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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1:05 minutes

Problem 14

Textbook Question

The following diagram compares the chemiosmotic synthesis of ATP in mitochondria and chloroplasts. Identify the components that are shared by both organelles and indicate which side of the membrane has the higher H+ concentration. Then label on the right the locations within the chloroplast.
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Verified step by step guidance

Step 1: Identify the shared components between mitochondria and chloroplasts. Both organelles use a membrane-bound ATP synthase enzyme to synthesize ATP, and both rely on a proton gradient (H+ concentration difference) across a membrane to drive this process.

Step 2: Determine which side of the membrane has the higher H+ concentration. In mitochondria, the intermembrane space has a higher H+ concentration compared to the matrix. In chloroplasts, the thylakoid lumen has a higher H+ concentration compared to the stroma.

Step 3: Label the components on the right side of the diagram for the chloroplast. 'c' corresponds to the thylakoid lumen, 'd' corresponds to the thylakoid membrane, and 'e' corresponds to the stroma.

Step 4: Understand the movement of protons. In both organelles, protons move down their concentration gradient through ATP synthase, from the side with higher H+ concentration to the side with lower H+ concentration, driving ATP synthesis.

Step 5: Relate the energy source for creating the proton gradient. In mitochondria, the energy comes from the electron transport chain powered by cellular respiration. In chloroplasts, the energy comes from the light-driven electron transport chain during photosynthesis.

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Key Concepts

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

Chemiosmosis

Chemiosmosis is the process by which ATP is produced in both mitochondria and chloroplasts through the movement of protons (H+) across a membrane. This movement occurs via ATP synthase, an enzyme that harnesses the energy from the proton gradient created by electron transport chains. The flow of protons back into the mitochondrial matrix or chloroplast stroma drives the conversion of ADP and inorganic phosphate into ATP.

Proton Gradient

A proton gradient is established when there is a difference in H+ ion concentration across a membrane. In mitochondria, this gradient is created during cellular respiration, while in chloroplasts, it occurs during photosynthesis. The side of the membrane with a higher concentration of H+ ions is crucial for ATP synthesis, as it drives protons through ATP synthase, facilitating ATP production.

Organellar Structures

Mitochondria and chloroplasts have distinct structures that facilitate their functions. Mitochondria have an inner membrane where the electron transport chain is located, while chloroplasts contain thylakoid membranes where light-dependent reactions occur. Understanding these structures is essential for identifying where ATP synthesis takes place and how the components of each organelle contribute to the overall process of energy conversion.

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Related Videos

Related Practice

Textbook Question

Predict how the following conditions would affect the production of O2, ATP, and NADPH and state whether noncyclic or cyclic electron flow would occur in each: (1) Only blue photons hit a chloroplast

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Textbook Question

Predict how the following conditions would affect the production of O₂, ATP, and NADPH and state whether noncyclic or cyclic electron flow would occur in each:

(1) Only blue photons hit a chloroplast

667

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Textbook Question

An investigator exposes chloroplasts to 700-nm photons and observes low O₂ production, but high ATP production. Which of the following best explains this observation?

a. The electrons from water are directly transferred to NADP⁺, which is used to generate ATP.

b. Photosystem II is not splitting water, and the ATP is being produced by cycling electrons via photosystem I.

c. The O₂ is being converted to water as a terminal electron acceptor in the production of ATP.

d. Electron transport has stopped and ATP is being produced by the Calvin cycle.

1050

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Textbook Question

Explain what is meant by saying the light reactions convert solar energy to chemical energy.

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Multiple Choice

Where do the light-dependent reactions of photosynthesis take place?