Photosynthesis Test
The alternative pathways of photosynthesis using the C4 or CAM systems are said to be compromises. WHY?
Both minimize photorespiration but expend more ATP during carbon fixation.
Carbohydrate-synthesizing reactions of photosynthesis directly require
products of the light reactions
The energy required to run the Calvin cycle reactions of photosynthesis comes from which two substances produced during the light-dependent reactions?
ATP & NADPH
A researcher claims that increased atmospheric CO2 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
Process in which carbon from CO2 is incorporated into organic molecules
Calvin cycle (light independent reactions of photosynthesis)
What most likely causes the trends in oxygen concentration shown in the graph below?
Photosynthesis produces more oxygen than is consumed by respiration during the day.
A scientist claims that Elysia chlorotica, a species of sea slug, is capable of photosynthesis.Which of te following observations provides the best evidence to support the claim *
Elysia chlorotica grows when exposed to light in the absence of other food sources.
The O2 released during photosynthesis comes from
H2O
The chemiosmotic hypothesis is an important concept in our understanding of cellular metabolism in general because it explains _____.
How ATP is synthesized by a proton motive force
Which of the following questions is most relevant to understanding the Calvin cycle?
How is ATP used in the formation of 3-carbon carbohydrates?
Process in which O2 is released as a by-product of oxidation-reduction reactions
Light-dependent reactions of photosynthesis
The final electron acceptor associated with photosystem 1 is
NADP
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 of the following statements is true about the Krebs (citric acid) cycle and the Calvin (light-independent) cycle?
They both are carried out by enzymes located within an organelle matrix.
In a plant cell, where are the ATP synthase complexes located?
Thylakoid membrane and inner mitochondrial membrane
What event accompanies energy absorption by chlorophyll (or other pigment molecules of the antenna complex)?
What event accompanies energy absorption by chlorophyll (or other pigment molecules of the antenna complex)?
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. Additional observations were made on day 21, and no yellow-leaved seedlings were found alive in either dish. This is most likely because
Yellow-leaved seedlings were unable to convert light energy to chemical energy
Compared to C3 plants, C4 plants _____.
can continue to fix CO2 even at lower CO2 concentrations and higher oxygen concentrations
The carbon 'that makes up organic molecules in plants is derived directly from
carbon fixed in photosynthesis
In autumn, the leaves of deciduous trees change colors. This is because chlorophyll is degraded and _____
carotenoids and other pigments are still present in the leaves
CAM plants keep stomata closed in the daytime, thus reducing loss of water. They can do this because they _____.
fix CO2 into organic acids during the night
In autotrophic bacteria, where is chlorophyll located?
in the infolded plasma membrane
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
