Biol 2170 Chapt 8 LS and Pre Assignment

For every six CO2 molecules incorporated into carbohydrate molecules, how many triose phosphates can be exported from the chloroplast? 2 12 10 6 1

2

For every six CO2 molecules incorporated into carbohydrate molecules, how many triose phosphates can be exported from the chloroplast? 2 12 1 6 10

2 Triose phosphate is a 3-carbon sugar, so six CO2 molecules would yield 2 triose phosphate molecules

Xanthophyll pigments: prevent formation of reactive oxygen species. absorb light energy. convert light energy into heat. reflect yellow light.

All of these choices are correct.

Which of the following is/are rubisco substrates?O2 CO2 and RuBP CO2 CO2, O2, and RuBP RuBP

CO2, O2, and RuBP

How many molecules of NADPH are required for 12 molecules of RuBP to be carboxylated by rubisco? 10 24 36 12 None of the other answer options is correct.

None of the other answer options is correct.

How many molecules of NADPH are required for 12 molecules of RuBP to be carboxylated by rubisco? 10 36 24 12 None of the other answer options is correct.

None of the other answer options is correct.

The regeneration of RuBP typically limits the rate of photosynthesis under low light intensities. This is because: RuBP regeneration requires ADP. RuBP regeneration is part of the "dark reactions." photosynthesis occurs only in high light. None of these answer choices is correct. RuBP regeneration requires ATP.

RuBP regeneration requires ATP.

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

T

Which statement is true regarding the earliest photosynthetic organisms on Earth? The organisms likely used molecules other than H2O (that is, H2S) as electron donors. Given the abundance of H2O on early Earth, these organisms used H2O as an electron donor. These organisms likely possessed two photosystems. These organisms likely used both inorganic molecules and H2O as electron donors. The organisms likely produced O2 as a waste product, resulting in Earth's current atmosphere.

The organisms likely used molecules other than H2O (that is, H2S) as electron donors.

A researcher is carrying out an experiment where she labels a protein with a fluorescent tag (so she can visualize its location in a cell) and introduces this tagged protein into the lumen of a single thylakoid. She observes her treated cells periodically and notices that the labeled protein can move between grana and is always in the lumen, but is never observed in the stroma. What can she deduce? The protein becomes part of the thylakoid membrane itself and moves freely throughout the interconnected membranes. This protein easily diffuses through the thylakoid membrane. The protein likely travels through a common lumen shared by thylakoid membranes and grana, and cannot easily diffuse through the thylakoid membrane. This protein likely travels between different thylakoid membranes by moving through the stroma, but its movement through the stroma is very brief. This protein can easily transfer between the inner and outer mitochondria membranes.

The protein likely travels through a common lumen shared by thylakoid membranes and grana, and cannot easily diffuse through the thylakoid membrane.

A researcher is carrying out an experiment where she labels a protein with a fluorescent tag (so she can visualize its location in a cell) and introduces this tagged protein into the lumen of a single thylakoid. She observes her treated cells periodically and notices that the labeled protein can move between grana and is always in the lumen, but is never observed in the stroma. What can she deduce? The protein becomes part of the thylakoid membrane itself and moves freely throughout the interconnected membranes. This protein easily diffuses through the thylakoid membrane. The protein likely travels through a common lumen shared by thylakoid membranes and grana, and cannot easily diffuse through the thylakoid membrane. This protein likely travels between different thylakoid membranes by moving through the stroma, but its movement through the stroma is very brief. This protein can easily transfer between the inner and outer mitochondria membranes.

The protein likely travels through a common lumen shared by thylakoid membranes and grana, and cannot easily diffuse through the thylakoid membrane.

Which of the following is true when comparing the Calvin cycle and light-harvesting reactions of photosynthesis? Please choose the correct answer from the following choices, and then select the submit answer button. They take place in different types of cells in the plant. They take place in different compartments of the same organelle. None of the other answer options is correct. They take place in different organelles.

They take place in different compartments of the same organelle.

Which of the following is true when comparing the Calvin cycle and light-harvesting reactions of photosynthesis? They take place in different types of cells in the plant. They take place in different compartments of the same organelle. None of the other answer options is correct. They take place in different organelles.

They take place in different compartments of the same organelle.

From its ground state, photosystem II can: absorb light energy. pull protons from H2O. pass electrons to photosystem I. pull electrons from H2O. emit light energy.

absorb light energy

Which of the answer choices correctly lists the three phases of the Calvin cycle? carboxylation, reduction, and regeneration reduction of CO2, reduction of NADPH, regeneration of RuBP oxidation, reduction, and carboxylation carboxylation, ATP synthesis, and regeneration

carboxylation, reduction, and regeneration

Which of these correctly lists the three phases of the Calvin cycle? reduction of CO2, reduction of NADPH, regeneration of RuBP carboxylation, ATP synthesis, and regeneration oxidation, reduction, and carboxylation carboxylation, reduction, and regeneration

carboxylation, reduction, and regeneration

How does the metabolism occurring in chloroplasts differ from that of mitochondria? different electron acceptors and electron sources None of the other answer options is correct. one makes ATP, the other makes NADPH different proton acceptors different proton sources

different electron acceptors and electron sources

The process in which one cell takes up residence in another cell is called: exocytosis. endocytosis. endosymbiosis. parasitism. commensalism

endosymbiosis

Antennae work with reaction centers by providing: electron transfer. H+ transfer. heat loss. energy transfer. fluorescence.

energy transfer.

During photorespiration, the phosphoglycolate (PGO) produced by RuBP oxygenation is eventually converted to phosphoglycerate (PGA); 75% of the carbon in PGO is recovered. How many molecules of PGO are required to generate two molecules of PGA through this route? one four five two three

four

From where does the oxygen come that is produced as a by-product of photosynthesis? from the Calvin cycle from the breakdown of carbohydrates from the breakdown of water from the reduction of CO2

from the breakdown of water

Which of the answer choices could likely result in a reduction of energy losses to photorespiration in plants? increased O2 concentration decreased H2O supply decreased light intensity decreased CO2 concentration increased CO2 concentration

increased CO2 concentration CO2 and O2 compete for rubisco, so an increase in CO2 would decrease photorespiratory losses.

In addition to chlorophylls, light-harvesting antennae include other pigments. What is the benefit of these additional pigments? increased range of wavelengths absorbed increased structural stability of the antennae enhanced resonance transfer tighter binding of the antennae to the thylakoid lower antioxidant capacity

increased range of wavelengths absorbed

With the endosymbiotic hypothesis in mind, what structure within modern-day chloroplasts is likely derived from the plasma membrane of ancestral cyanobacteria that took up residence within a eukaryotic cell? thylakoid membrane inner membrane stroma grana lumen

inner membrane Consider a food vacuole that results from endocytosis of a cyanobacterium by a eukaryotic cell as shown in the figure. If the endosymbiotic hypothesis is correct, then a) early eukaryotic cells that lived by endocytosis must have lost the ability to digest the engulfed cyanobacteria, b) the engulfed cyanobacteria must have gained the ability to resist digestion, or c) a combination of these two events occurred. The host cell membrane around the food vacuole would thus have become the origin of the outer membrane, and the plasma membrane of the cyanobacteria would then have been the origin of the inner membrane.

ATP production in photosynthesis requires: light, electrons, and protons. electrons only. protons only. light and protons only. light only.

light, electrons, and protons

NADPH production in photosynthesis requires: protons only. light and protons only. electrons only. light, electrons, and protons. light only.

light, electrons, and protons

ATP production in photosynthesis requires: protons only. electrons only. light only. light and protons only. light, electrons, and protons.

light, electrons, and protons.

Reactive oxygen species are detoxified in order to: All of these choices are correct. enhance linear electron transport. enhance cyclic electron transport. recover electrons. minimize damage to membranes.

minimize damage to membranes.

Many photosynthetic prokaryotes are capable of cyclic electron transport only. It is likely that such organisms can _____ but not _____. produce NADPH; oxidize H2O produce NADPH; reduce CO2 reduce CO2; synthesize carbohydrates produce ATP; reduce CO2 produce ATP; reduce H2O

produce ATP; reduce CO2 Such prokaryotes would not produce the NADPH required for CO2 reduction. Cyclic electron transport does result in pumping protons into the thylakoid lumen, however, and thus yields ATP.

Organisms with only one photosystem cannot: produce O2. reduce CO2. reduce NADP+. oxidize H2S. reduce H2O.

produce O2.

The occurrence of photorespiration _____ CO2 and _____ ATP. oxidizes; produces produces; produces produces; consumes reduces; produces consumes; consumes

produces; consumes

Rubisco is characterized by: fast catalysis. the ability to use three substrates. slow catalysis and the ability to use two substrates. the ability to use three substrates and faster catalysis.

slow catalysis and the ability to use two substrates.

With the endosymbiotic hypothesis in mind, what structure within modern-day chloroplasts is likely derived from the cytoplasm of an ancestral cyanobacterium that took up residence within a eukaryotic cell? thylakoid membrane grana stroma inner chloroplast membrane thylakoid lumen

stroma The chloroplast is believed to have arisen from an engulfed ancestral cyanobacterium, and thus the stroma would be derived from the cytoplasm of ancestral cyanobacterium.

The stroma of the land-plant chloroplast is evolutionarily derived from: the thylakoid membrane. the plasma membrane of cyanobacteria. the plasma membrane of a eukaryotic ancestor. the cytoplasm of cyanobacteria.

the cytoplasm of cyanobacteria.

Photorespiration and cellular respiration are alike because: Please choose the correct answer from the following choices, and then select the submit answer button. they both use photons instead of electrons to generate ATP. they both are reactions that consume O2 and release CO2. they both create H2O by reducing O2. they both are reactions that consume CO2 and release O2. they both happen in the light.

they both are reactions that consume O2 and release CO2.

In the chloroplasts of plant cells, the absorption of light energy and the movement of electrons along an electron transport chain occur in the _____, and the synthesis of carbohydrates takes place in the _____. inner membrane; cytoplasm thylakoids; stroma inner membrane; stroma thylakoids; matrix inner membrane; matrix

thylakoids; stroma

Photosystem I is a _____ than photosystem II. weaker oxidant and weaker reductant weaker oxidant and a stronger reductant weaker reductant stronger oxidant and a stronger reductant stronger oxidant

weaker oxidant and a stronger reductant