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

Light Reactions of Photosynthesis

General Biology

9. Photosynthesis

Light Reactions of Photosynthesis

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1:30 minutes

Problem 1

Textbook Question

Add labels to the figure that follows, which illustrates the product and reactants of photosynthesis and the relationship between its light reactions and light-independent reactions.

Verified step by step guidance

Identify the main components involved in photosynthesis: the chloroplast, thylakoid, stroma, light energy, CO2, O2, ATP, and NADP+.

Label the thylakoid as the site where light-dependent reactions occur, capturing light energy to produce ATP and NADPH.

Label the stroma as the site where light-independent reactions (Calvin cycle) occur, using ATP and NADPH to convert CO2 into glucose.

Indicate the input of light energy into the thylakoid and the production of O2 as a byproduct of the light-dependent reactions.

Show the flow of ATP and NADPH from the thylakoid to the stroma, where they are used in the light-independent reactions to fix CO2 into organic molecules.

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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 biochemical process by which green plants, algae, and some bacteria convert light energy into chemical energy, specifically glucose. This process occurs primarily in chloroplasts and involves two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The overall equation for photosynthesis can be summarized as 6CO2 + 6H2O + light energy → C6H12O6 + 6O2.

Light-dependent Reactions

Light-dependent reactions occur in the thylakoid membranes of chloroplasts and require light to produce ATP and NADPH. During these reactions, light energy is absorbed by chlorophyll, leading to the splitting of water molecules (photolysis), which releases oxygen as a byproduct. The energy captured is then used to convert ADP and NADP+ into their energized forms, ATP and NADPH, which are essential for the subsequent light-independent reactions.

Light-independent Reactions (Calvin Cycle)

The light-independent reactions, also known as the Calvin cycle, take place in the stroma of chloroplasts and do not require light directly. Instead, they utilize ATP and NADPH produced in the light-dependent reactions to convert carbon dioxide (CO2) into glucose through a series of enzymatic reactions. This cycle is crucial for synthesizing organic compounds that serve as energy sources for the plant and, ultimately, for other organisms in the ecosystem.