BIO 121 Unit 3 Study Guidance: Photosynthesis, Cellular Respiration, and Related Concepts

Study Guide - Smart Notes

Tailored notes based on your materials, expanded with key definitions, examples, and context.

Q1. What is the structure of a chloroplast, where are they found, and where is the chlorophyll and other pigments?

Background

Topic: Chloroplast Structure and Function

This question tests your understanding of the anatomy of chloroplasts, their location in plant cells, and the distribution of pigments involved in photosynthesis.

Key Terms:

Chloroplast: A double-membraned organelle found in plant cells and some protists, responsible for photosynthesis.
Thylakoid: Membranous sacs within the chloroplast where light-dependent reactions occur.
Stroma: The fluid-filled space surrounding the thylakoids, where the Calvin cycle takes place.
Chlorophyll: The main pigment involved in capturing light energy.

Step-by-Step Guidance

Identify where chloroplasts are located within plant cells (think about which cells and tissues contain them).
Describe the main structural components of a chloroplast (outer membrane, inner membrane, thylakoids, grana, stroma).
Explain where chlorophyll and other pigments are found within the chloroplast (focus on the thylakoid membranes).
Consider the functional significance of these locations for photosynthesis.

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Q2. Can I write out the equations for both photosynthesis and cellular respiration?

Background

Topic: Biochemical Equations

This question checks your ability to recall and write the overall chemical equations for photosynthesis and cellular respiration.

Key Equations:

Photosynthesis:
Cellular Respiration:

Step-by-Step Guidance

Recall the reactants and products for each process (think about what goes in and what comes out).
Write the balanced chemical equation for photosynthesis, including the energy input.
Write the balanced chemical equation for cellular respiration, showing the breakdown of glucose.
Compare the two equations to notice how they are essentially the reverse of each other.

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Q3. What is the job of the stomata in a leaf?

Background

Topic: Plant Anatomy and Gas Exchange

This question tests your understanding of how plants exchange gases with their environment and the role of stomata in this process.

Key Terms:

Stomata: Small openings on the underside of leaves that regulate gas exchange.
Guard Cells: Specialized cells that control the opening and closing of stomata.

Step-by-Step Guidance

Identify the main gases exchanged through the stomata (CO2, O2, and water vapor).
Explain how the opening and closing of stomata are regulated by guard cells.
Describe why stomatal regulation is important for photosynthesis and water conservation.

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Q4. Can I explain the steps in the light reactions and the steps in the Calvin cycle (with all the details that are in the ppt)?

Background

Topic: Photosynthesis Pathways

This question assesses your ability to describe the two main stages of photosynthesis: the light-dependent reactions and the Calvin cycle (light-independent reactions).

Key Concepts:

Light Reactions: Occur in the thylakoid membranes; convert light energy to chemical energy (ATP and NADPH).
Calvin Cycle: Occurs in the stroma; uses ATP and NADPH to fix carbon dioxide into organic molecules.

Step-by-Step Guidance

List the main steps of the light reactions, including the role of photosystems, electron transport chain, and production of ATP/NADPH.
Describe the inputs and outputs of the light reactions.
Outline the three phases of the Calvin cycle: carbon fixation, reduction, and regeneration of RuBP.
Identify the molecules entering and leaving the Calvin cycle.

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Q5. Do I understand that glucose is actually made outside of the Calvin cycle?

Background

Topic: Carbohydrate Synthesis in Photosynthesis

This question checks your understanding of where and how glucose is synthesized during photosynthesis.

Key Concepts:

The Calvin cycle produces G3P (glyceraldehyde-3-phosphate), not glucose directly.
Glucose is formed from G3P molecules through subsequent reactions in the cytoplasm.

Step-by-Step Guidance

Recall what the direct product of the Calvin cycle is (G3P).
Explain how G3P molecules are exported from the chloroplast to the cytoplasm.
Describe how two G3P molecules can be combined to form glucose outside the Calvin cycle.

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Q6. Do I know why C4 and CAM photosynthesis evolved?

Background

Topic: Adaptations in Photosynthesis

This question tests your understanding of the evolutionary pressures that led to the development of C4 and CAM photosynthetic pathways.

Key Concepts:

Photorespiration: A process that reduces the efficiency of photosynthesis, especially under hot, dry conditions.
C4 and CAM pathways help plants minimize photorespiration and water loss.

Step-by-Step Guidance

Describe the environmental conditions that favor the evolution of C4 and CAM pathways (e.g., high temperatures, arid climates).
Explain how these pathways help plants conserve water and reduce photorespiration.
Consider the selective advantages these adaptations provide in specific habitats.

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Q7. Do I know how C4 and CAM photosynthesis are different than C3 photosynthesis, and do I know how C4 and CAM are different than each other?

Background

Topic: Types of Photosynthetic Pathways

This question checks your ability to compare and contrast the three main types of photosynthesis: C3, C4, and CAM.

Key Concepts:

C3 Photosynthesis: The most common pathway; CO2 is fixed directly by rubisco in the Calvin cycle.
C4 Photosynthesis: CO2 is initially fixed in mesophyll cells, then transported to bundle sheath cells for the Calvin cycle.
CAM Photosynthesis: CO2 is fixed at night and stored as organic acids, then used during the day for the Calvin cycle.

Step-by-Step Guidance

Summarize the main steps of C3, C4, and CAM photosynthesis.
Identify the key differences in where and when CO2 fixation occurs in each pathway.
Explain how these differences help plants adapt to their environments.
Compare C4 and CAM pathways to each other, focusing on spatial vs. temporal separation of steps.

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Q8. Can I describe the three main parts of cellular respiration, including what enters and exits each part?

Background

Topic: Cellular Respiration Pathways

This question tests your knowledge of glycolysis, the Krebs cycle (citric acid cycle), and the electron transport chain.

Key Concepts:

Glycolysis: Occurs in the cytoplasm; breaks down glucose into pyruvate.
Krebs Cycle: Occurs in the mitochondrial matrix; processes pyruvate to produce electron carriers.
Electron Transport Chain: Occurs in the inner mitochondrial membrane; uses electrons to generate ATP.

Step-by-Step Guidance

List the three main stages of cellular respiration.
For each stage, identify the main inputs (substrates) and outputs (products).
Describe the role of electron carriers in transferring energy between stages.

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Q9. Do I know where in the cell the three parts of cellular respiration occur?

Background

Topic: Cellular Compartmentalization

This question checks your understanding of the cellular locations for glycolysis, the Krebs cycle, and the electron transport chain.

Key Concepts:

Glycolysis: Cytoplasm
Krebs Cycle: Mitochondrial matrix
Electron Transport Chain: Inner mitochondrial membrane

Step-by-Step Guidance

Recall the location of glycolysis in the cell.
Identify where the Krebs cycle takes place within the mitochondrion.
Determine the specific site of the electron transport chain.

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Q10. Do I know why fermentation may be used by a cell and why it’s not as good as cellular respiration? Can I name the two types of fermentation?

Background

Topic: Anaerobic Metabolism

This question tests your understanding of fermentation, its role in energy production, and its limitations compared to aerobic respiration.

Key Concepts:

Fermentation allows ATP production without oxygen but yields less energy than cellular respiration.
Two main types: lactic acid fermentation and alcoholic fermentation.

Step-by-Step Guidance

Explain why cells might need to use fermentation (e.g., lack of oxygen).
Compare the ATP yield of fermentation to that of cellular respiration.
Name and briefly describe the two main types of fermentation.

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Q11. Do I know the purpose of electron carriers?

Background

Topic: Electron Transport and Energy Transfer

This question checks your understanding of the role of molecules like NAD+, NADH, FAD, and FADH2 in cellular respiration and photosynthesis.

Key Terms:

Electron Carrier: A molecule that transports electrons during metabolic reactions.
NAD+/NADH, FAD/FADH2: Common electron carriers in cells.

Step-by-Step Guidance

Define what an electron carrier is and its general function.
Describe how electron carriers are reduced and oxidized during cellular respiration.
Explain why electron carriers are essential for ATP production.

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Q12. Do I know the one place in cellular respiration where oxygen is vital, and what happens to it once it is used?

Background

Topic: Role of Oxygen in Cellular Respiration

This question tests your understanding of the importance of oxygen in the electron transport chain and its fate after accepting electrons.

Key Concepts:

Oxygen acts as the final electron acceptor in the electron transport chain.
After accepting electrons, oxygen combines with protons to form water.

Step-by-Step Guidance

Identify the stage of cellular respiration where oxygen is required.
Explain the role of oxygen in the electron transport chain.
Describe what happens to oxygen after it accepts electrons and protons.

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Q13. Can I explain chemiosmosis?

Background

Topic: ATP Synthesis Mechanism

This question checks your understanding of how a proton gradient is used to generate ATP in both mitochondria and chloroplasts.

Key Terms:

Chemiosmosis: The movement of ions across a semipermeable membrane, down their electrochemical gradient, to drive ATP synthesis.
ATP Synthase: The enzyme that synthesizes ATP using the proton gradient.

Step-by-Step Guidance

Describe how the electron transport chain creates a proton gradient across a membrane.
Explain how protons flow back through ATP synthase.
Discuss how this flow of protons drives the production of ATP from ADP and inorganic phosphate.

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Q14. Can I name the reactions where ATP is produced, and do I know why ATP is so important to cells?

Background

Topic: ATP Production and Function

This question tests your knowledge of where ATP is generated in cellular respiration and photosynthesis, and the role of ATP in cellular processes.

Key Concepts:

ATP is produced during glycolysis, the Krebs cycle, and oxidative phosphorylation (chemiosmosis).
ATP is the main energy currency of the cell, used to power various cellular activities.

Step-by-Step Guidance

List the stages of cellular respiration and photosynthesis where ATP is produced.
Explain the importance of ATP for cellular work (e.g., transport, synthesis, movement).
Describe how ATP is generated in each stage (substrate-level phosphorylation vs. oxidative phosphorylation).

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Q15. Can I explain what rubisco is and what it does?

Background

Topic: Enzymes in Photosynthesis

This question checks your understanding of the enzyme rubisco and its role in the Calvin cycle.

Key Terms:

Rubisco: Ribulose-1,5-bisphosphate carboxylase/oxygenase, the enzyme that catalyzes the first step of carbon fixation in the Calvin cycle.

Step-by-Step Guidance

Define what rubisco is and its full name.
Describe the reaction that rubisco catalyzes in the Calvin cycle.
Explain why rubisco is considered both essential and inefficient.

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Q16. Can I briefly explain how molecules that are not carbohydrates are used in cellular respiration to generate ATP?

Background

Topic: Metabolic Pathways

This question tests your understanding of how proteins and fats can be metabolized to produce ATP.

Key Concepts:

Proteins are broken down into amino acids, which can enter the Krebs cycle after deamination.
Fats are broken down into glycerol and fatty acids; fatty acids undergo beta-oxidation to form acetyl-CoA.

Step-by-Step Guidance

Describe how proteins are processed for entry into cellular respiration.
Explain how fats are metabolized and which part of cellular respiration they enter.
Discuss why these alternative pathways are important for energy production.