Table of contents
- 1. Introduction to Biology2h 42m
- 2. Chemistry3h 40m
- 3. Water1h 26m
- 4. Biomolecules2h 23m
- 5. Cell Components2h 26m
- 6. The Membrane2h 31m
- 7. Energy and Metabolism2h 0m
- 8. Respiration2h 40m
- 9. Photosynthesis2h 49m
- 10. Cell Signaling59m
- 11. Cell Division2h 47m
- 12. Meiosis2h 0m
- 13. Mendelian Genetics4h 44m
- Introduction to Mendel's Experiments7m
- Genotype vs. Phenotype17m
- Punnett Squares13m
- Mendel's Experiments26m
- Mendel's Laws18m
- Monohybrid Crosses19m
- Test Crosses14m
- Dihybrid Crosses20m
- Punnett Square Probability26m
- Incomplete Dominance vs. Codominance20m
- Epistasis7m
- Non-Mendelian Genetics12m
- Pedigrees6m
- Autosomal Inheritance21m
- Sex-Linked Inheritance43m
- X-Inactivation9m
- 14. DNA Synthesis2h 27m
- 15. Gene Expression3h 20m
- 16. Regulation of Expression3h 31m
- Introduction to Regulation of Gene Expression13m
- Prokaryotic Gene Regulation via Operons27m
- The Lac Operon21m
- Glucose's Impact on Lac Operon25m
- The Trp Operon20m
- Review of the Lac Operon & Trp Operon11m
- Introduction to Eukaryotic Gene Regulation9m
- Eukaryotic Chromatin Modifications16m
- Eukaryotic Transcriptional Control22m
- Eukaryotic Post-Transcriptional Regulation28m
- Eukaryotic Post-Translational Regulation13m
- 17. Viruses37m
- 18. Biotechnology2h 58m
- 19. Genomics17m
- 20. Development1h 5m
- 21. Evolution3h 1m
- 22. Evolution of Populations3h 52m
- 23. Speciation1h 37m
- 24. History of Life on Earth2h 6m
- 25. Phylogeny2h 31m
- 26. Prokaryotes4h 59m
- 27. Protists1h 12m
- 28. Plants1h 22m
- 29. Fungi36m
- 30. Overview of Animals34m
- 31. Invertebrates1h 2m
- 32. Vertebrates50m
- 33. Plant Anatomy1h 3m
- 34. Vascular Plant Transport1h 2m
- 35. Soil37m
- 36. Plant Reproduction47m
- 37. Plant Sensation and Response1h 9m
- 38. Animal Form and Function1h 19m
- 39. Digestive System1h 10m
- 40. Circulatory System1h 57m
- 41. Immune System1h 12m
- 42. Osmoregulation and Excretion50m
- 43. Endocrine System1h 4m
- 44. Animal Reproduction1h 2m
- 45. Nervous System1h 55m
- 46. Sensory Systems46m
- 47. Muscle Systems23m
- 48. Ecology3h 11m
- Introduction to Ecology20m
- Biogeography14m
- Earth's Climate Patterns50m
- Introduction to Terrestrial Biomes10m
- Terrestrial Biomes: Near Equator13m
- Terrestrial Biomes: Temperate Regions10m
- Terrestrial Biomes: Northern Regions15m
- Introduction to Aquatic Biomes27m
- Freshwater Aquatic Biomes14m
- Marine Aquatic Biomes13m
- 49. Animal Behavior28m
- 50. Population Ecology3h 41m
- Introduction to Population Ecology28m
- Population Sampling Methods23m
- Life History12m
- Population Demography17m
- Factors Limiting Population Growth14m
- Introduction to Population Growth Models22m
- Linear Population Growth6m
- Exponential Population Growth29m
- Logistic Population Growth32m
- r/K Selection10m
- The Human Population22m
- 51. Community Ecology2h 46m
- Introduction to Community Ecology2m
- Introduction to Community Interactions9m
- Community Interactions: Competition (-/-)38m
- Community Interactions: Exploitation (+/-)23m
- Community Interactions: Mutualism (+/+) & Commensalism (+/0)9m
- Community Structure35m
- Community Dynamics26m
- Geographic Impact on Communities21m
- 52. Ecosystems2h 36m
- 53. Conservation Biology24m
9. Photosynthesis
C3, C4 & CAM Plants
Problem 8`
Textbook Question
How is photosynthesis similar in C4 plants and CAM plants? a. In both cases, the light reactions and the Calvin cycle are separated in both time and location. b. Both types of plants make sugar without the Calvin cycle. c. In both cases, rubisco is not used to fix carbon initially. d. Both types of plants make most of their sugar in the dark.

1
Understand the process of photosynthesis: Photosynthesis consists of two main stages—the light reactions and the Calvin cycle. The light reactions capture energy from sunlight, while the Calvin cycle uses that energy to fix carbon dioxide into sugars.
Learn about C4 plants: C4 plants have a specialized mechanism to minimize photorespiration. They initially fix carbon dioxide into a four-carbon compound using an enzyme called PEP carboxylase, which is more efficient than rubisco in low CO2 conditions. The Calvin cycle occurs in specialized bundle-sheath cells.
Learn about CAM plants: CAM plants also minimize photorespiration but do so by separating the processes of carbon fixation and the Calvin cycle in time. They fix carbon dioxide into a four-carbon compound at night when stomata are open, and then use it during the day for the Calvin cycle when stomata are closed.
Compare the similarities: Both C4 and CAM plants initially fix carbon dioxide using PEP carboxylase instead of rubisco, which helps them avoid photorespiration. This is a key similarity between the two types of plants.
Analyze the options: Based on the understanding of C4 and CAM plants, the correct answer is likely option c, as both types of plants initially fix carbon using PEP carboxylase rather than rubisco.

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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Photosynthesis
Photosynthesis is the process by which green plants, algae, and some bacteria convert light energy into chemical energy, specifically glucose, using carbon dioxide and water. This process occurs in two main stages: the light-dependent reactions, which capture energy from sunlight, and the light-independent reactions, or Calvin cycle, which synthesizes glucose. Understanding this process is crucial for comparing different plant adaptations.
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C4 and CAM Pathways
C4 and CAM (Crassulacean Acid Metabolism) are two adaptations that allow plants to efficiently fix carbon dioxide in environments with high temperatures and low water availability. C4 plants separate the initial carbon fixation and the Calvin cycle spatially, while CAM plants separate these processes temporally, fixing carbon at night. Both adaptations help minimize photorespiration and water loss, making them vital for survival in challenging conditions.
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Rubisco and Carbon Fixation
Rubisco (ribulose-1,5-bisphosphate carboxylase/oxygenase) is the enzyme responsible for fixing carbon dioxide in the Calvin cycle. In C4 and CAM plants, initial carbon fixation occurs through different mechanisms that do not involve Rubisco, allowing these plants to optimize carbon capture under specific environmental conditions. Understanding the role of Rubisco is essential for grasping how these plants adapt their photosynthetic processes.
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