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

• Calvin cycle (dark reactions)

• Inputs: water, carbon dioxide, light energy, NADP+, ADP

• Outputs: oxygen, ATP, NADPH, glucose (G3P)

Step-by-Step Guidance

1. List the main inputs for the light reactions (think about what is absorbed by the chloroplast during daylight).

2. Identify the main outputs of the light reactions and where they go (e.g., which are released, which are used in the next stage).

3. List the main inputs for the Calvin cycle (consider what is produced in the light reactions and what is taken from the environment).

4. Identify the main outputs of the Calvin cycle and their fate (e.g., what is exported from the chloroplast, what is recycled).

5. For each input and output, specify its source or destination (e.g., water from soil, oxygen to atmosphere, glucose to plant tissues).

Try solving on your own before revealing the answer!

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 inside chloroplasts

• Stroma: fluid-filled space surrounding thylakoids

• Light reactions, Calvin cycle

Step-by-Step Guidance

1. Recall which stage of photosynthesis occurs in the thylakoid membranes and what is produced there.

2. Identify the main processes that occur in the stroma and their products.

3. Think about why these processes are separated into different compartments.

Try solving on your own before revealing the answer!

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

Background

Topic: Photosynthetic Membranes

This question examines your understanding of how the thylakoid membrane contributes to the light-dependent reactions of photosynthesis.

Key Terms and Concepts:

• Photosystems I and II

• Electron transport chain

• Proton gradient

• ATP synthase

Step-by-Step Guidance

1. Describe how the thylakoid membrane houses the components necessary for the light reactions.

2. Explain how the movement of electrons along the membrane leads to the generation of a proton gradient.

3. Discuss how this gradient is used to produce ATP.

Try solving on your own before revealing the answer!

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 and Concepts:

• Photosynthesis: $6CO_2 + 6H_2O + \text{light energy} \rightarrow C_6H_{12}O_6 + 6O_2$

• Cellular respiration: $C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{energy}$

• Carbon cycle, oxygen cycle

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 are interconnected in the biosphere (e.g., cycling of oxygen and carbon dioxide).

4. Consider the ecological consequences of this relationship (e.g., energy flow, atmospheric composition).

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

Background

Topic: Light Reactions – Electron Flow

This question focuses on how the photosystems and electron transport chain work together to convert light energy into chemical energy.

Key Terms and Concepts:

• Photosystem II (PSII), Photosystem I (PSI)

• Electron transport chain (ETC)

• NADP+ reduction, ATP synthesis

Step-by-Step Guidance

1. Describe the sequence of events starting with light absorption by PSII.

2. Explain how electrons are transferred through the ETC and what is produced at each step.

3. Discuss the role of PSI in the process and how the electrons are ultimately used.

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Q6. How is the increased H+ concentration in the thylakoid generated?

Background

Topic: Chemiosmosis in Photosynthesis

This question tests your understanding of how a proton gradient is established during the light reactions.

Key Terms and Concepts:

• Water splitting (photolysis)

• Electron transport chain

• Proton pumps

Step-by-Step Guidance

1. Identify the source of protons (H+) in the thylakoid lumen.

2. Explain how the movement of electrons through the ETC contributes to proton accumulation.

3. Describe the role of water splitting at PSII in this process.

Try solving on your own before revealing the answer!

Q7. What is the role of ATP synthase in the light reaction and how does it compare to its role in cellular respiration?

Background

Topic: ATP Production in Cells

This question asks you to compare the function of ATP synthase in chloroplasts and mitochondria.

Key Terms and Concepts:

• ATP synthase

• Proton gradient

• Photophosphorylation vs. oxidative phosphorylation

Step-by-Step Guidance

1. Describe how ATP synthase uses the proton gradient to generate ATP in the chloroplast.

2. Compare this process to ATP generation in mitochondria during cellular respiration.

3. Highlight similarities and differences in the source of the proton gradient and the location of ATP synthesis.

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Q8. What does ‘carbon fixation’ refer to in the context of photosynthesis? When/where does it occur?

Background

Topic: Calvin Cycle – Carbon Fixation

This question tests your understanding of how inorganic carbon is incorporated into organic molecules during photosynthesis.

Key Terms and Concepts:

• Carbon fixation

• Calvin cycle

• RuBisCO enzyme

• Stroma of the chloroplast

Step-by-Step Guidance

1. Define carbon fixation in your own words.

2. Identify the enzyme responsible for this process and where it is located.

3. Describe when during photosynthesis carbon fixation occurs.

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Q9. Know what roots, shoots, and leaves are in a plant and what they do.

Background

Topic: Plant Anatomy

This question tests your knowledge of the basic organs of a plant and their functions.

Key Terms:

• Roots: anchor, absorb water/nutrients

• Shoots: stems and leaves, support, transport, photosynthesis

• Leaves: main site of photosynthesis

Step-by-Step Guidance

1. Define each organ (root, shoot, leaf) and its primary function.

2. Think about how these organs work together to support plant life.

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Q10. Know the three major tissue types in plants. Be able to identify where we would find these tissue types in roots, shoots, and leaves. In very general terms be able to describe their function.

Background

Topic: Plant Tissue Types

This question tests your understanding of dermal, ground, and vascular tissues and their distribution in plant organs.

Key Terms:

• Dermal tissue: protection

• Ground tissue: photosynthesis, storage, support

• Vascular tissue: transport (xylem and phloem)

Step-by-Step Guidance

1. List the three major tissue types and their general functions.

2. Identify where each tissue type is found in roots, shoots, and leaves.

3. Think about how the arrangement of these tissues supports plant function.

Try solving on your own before revealing the answer!