Comprehensive Study Guidance for Biology 104 Exam 3 Topics

Q1. What are the inputs and outputs of the light reactions and the Calvin cycle? Where do the inputs come from? Where do the outputs go?

Background

Topic: Photosynthesis (Light Reactions and Calvin Cycle)

This question tests your understanding of the two main stages of photosynthesis, including the substances required and produced in each stage, and the flow of energy and matter through the process.

Key Terms and Concepts:

• Light reactions: Occur in the thylakoid membranes, use light energy to produce ATP and NADPH.

• Calvin cycle: Occurs in the stroma, uses ATP and NADPH to fix carbon dioxide into sugars.

• Inputs: Substances required for each stage (e.g., water, CO2, light).

• Outputs: Products generated (e.g., O2, glucose, NADP+).

Step-by-Step Guidance

1. List the main reactants (inputs) and products (outputs) for the light reactions. Consider where each comes from (e.g., water from the environment, light from the sun).

2. Identify the main reactants and products for the Calvin cycle. Think about how the products of the light reactions are used here.

3. For each input and output, specify its source or destination (e.g., O2 released to atmosphere, glucose used by plant).

4. Consider how the two stages are connected by the flow of ATP and NADPH.

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Q2. What happens in the thylakoid vs. what happens in the stroma of the chloroplast?

Background

Topic: Chloroplast Structure and Function

This question focuses on the compartmentalization of photosynthetic processes within the chloroplast and the specific roles of the thylakoid and stroma.

Key Terms:

• Thylakoid: Membrane-bound sacs where light reactions occur.

• Stroma: Fluid-filled space surrounding thylakoids, site of the Calvin cycle.

Step-by-Step Guidance

1. Recall which stage of photosynthesis occurs in each compartment.

2. Identify the main processes and molecules involved in each location (e.g., electron transport chain in thylakoid, carbon fixation in stroma).

3. Think about how the products of one compartment are used in the other.

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Q3. What is the role of the thylakoid membrane in photosynthesis?

Background

Topic: Photosynthetic Membranes

This question examines your understanding of the structural and functional importance of the thylakoid membrane in the light-dependent reactions of photosynthesis.

Key Terms:

• Thylakoid membrane: Contains chlorophyll, electron transport chain, and ATP synthase.

• Proton gradient: Essential for ATP synthesis.

Step-by-Step Guidance

1. Describe the components embedded in the thylakoid membrane (e.g., photosystems, electron carriers).

2. Explain how the membrane helps generate a proton gradient.

3. Connect the proton gradient to ATP synthesis via chemiosmosis.

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Q4. How do the inputs and outputs of cellular respiration and photosynthesis ‘match up’ with one another? What are the consequences of this for the biosphere?

Background

Topic: Relationship Between Photosynthesis and Cellular Respiration

This question tests your ability to compare and contrast the two processes and understand their ecological significance.

Key Terms:

• Photosynthesis: Converts CO2 and H2O into glucose and O2.

• Cellular respiration: Converts glucose and O2 into CO2 and H2O.

• Biosphere: The global sum of all ecosystems.

Step-by-Step Guidance

1. Write out the overall equations for both photosynthesis and cellular respiration.

2. Compare the reactants and products of each process.

3. Discuss how these processes cycle matter and energy in ecosystems.

4. Consider the broader implications for life on Earth (e.g., oxygen availability, carbon cycling).

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Q5. What is the relationship between the electron transport chain and the photosystems of photosynthesis?

Background

Topic: Light Reactions of Photosynthesis

This question focuses on how energy from light is transferred through photosystems and the electron transport chain to produce ATP and NADPH.

Key Terms:

• Photosystem II and I: Protein complexes that absorb light and transfer electrons.

• Electron transport chain (ETC): Series of molecules that pass electrons and pump protons.

Step-by-Step Guidance

1. Identify the sequence of events starting from light absorption in photosystem II.

2. Describe how electrons move through the ETC and reach photosystem I.

3. Explain how this movement is coupled to proton pumping and ATP/NADPH production.

Try solving on your own before revealing the answer!