What process occurs when light energy causes electrons to be released from chlorophyll molecules in the thylakoid membrane?
Photoionisation
Light energy excites electrons in chlorophyll, causing them to leave the molecule.
What molecule acts as the final electron acceptor in the light-dependent reaction of photosynthesis?
NADP
When reduced, it forms reduced NADP (NADPH).
Fill in the blanks:
During the light-dependent reaction, NADP gains electrons and hydrogen ions to become ______ ______.
reduced NADP
Reduced NADP carries hydrogen to the Calvin cycle.
What membrane structure in chloroplasts contains the electron transfer chain used in the light-dependent reaction?
Thylakoid membrane
Chlorophyll, electron carriers and ATP synthase are embedded here.
What enzyme embedded in the thylakoid membrane catalyses ATP formation during chemiosmosis?
ATP synthase
Protons flow through this enzyme, driving ATP synthesis.
True or False:
Photolysis occurs in the stroma of the chloroplast.
False
Photolysis occurs at photosystem II in the thylakoid membrane.
What process splits water molecules using light energy during the light-dependent reaction?
Photolysis
Produces electrons, protons and oxygen.
Fill in the blank:
The splitting of water during photolysis releases oxygen, electrons and ______.
protons
These protons contribute to the proton gradient.
True or False:
The proton gradient across the thylakoid membrane drives ATP synthesis.
True
Proton movement through ATP synthase powers ATP production.
What theory explains how electron transport and proton movement drive ATP formation in chloroplasts?
Chemiosmotic theory
Involves proton gradients across membranes.
Which enzyme catalyses the fixation of carbon dioxide in the Calvin cycle?
Rubisco
Catalyses the reaction between CO2 and RuBP.
Fill in the blank:
In the Calvin cycle, carbon dioxide reacts with ______ to form two molecules of GP.
RuBP
RuBP stands for ribulose bisphosphate.
What three-carbon molecule is produced when CO2 reacts with RuBP in the Calvin cycle?
GP
GP stands for glycerate 3-phosphate.
What three-carbon molecule is produced when GP is reduced using ATP and reduced NADP?
Triose phosphate
Often abbreviated to TP.
True or False:
All triose phosphate molecules produced in the Calvin cycle are converted into glucose.
False
Some regenerate RuBP to keep the cycle running.
Fill in the blank:
Energy for reducing GP to triose phosphate is supplied by ______ and reduced NADP.
ATP
Both originate from the light-dependent reaction.
What stage of photosynthesis uses ATP and reduced NADP to produce carbohydrates?
Calvin cycle
Also known as the light-independent reaction.
True or False:
Carbon dioxide concentration can limit the rate of photosynthesis.
True
Low CO2 levels reduce the rate of carbon fixation.
Name one environmental factor, other than carbon dioxide, that can limit photosynthesis.
Light intensity
Temperature is another common limiting factor.
Why do commercial greenhouses often increase carbon dioxide levels?
It increase the photosynthesis rate.
Higher CO2 reduces limitation and boosts crop yield.
True or False:
Increasing temperature always increases the rate of photosynthesis indefinitely.
False
Above the optimum temperature, enzymes denature and the rate falls.
What laboratory technique is used to separate photosynthetic pigments extracted from leaves?
Chromatography
Used in required practical investigations of leaf pigments.
What type of organisms are commonly used to measure photosynthesis rate in school experiments with bubbles or oxygen production?
Aquatic plants
Examples include pondweed such as Elodea.
-
2: Biological Molecules119
-
2: Water & Inorganic Ions19
-
2: Cells52
-
2: Cell Division20
-
2: Membranes & Transport20
-
2: Exchange Surfaces37
-
2: Transport Systems39
-
2: Immune system36
-
2: Enzymes & Digestion16
-
3: Plant Transport20
-
4: Biodiversity & Classification32
-
4: Investigating Diversity12
-
4: Evolution42
-
4: Disease24
-
5: Photosynthesis23
-
5: Respiration17
-
5: Energy & Ecosystems35
-
5: Homeostasis57
-
5: Nervous & Hormonal Communication115
-
5: Muscles14
-
6: DNA & Protein Synthesis27
-
6: Meiosis & Genetic Diversity14
-
6: Inheritance12
-
6: Populations (Hardy–Weinberg)15
-
6: Ecosystems & Population Dynamics24
-
6: Gene Mutations & Expression58
-
6: Biotechnology & Genomics46
-
6: ATP & Energy Transfer (Integration)11
