Skip to main content
Pearson+ LogoPearson+ Logo
Ch. 10 - Photosynthesis
All textbooksFreeman 8th EditionCh. 10 - PhotosynthesisProblem 9b
Chapter 10, Problem 9b

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;(2) blue and red photons hit a chloroplast, but no NADP+ is available

Verified step by step guidance
1
Step 1: Understand the process of photosynthesis. Photosynthesis is a process that converts light energy into chemical energy in plants. It involves two stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The light-dependent reactions occur in the thylakoid membrane of the chloroplasts and produce ATP, NADPH, and O2. The light-independent reactions use the ATP and NADPH to convert CO2 into glucose.
Step 2: Understand the role of NADP+. NADP+ is a coenzyme that accepts electrons during the light-dependent reactions to become NADPH. NADPH then carries these high-energy electrons to the Calvin cycle, where they are used to convert CO2 into glucose.
Step 3: Understand the role of light in photosynthesis. Blue and red photons are the most effective at driving photosynthesis. They are absorbed by chlorophyll pigments in the chloroplasts, which then use this energy to drive the light-dependent reactions.
Step 4: Predict the effect of the given conditions. If blue and red photons hit a chloroplast but no NADP+ is available, the light-dependent reactions can still occur, but the electrons from the chlorophyll cannot be transferred to NADP+ to form NADPH. This means that NADPH production would stop. However, ATP can still be produced through cyclic electron flow, where the electrons are recycled back into the photosystem. O2 production would also stop because it is a byproduct of noncyclic electron flow, which cannot occur without NADP+.
Step 5: Summarize the effects. In the given conditions, the production of O2 and NADPH would stop, but ATP production would continue through cyclic electron flow.

Verified Solution

Video duration:
2m
This video solution was recommended by our tutors as helpful for the problem above.
Was this helpful?

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, primarily in the form of glucose. This process occurs in chloroplasts and involves two main stages: the light-dependent reactions and the light-independent reactions (Calvin cycle). The light-dependent reactions generate ATP and NADPH, which are essential for the synthesis of glucose during the Calvin cycle.
Recommended video:
Guided course
05:58
Pigments of Photosynthesis

Electron Transport Chain

The electron transport chain (ETC) is a series of protein complexes located in the thylakoid membrane of chloroplasts that facilitate the transfer of electrons derived from light energy. As electrons move through the chain, they release energy used to pump protons into the thylakoid lumen, creating a proton gradient. This gradient drives ATP synthesis and is crucial for the production of NADPH when NADP+ is available to accept electrons.
Recommended video:
Guided course
07:41
Electron Transport Chain

Cyclic vs. Noncyclic Electron Flow

Cyclic and noncyclic electron flow are two pathways of electron transport during the light-dependent reactions of photosynthesis. Noncyclic electron flow involves both photosystems I and II, producing ATP, NADPH, and O2. In contrast, cyclic electron flow only involves photosystem I, resulting in the production of ATP without NADPH or O2. The availability of NADP+ influences which pathway occurs; without NADP+, cyclic flow is favored to continue ATP production.
Recommended video:
Guided course
03:21
Electron Source: Lithotrophs vs. Organotrophs
Related Practice
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.)

472
views
Textbook Question

Which of the following correctly identify a role of the ATP produced in the light-capturing reactions? Select True or False for each statement. T/F It is used by rubisco to fix CO2 to RuBP. T/F It serves the same role as ATP produced by mitochondria. T/F It is used to regenerate RuBP from G3P molecules. T/F It is used to produce G3P molecules

671
views
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

354
views
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;(3) blue and red photons hit a chloroplast, but a proton channel has been introduced into the thylakoid membrane, so it is fully permeable to protons.

636
views
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.

613
views