BZ 440 EXAM 2 QUESTIONS WITH CORRECT ANSWERS LATEST UPDATE 2025-2026
Carbon enters the plant in the form of... - Answers CO2
Carbon is fixed by the enzyme... - Answers Rubisco
Carbon is coupled to_____ to form ______ - Answers RuBP, G3P (C3 sugar)
What is the Calvin Cycle and where does it take place? - Answers Carbon is fixed by Rubisco and
coupled to RuBP to form G3P. This takes place in the chloroplast stroma.
Describe chemiosmosis: - Answers Protons are pumped over the membrane, creating a proton
gradient. The protons flow back to the stroma via an ATP synthase, creating ATP
Photosythnesis is part of which branch of metabolism? - Answers Anabolism
What is the overall reaction of photosynthesis? - Answers CO2+H2O +Light => CH2O+O2
Photosynthesis is a redox reaction, what is reduced? What is oxidized? - Answers CO2 is
reduced to sugars and H2O is oxidized to O2
What molecule is used to shuttle electrons? (usually involved in anabolic processes) - Answers
NADP+
What are the two parts of photosynthesis? - Answers Light Reactions and Calvin Cycle
What molecules are used by Light Reactions? Calvin Cycle? - Answers ADP, NADP+. ATP,
NADPH.
Summarize the process that takes place in Light Reactions. - Answers Light energy is captured
by pigments. Part of this energy is stored in ATP, part is used to split H2O into O2, H+, and e-.
Summarize the process that takes place in the Calvin Cycle. - Answers CO2 is fixed by rubisco.
The CO2 is accepted by RuBP. Sugars are produced (3-CO2 in, 1-G3P out). ATP and NADPH are
used in this process.
What are the 3 phases of the Calvin Cycle? - Answers 1. CO2 fixation
2. Reduction
3. RuBP generation
Chlorophylls (a and b) - Answers Main pigments, essential for light capture.
Carotenoids (carotenes, xanthophylls) - Answers Essential in protection of plants from high
intensity light radiation, secondary role in light capture.
2 pigments involved in sunlight capture - Answers Chlorophylls and Carotenoids. They absorb
, wavelengths in the spectrum of visible light (PAR): λ = 400-700 nm. They reflect yellow and
green light, while absorb blue and red light.
What is a photsystem and how do they work? - Answers Cluster of pigments and proteins
working together to harvest light photons. 2 present: PSII and PSI. They work in series to
transfer e- from H2O to NADP+
Where is the reaction center chlorophyll found and what does it do? - Answers Found in each
photosystem. Transfers e- to the primary acceptor
Explain how ATP is synthesized during light reactions - Answers Through photophosphorylation.
e- flow through the ETC. The concentration of H+ increases in the lumen of the thylakoids
because: 1. H+ are pumped over thylakoid membranes from the stroma to the lumen (using E
from e- transport); 2. splitting of water releases more H+ in lumen; 3. synthesis of NADPH
lowers H+ in stroma. This leads to a H+ GRADIENT OVER THE THYLAKOID MEMBRANE. H+
diffuse back from lumen to stroma through ATP sythase => ATP produced.
What are 3 ways plants regulate light reactions? - Answers 1. Cyclic flow of e-
2. Light Harvesting Complex
3. Xantophyll cycle
What strategy is used when cells need to produce extra ATP and how does it work? - Answers
Cyclic flow of e-. Fd gives electrons back to Pq. This can happen at the same time as non-cyclic
photophosphorylation.
Explain the LHC - Answers Light Harvesting Complex. Can be attached or detached to/from
photosystems depending on light intensity.
Explain the xantopyll cycle - Answers Xantophyll pigments absorb excess light from chlorophylls
and dissipate it as heat.
What happens if the e- flow is blocked? - Answers Production of ROS. No production of ATP and
NADPH. Leads to death.
What is the main purpose of the Calvin cycle? - Answers Carbon Assimilation
Input and output of the Calvin cycle - Answers Input: 3 CO2
Output: 1 G3P
E Use: 9 ATP + 6 NADPH
Photorespiration - Answers Production of CO2, consumption of O2 and ATP during the Calvin
cycle (because Rubisco can bind both CO2 and O2). Causes reduction in plant productivity due
to the decrease of sugar production in Calvin cycle
Carbon enters the plant in the form of... - Answers CO2
Carbon is fixed by the enzyme... - Answers Rubisco
Carbon is coupled to_____ to form ______ - Answers RuBP, G3P (C3 sugar)
What is the Calvin Cycle and where does it take place? - Answers Carbon is fixed by Rubisco and
coupled to RuBP to form G3P. This takes place in the chloroplast stroma.
Describe chemiosmosis: - Answers Protons are pumped over the membrane, creating a proton
gradient. The protons flow back to the stroma via an ATP synthase, creating ATP
Photosythnesis is part of which branch of metabolism? - Answers Anabolism
What is the overall reaction of photosynthesis? - Answers CO2+H2O +Light => CH2O+O2
Photosynthesis is a redox reaction, what is reduced? What is oxidized? - Answers CO2 is
reduced to sugars and H2O is oxidized to O2
What molecule is used to shuttle electrons? (usually involved in anabolic processes) - Answers
NADP+
What are the two parts of photosynthesis? - Answers Light Reactions and Calvin Cycle
What molecules are used by Light Reactions? Calvin Cycle? - Answers ADP, NADP+. ATP,
NADPH.
Summarize the process that takes place in Light Reactions. - Answers Light energy is captured
by pigments. Part of this energy is stored in ATP, part is used to split H2O into O2, H+, and e-.
Summarize the process that takes place in the Calvin Cycle. - Answers CO2 is fixed by rubisco.
The CO2 is accepted by RuBP. Sugars are produced (3-CO2 in, 1-G3P out). ATP and NADPH are
used in this process.
What are the 3 phases of the Calvin Cycle? - Answers 1. CO2 fixation
2. Reduction
3. RuBP generation
Chlorophylls (a and b) - Answers Main pigments, essential for light capture.
Carotenoids (carotenes, xanthophylls) - Answers Essential in protection of plants from high
intensity light radiation, secondary role in light capture.
2 pigments involved in sunlight capture - Answers Chlorophylls and Carotenoids. They absorb
, wavelengths in the spectrum of visible light (PAR): λ = 400-700 nm. They reflect yellow and
green light, while absorb blue and red light.
What is a photsystem and how do they work? - Answers Cluster of pigments and proteins
working together to harvest light photons. 2 present: PSII and PSI. They work in series to
transfer e- from H2O to NADP+
Where is the reaction center chlorophyll found and what does it do? - Answers Found in each
photosystem. Transfers e- to the primary acceptor
Explain how ATP is synthesized during light reactions - Answers Through photophosphorylation.
e- flow through the ETC. The concentration of H+ increases in the lumen of the thylakoids
because: 1. H+ are pumped over thylakoid membranes from the stroma to the lumen (using E
from e- transport); 2. splitting of water releases more H+ in lumen; 3. synthesis of NADPH
lowers H+ in stroma. This leads to a H+ GRADIENT OVER THE THYLAKOID MEMBRANE. H+
diffuse back from lumen to stroma through ATP sythase => ATP produced.
What are 3 ways plants regulate light reactions? - Answers 1. Cyclic flow of e-
2. Light Harvesting Complex
3. Xantophyll cycle
What strategy is used when cells need to produce extra ATP and how does it work? - Answers
Cyclic flow of e-. Fd gives electrons back to Pq. This can happen at the same time as non-cyclic
photophosphorylation.
Explain the LHC - Answers Light Harvesting Complex. Can be attached or detached to/from
photosystems depending on light intensity.
Explain the xantopyll cycle - Answers Xantophyll pigments absorb excess light from chlorophylls
and dissipate it as heat.
What happens if the e- flow is blocked? - Answers Production of ROS. No production of ATP and
NADPH. Leads to death.
What is the main purpose of the Calvin cycle? - Answers Carbon Assimilation
Input and output of the Calvin cycle - Answers Input: 3 CO2
Output: 1 G3P
E Use: 9 ATP + 6 NADPH
Photorespiration - Answers Production of CO2, consumption of O2 and ATP during the Calvin
cycle (because Rubisco can bind both CO2 and O2). Causes reduction in plant productivity due
to the decrease of sugar production in Calvin cycle
