WorksheetsPhotosynthesis Quiz
Total questions: 39
Worksheet time: 29mins
In photosynthesis, which molecule is oxidized?
Carbon dioxide (CO₂)
Water (H₂O)
Glucose
Oxygen (O₂)
The oxygen gas (O₂) released during photosynthesis comes from which reactant?
Carbon dioxide (CO₂)
Carbohydrate
Water (H₂O)
Light energy
During the reduction of CO₂ to form carbohydrates, carbon atoms:
Lose electrons
Gain electrons
Stay the same
Are converted to oxygen
In photosynthesis, the light energy absorbed by chlorophyll is used to:
Produce heat
Split CO₂
Split water and release electrons
Make oxygen directly
In photosystem II (PSII), the main event that starts photosynthesis is:
The splitting of CO₂
Absorption of light energy by pigments
Reduction of NADP⁺
Fixation of carbon
The absorption of light energy in PSII causes what to happen to electrons?
They are destroyed
They fall to a lower energy level
They are excited to a higher energy state
They combine with protons
In PSII, what molecule carries the high-energy electron away from the reaction center?
NADP⁺
ATP
PQ (plastoquinone)
FADH₂
What is the main purpose of the electron transport chain (ETC) after PSII?
To make NADPH directly
To pump protons and help form ATP
To fix CO₂ into sugar
To absorb more light
The enzyme that produces ATP during photosynthesis is called:
ATP lyase
ATP synthase
Rubisco
Kinase
Photosystem I (PSI) primarily functions to:
Split water molecules
Reduce NADP⁺ to NADPH
Generate oxygen
Fix carbon dioxide
What is the final electron acceptor in photosystem I?
Oxygen
Carbon dioxide
NADP⁺
PQ
The ATP and NADPH produced in the light-dependent reactions are used for:
Generating oxygen
Driving the Calvin cycle
Pumping protons
Splitting water
The Calvin cycle’s main function is to:
Split water molecules
Reduce CO₂ to produce sugars
Convert ATP to ADP
Release oxygen
The essence of photosynthesis is the conversion of:
Chemical energy to heat energy
Light energy to chemical energy in C–C and C–H bonds
Oxygen to carbon dioxide
ATP to NADPH
What are the discrete 'particles' of light that pigments absorb during photosynthesis called?
Electrons
Photons
Protons
Neutrons
Which wavelengths of visible light have the most energy?
Red wavelengths (~700 nm)
Green wavelengths (~550 nm)
Blue and purple wavelengths (~400 nm)
Yellow wavelengths (~600 nm)
In photosystem II (PSII), what molecule provides the replacement electrons for those excited by light?
Carbon dioxide (CO₂)
Glucose
Water (H₂O)
Oxygen (O₂)
When PSII splits water, what are the products of the reaction?
CO₂ and glucose
H₂ and O₂
4 H⁺, 4 e⁻, and O₂
NADPH and ATP
The oxygen (O₂) released during photosynthesis comes from:
Carbon dioxide (CO₂)
Water molecules split by PSII
The reduction of NADP⁺
The Calvin cycle
What is the ultimate purpose of the electron transport chain (ETC) following PSII?
To fix CO₂
To pump protons and generate ATP
To release oxygen
To absorb more photons
Why is the evolution of PSII considered one of the most important events in Earth’s history?
It allowed cells to use sulfur as an electron source
It released oxygen and changed Earth’s atmosphere
It led directly to the evolution of mitochondria
It increased Earth’s temperature
After electrons leave the electron transport chain (ETC), where do they go next?
Photosystem II (PSII)
Photosystem I (PSI)
The Calvin cycle
ATP synthase
Why are electrons that arrive at PSI at a low energy level?
They lost energy while pumping protons through the ETC
They were used to form ATP already
They absorbed too many photons
They reacted with oxygen
What happens when chlorophyll molecules in PSI absorb photons?
They split water molecules
They excite electrons to a higher energy state
They produce oxygen gas
They fix carbon dioxide
What is the main function of PSI in photosynthesis?
To produce ATP directly
To oxidize water
To reduce NADP⁺ to NADPH
To fix carbon dioxide
What role does NADPH play after it is formed?
It carries energy to the mitochondria
It helps reduce CO₂ in the Calvin cycle
It donates electrons to PSII
It releases oxygen during respiration
What enzyme uses the excited electrons from PSI to reduce NADP⁺?
ATP synthase
Rubisco
NADP⁺ reductase
Cytochrome complex
Sometimes, instead of reducing NADP⁺, PSI’s excited electrons are sent:
Back to PSII
To the ETC for additional proton pumping and ATP production
Directly to CO₂
Into mitochondria
What is the significance of PSI being able to send electrons either to NADP⁺ or back to the ETC?
It allows the cell to regulate the ratio of ATP to NADPH
It prevents oxygen from forming
It stops light absorption
It increases CO₂ levels
In plant and algal cells, photosynthesis takes place in which organelle?
Mitochondria
Nucleus
Chloroplast
Cytoplasm
How many outer membranes does a chloroplast have?
One
Two
Three
None
The inner membranes of chloroplasts form flattened sacs called:
Grana
Thylakoids
Vesicles
Lamellae
Stacks of thylakoids are called:
Grana
Stroma
Matrix
Vesicles
Where in the chloroplast are PSII, PSI, the ETC, and ATP synthase located?
In the stroma
In the thylakoid membranes
On the outer membrane
In the cytoplasm
What accumulates inside the thylakoid sacs during the light reactions?
ATP molecules
Protons (H⁺)
Oxygen gas
Carbon dioxide
The proton gradient inside thylakoids is used by:
Rubisco
ATP synthase
PSI directly
NADP⁺ reductase
The fluid-filled area surrounding the thylakoids is called the:
Cytoplasm
Stroma
Lumen
Grana
The organization of PSII, PSI, ETC, and ATP synthase in thylakoid membranes is functionally similar to:
The plasma membrane
The mitochondrial inner membrane
The nuclear envelope
The cell wall
What is the overall result of the thylakoid membrane structure and organization?
Oxygen and carbon dioxide mix evenly
A proton gradient forms to power ATP production
Light energy is absorbed only by PSII
Sugars are synthesized directly in the thylakoid
