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

Introduction to Photosynthesis

General Biology

9. Photosynthesis

Introduction to Photosynthesis

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Multiple Choice

Why was the evolution of photosynthesizing bacteria important to most modern organisms?

They directly provided glucose to all multicellular organisms.

They released oxygen into the atmosphere, enabling aerobic respiration.

They increased the amount of carbon dioxide in the atmosphere.

They caused the extinction of all anaerobic organisms.

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Verified step by step guidance

Understand the role of photosynthesizing bacteria in Earth's history: Photosynthesizing bacteria, such as cyanobacteria, were among the first organisms to perform photosynthesis, a process that converts light energy into chemical energy while releasing oxygen as a byproduct.

Recognize the significance of oxygen release: Photosynthesizing bacteria released oxygen into the atmosphere, which was previously low in oxygen. This process, known as the Great Oxygenation Event, transformed Earth's atmosphere and made it suitable for aerobic organisms.

Connect oxygen release to aerobic respiration: Aerobic respiration is a process used by most modern organisms to efficiently produce energy (ATP) using oxygen. The oxygen released by photosynthesizing bacteria enabled the evolution of aerobic organisms, which rely on oxygen for survival.

Clarify why glucose is not directly provided: Photosynthesizing bacteria produce glucose for their own use during photosynthesis, but they do not directly provide glucose to multicellular organisms. Instead, they contribute to the ecosystem by producing oxygen and serving as a food source for other organisms.

Address the extinction of anaerobic organisms: While the increase in atmospheric oxygen caused some anaerobic organisms to decline, many anaerobic organisms adapted to survive in low-oxygen environments. Photosynthesizing bacteria did not cause the extinction of all anaerobic organisms.