Table of contents

1. Introduction to Biology2h 42m
2. Chemistry3h 37m
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
14. DNA Synthesis2h 27m
15. Gene Expression3h 6m
16. Regulation of Expression3h 31m
17. Viruses37m
- Viruses
  37m
18. Biotechnology2h 58m
19. Genomics17m
- Genomes
  17m
20. Development1h 5m
21. Evolution3h 1m
22. Evolution of Populations3h 53m
23. Speciation1h 37m
24. History of Life on Earth2h 6m
25. Phylogeny2h 31m
26. Prokaryotes4h 59m
27. Protists1h 12m
28. Plants1h 22m
29. Fungi36m
- Fungi
  19m
- Fungi Reproduction
  17m
30. Overview of Animals34m
- Overview of Animals
  34m
31. Invertebrates1h 2m
32. Vertebrates50m
33. Plant Anatomy1h 3m
34. Vascular Plant Transport1h 2m
- Water Potential
  1h 2m
35. Soil37m
- Soil and Nutrients
  20m
- Nitrogen Fixation
  16m
36. Plant Reproduction47m
- Flowers
  33m
- Seeds
  14m
37. Plant Sensation and Response1h 9m
38. Animal Form and Function1h 19m
39. Digestive System1h 10m
- Digestion
  1h 3m
- Blood Sugar Homeostasis
  7m
40. Circulatory System1h 49m
41. Immune System1h 12m
42. Osmoregulation and Excretion50m
- Osmoregulation and Excretion
  50m
43. Endocrine System1h 4m
- Endocrine System
  1h 4m
44. Animal Reproduction1h 2m
- Animal Reproduction
  1h 2m
45. Nervous System1h 55m
- Neurons and Action Potentials
  1h 8m
- Central and Peripheral Nervous System
  46m
46. Sensory Systems46m
- Sensory System
  46m
47. Muscle Systems23m
- Musculoskeletal System
  23m
48. Ecology3h 11m
49. Animal Behavior28m
- Animal Behavior
  28m
50. Population Ecology3h 41m
51. Community Ecology2h 46m
52. Ecosystems2h 36m
53. Conservation Biology24m
- Conservation Biology
  24m

9. Photosynthesis

Calvin Cycle

General Biology

9. Photosynthesis

Calvin Cycle

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0:53 minutes

Problem 7

Textbook Question

Apply what you know of the relationship between the light-capturing reactions and the Calvin cycle to calculate the number of photons used to produce a new G3P and regenerate RuBP. (Assume 1 ATP is produced for each pair of electrons used to form NADPH.)

Verified step by step guidance

Step 1: Understand the relationship between light-capturing reactions and the Calvin cycle. In the light-capturing reactions, light energy is used to produce ATP and NADPH. These are then used in the Calvin cycle to produce G3P and regenerate RuBP.

Step 2: Calculate the number of ATP and NADPH needed to produce a new G3P and regenerate RuBP. For each G3P molecule produced, 9 ATP and 6 NADPH are required. To regenerate RuBP, an additional 3 ATP are needed. So, a total of 12 ATP and 6 NADPH are needed.

Step 3: Calculate the number of photons needed to produce ATP and NADPH. Each ATP requires 2 photons, and each NADPH requires 2 photons (since 1 ATP is produced for each pair of electrons used to form NADPH). Therefore, 24 photons are needed for ATP and 12 photons for NADPH.

Step 4: Add the number of photons needed for ATP and NADPH to get the total number of photons used. So, 24 photons for ATP + 12 photons for NADPH = 36 photons.

Step 5: Therefore, 36 photons are used to produce a new G3P and regenerate RuBP.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Light-Capturing Reactions

The light-capturing reactions, also known as the light-dependent reactions, occur in the thylakoid membranes of chloroplasts. These reactions convert light energy into chemical energy in the form of ATP and NADPH. Photons are absorbed by chlorophyll, exciting electrons that are transferred through a series of proteins, ultimately leading to the production of ATP and NADPH, which are essential for the subsequent Calvin cycle.

Calvin Cycle

The Calvin cycle, or light-independent reactions, takes place in the stroma of chloroplasts and utilizes ATP and NADPH produced in the light-capturing reactions to convert carbon dioxide into glucose. The cycle involves three main phases: carbon fixation, reduction, and regeneration of RuBP. For every three molecules of CO2 that enter the cycle, one molecule of G3P is produced, which can be used to form glucose and other carbohydrates.

Photon Requirement for G3P Production

To produce one molecule of G3P, the Calvin cycle requires a specific number of ATP and NADPH, which are generated from the light-capturing reactions. Each pair of electrons used to form NADPH corresponds to the absorption of two photons, while ATP production is also linked to photon absorption. Therefore, calculating the total number of photons involves understanding the stoichiometry of ATP and NADPH used in the cycle, as well as their relationship to the number of G3P molecules produced.