BS 161 Exam 3 - Questions And Complete Answers
(Rated A+)
Which of the following sequences CORRECTLY represents the flow of energy
through living systems? Right Ans - light → photosynthesis → carbohydrate
→ cellular respiration → ATP → heat
Where is the photosynthetic electron transport chain located in plant cells?
Right Ans - in the thylakoid membranes of the chloroplast
In a thylakoid membrane, absorbed light energy is passed from one
chlorophyll molecule to another until it is: Right Ans - passed to a reaction
center.
During photosynthesis, _____ is reduced to _____. Right Ans - carbon dioxide;
sugar
Which of the following CORRECTLY lists the three steps of the Calvin cycle?
Right Ans - carboxylation, reduction, and regeneration
Which of the following CORRECTLY describes the role of rubisco in the Calvin
cycle? Right Ans - Rubisco incorporates CO2 from the atmosphere into an
organic molecule.
How many CO2 molecules must enter the Calvin cycle for each molecule of
triose phosphate that can be exported from the chloroplast? Right Ans - 3
In the Calvin cycle, NADPH is: Right Ans - oxidized.
Which step of the Calvin cycle would be affected first by a lack of NADPH?
Right Ans - reduction
Which of the following are products of the light-dependent reactions of
photosynthesis that are required by reactions in the Calvin cycle? Right
Ans - ATP and NADPH
, Which of the following are produced directly as a result of the movement of
electrons through the photosynthetic electron transport chain? Right Ans -
ATP and NADPH
During photosynthesis in plants and algae, _____ is being oxidized and _____ is
being reduced. Right Ans - H2O; CO2
In plants and algae, _____ is the source of the electrons needed for
photosynthesis. Right Ans - H2O
In plants and algae, which of the following is a by-product of photosynthesis?
Right Ans - O2
Which one of the following is NOT a product when photosystem II oxidizes a
molecule of water? Right Ans - carbon dioxide
Which of the following CORRECTLY lists the path taken by electrons through
the light dependent reactions of photosynthesis? Right Ans - water →
photosystem II → cytochrome b6f → photosystem I → NADPH
Why is the photosynthetic electron transport chain sometimes referred to as
the "Z scheme"? Right Ans - Because the energy level of the electrons
increases and decreases and increases and decreases.
As electrons flow through the light-dependent reactions, they become
associated with several molecules and molecular complexes. When do the
electrons have the GREATEST amount of energy? Right Ans - when they are
associated with photosystem I
As electrons flow from one photosystem to another, the amount of energy
present in the electrons decreases. How does the plant cell use the energy lost
by the electrons? Right Ans - The energy is used to create and maintain a
proton gradient.
In the chloroplast, cytochrome b6f is an important complex in the
photosynthetic electron transport chain because it accepts electrons from
photosystem II and donates them to photosystem I. Another vital function of
cytochrome b6f is that, during its reduction-oxidation cycle, it moves _____
from the _____. Right Ans - protons; stroma into the thylakoid lumen
(Rated A+)
Which of the following sequences CORRECTLY represents the flow of energy
through living systems? Right Ans - light → photosynthesis → carbohydrate
→ cellular respiration → ATP → heat
Where is the photosynthetic electron transport chain located in plant cells?
Right Ans - in the thylakoid membranes of the chloroplast
In a thylakoid membrane, absorbed light energy is passed from one
chlorophyll molecule to another until it is: Right Ans - passed to a reaction
center.
During photosynthesis, _____ is reduced to _____. Right Ans - carbon dioxide;
sugar
Which of the following CORRECTLY lists the three steps of the Calvin cycle?
Right Ans - carboxylation, reduction, and regeneration
Which of the following CORRECTLY describes the role of rubisco in the Calvin
cycle? Right Ans - Rubisco incorporates CO2 from the atmosphere into an
organic molecule.
How many CO2 molecules must enter the Calvin cycle for each molecule of
triose phosphate that can be exported from the chloroplast? Right Ans - 3
In the Calvin cycle, NADPH is: Right Ans - oxidized.
Which step of the Calvin cycle would be affected first by a lack of NADPH?
Right Ans - reduction
Which of the following are products of the light-dependent reactions of
photosynthesis that are required by reactions in the Calvin cycle? Right
Ans - ATP and NADPH
, Which of the following are produced directly as a result of the movement of
electrons through the photosynthetic electron transport chain? Right Ans -
ATP and NADPH
During photosynthesis in plants and algae, _____ is being oxidized and _____ is
being reduced. Right Ans - H2O; CO2
In plants and algae, _____ is the source of the electrons needed for
photosynthesis. Right Ans - H2O
In plants and algae, which of the following is a by-product of photosynthesis?
Right Ans - O2
Which one of the following is NOT a product when photosystem II oxidizes a
molecule of water? Right Ans - carbon dioxide
Which of the following CORRECTLY lists the path taken by electrons through
the light dependent reactions of photosynthesis? Right Ans - water →
photosystem II → cytochrome b6f → photosystem I → NADPH
Why is the photosynthetic electron transport chain sometimes referred to as
the "Z scheme"? Right Ans - Because the energy level of the electrons
increases and decreases and increases and decreases.
As electrons flow through the light-dependent reactions, they become
associated with several molecules and molecular complexes. When do the
electrons have the GREATEST amount of energy? Right Ans - when they are
associated with photosystem I
As electrons flow from one photosystem to another, the amount of energy
present in the electrons decreases. How does the plant cell use the energy lost
by the electrons? Right Ans - The energy is used to create and maintain a
proton gradient.
In the chloroplast, cytochrome b6f is an important complex in the
photosynthetic electron transport chain because it accepts electrons from
photosystem II and donates them to photosystem I. Another vital function of
cytochrome b6f is that, during its reduction-oxidation cycle, it moves _____
from the _____. Right Ans - protons; stroma into the thylakoid lumen
