membrane before entering the xylem?

casparian strip

Under which conditions would transpiration occur most slowly?

cool, humid weather

A student placed 20 tobacco seeds of the same species on moist paper towels in each of two petri dishes. Dish A was wrapped completely in an opaque cover to exclude all light. Dish B was not wrapped. The dishes were placed equidistant from a light source set to a cycle of 14 hours of light and 10 hours of dark. All other conditions were the same for both dishes. The dishes were examined after 7 days, and the opaque cover was permanently removed from dish A. Both dishes were returned to the light and examined again at 14 days. The following data were obtained. According to the results of this experiment, germination of tobacco seeds during the first week is

increased by exposure to light