General Biology Exam 3 Review: Energy, Photosynthesis, and Cellular Respiration

Q1. What are the two basic energy laws (laws of thermodynamics)?

Background

Topic: Laws of Thermodynamics

This question tests your understanding of the fundamental principles that govern energy transformations in biological systems.

Key Terms and Concepts:

• First Law of Thermodynamics (Law of Conservation of Energy)

• Second Law of Thermodynamics (Law of Entropy)

Step-by-Step Guidance

1. Recall that the first law states that energy cannot be created or destroyed, only transformed from one form to another.

2. The second law states that every energy transfer increases the entropy (disorder) of the universe.

3. Think about how these laws apply to living organisms and their metabolic processes.

Try explaining these laws in your own words before checking the answer!

Q2. What does the law of conservation of energy mean? How would you explain this law (rule)?

Background

Topic: Conservation of Energy

This question focuses on your ability to interpret and explain the first law of thermodynamics in your own words.

Key Terms:

• Energy transformation

• Closed system

Step-by-Step Guidance

1. Start by defining the law of conservation of energy.

2. Consider how energy changes form (e.g., chemical to heat) but the total amount remains constant.

3. Think of examples in biological systems, such as cellular respiration or photosynthesis.

Try to write your own explanation before revealing the answer!

Q3. Be able to explain metabolic reactions. Where do most of these reactions occur in living organisms?

Background

Topic: Metabolism

This question tests your understanding of metabolic pathways and their cellular locations.

Key Terms:

• Metabolism

• Catabolic and anabolic pathways

• Cytoplasm, mitochondria, chloroplasts

Step-by-Step Guidance

1. Define metabolism as the sum of all chemical reactions in a cell.

2. Distinguish between catabolic (breaking down molecules) and anabolic (building molecules) reactions.

3. Identify the main cellular locations where these reactions occur (e.g., cytoplasm, mitochondria, chloroplasts).

Try to list examples of metabolic reactions and their locations before checking the answer!

Q4. Is energy a requirement for living things? Why do living things require energy? What is the difference between anabolic and catabolic reactions?

Background

Topic: Energy in Living Systems

This question explores why organisms need energy and the distinction between two types of metabolic reactions.

Key Terms:

• Anabolic reactions (biosynthesis)

• Catabolic reactions (degradation)

• Energy requirement

Step-by-Step Guidance

1. Explain why energy is essential for cellular processes (e.g., growth, repair, movement).

2. Define anabolic reactions as those that build complex molecules from simpler ones, usually requiring energy input.

3. Define catabolic reactions as those that break down complex molecules into simpler ones, releasing energy.

4. Think of examples for each type of reaction (e.g., protein synthesis vs. glucose breakdown).

Try to answer before revealing the explanation!

Q5. Be able to relate anabolic and catabolic reactions and their roles in energy use.

Background

Topic: Metabolic Pathways and Energy Flow

This question asks you to connect how anabolic and catabolic reactions interact in the cell's energy economy.

Key Terms:

• ATP (adenosine triphosphate)

• Energy coupling

Step-by-Step Guidance

1. Recall that catabolic reactions release energy, often captured in ATP.

2. Understand that anabolic reactions use this ATP to build complex molecules.

3. Think about how these processes are interconnected in cellular metabolism.

Try to explain the relationship before checking the answer!

Q6. Understand the following terms: Substrate, Enzyme, Inhibitor, Oxidation, Reduction, Electron transport system (chain), Active site, Entropy, Reactants, Products, Energy of activation

Background

Topic: Enzymes and Metabolic Reactions

This question requires you to define and understand key terms related to enzyme function and metabolic pathways.

Key Terms:

• Substrate: The molecule upon which an enzyme acts.

• Enzyme: A biological catalyst that speeds up chemical reactions.

• Inhibitor: A substance that decreases enzyme activity.

• Oxidation: Loss of electrons.

• Reduction: Gain of electrons.

• Electron transport chain: Series of proteins that transfer electrons to generate ATP.

• Active site: Region on the enzyme where the substrate binds.

• Entropy: Measure of disorder.

• Reactants: Starting materials in a reaction.

• Products: Substances formed from a reaction.

• Energy of activation: Energy required to start a reaction.

Step-by-Step Guidance

1. Write a brief definition for each term.

2. Try to use each term in a sentence related to metabolism or enzyme function.

Try defining these terms before checking the answer!

Q7. Describe the role of enzymes in biological reactions

Background

Topic: Enzyme Function

This question tests your understanding of how enzymes facilitate biochemical reactions.

Key Terms:

• Catalyst

• Activation energy

• Specificity

Step-by-Step Guidance

1. Recall that enzymes lower the activation energy required for reactions.

2. Explain how enzymes increase the rate of reactions without being consumed.

3. Consider the specificity of enzymes for their substrates.

Try to describe the role of enzymes before checking the answer!

Q8. Define and distinguish between an endergonic and exergonic (biochemical) reaction and be able to give examples. Do the rules of energy (laws of thermodynamics) apply to these reactions?

Background

Topic: Energy in Chemical Reactions

This question asks you to differentiate between reactions that absorb energy and those that release energy, and relate them to thermodynamic laws.

Key Terms and Formulas:

• Endergonic reaction: Absorbs energy ($\Delta G > 0$)

• Exergonic reaction: Releases energy ($\Delta G < 0$)

• Gibbs free energy ($\Delta G$)

Step-by-Step Guidance

1. Define endergonic and exergonic reactions in terms of energy change and $\Delta G$.

2. Think of biological examples (e.g., photosynthesis is endergonic, cellular respiration is exergonic).

3. Explain how the laws of thermodynamics apply to these reactions.

Try to distinguish these reactions before checking the answer!

Q9. What are coupled reactions?

Background

Topic: Energy Coupling in Metabolism

This question tests your understanding of how cells link energy-releasing and energy-consuming reactions.

Key Terms:

• ATP hydrolysis

• Energy transfer

Step-by-Step Guidance

1. Define coupled reactions as the pairing of exergonic and endergonic reactions.

2. Explain how the energy released from one reaction (e.g., ATP hydrolysis) drives another reaction.

3. Think of an example in cellular metabolism.

Try to explain coupled reactions before checking the answer!

Q10. Describe the interactions between enzyme, substrate, active site and the induced fit model

Background

Topic: Enzyme-Substrate Interaction

This question focuses on how enzymes bind substrates and catalyze reactions.

Key Terms:

• Active site

• Induced fit model

• Substrate specificity

Step-by-Step Guidance

1. Describe how the substrate binds to the enzyme's active site.

2. Explain the induced fit model, where the enzyme changes shape to better fit the substrate.

3. Discuss how this interaction lowers activation energy and increases reaction rate.

Try to describe these interactions before checking the answer!

Q11. Explain how changes in temperature and pH affect the function of enzymes

Background

Topic: Enzyme Activity Regulation

This question tests your understanding of how environmental factors influence enzyme function.

Key Terms:

• Denaturation

• Optimal temperature and pH

Step-by-Step Guidance

1. Recall that each enzyme has an optimal temperature and pH for activity.

2. Explain how deviations from these conditions can reduce enzyme activity or denature the enzyme.

3. Think of examples (e.g., human enzymes vs. bacterial enzymes).

Try to explain these effects before checking the answer!

Q12. Recognize the structure of ATP, and be able to identify some key functions of ATP. How is ATP broken down to release energy? How does this relate to anabolic reactions? Catabolic reactions? What about endergonic and exergonic?

Background

Topic: ATP Structure and Function

This question covers the structure of ATP, its role as an energy carrier, and its involvement in metabolic reactions.

Key Terms and Formulas:

• ATP (adenosine triphosphate)

• ATP hydrolysis: $\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$

• Energy coupling

Step-by-Step Guidance

1. Draw or visualize the structure of ATP (adenine, ribose, three phosphate groups).

2. Explain how breaking the terminal phosphate bond releases energy.

3. Relate ATP hydrolysis to exergonic reactions and ATP synthesis to endergonic reactions.

4. Connect ATP use to anabolic and catabolic pathways.

Try to answer these points before checking the answer!

Q13. What is the ATP/ADP cycle? Why is this cycle important, how does it relate to the laws of energy?

Background

Topic: ATP/ADP Cycle

This question focuses on the continuous conversion between ATP and ADP and its significance in cellular energy management.

Key Terms and Formulas:

• ATP synthesis and hydrolysis

• Energy transfer

Step-by-Step Guidance

1. Describe how ATP is formed from ADP and inorganic phosphate using energy from catabolic reactions.

2. Explain how ATP is broken down to ADP to provide energy for cellular work.

3. Relate this cycle to the first and second laws of thermodynamics.

Try to explain the ATP/ADP cycle before checking the answer!

Q14. Does photosynthesis require energy? What type of energy reaction would photosynthesis be? Is photosynthesis an example of a coupled reaction?

Background

Topic: Photosynthesis and Energy

This question tests your understanding of the energy requirements and reaction types involved in photosynthesis.

Key Terms:

• Endergonic reaction

• Energy coupling

Step-by-Step Guidance

1. Recall that photosynthesis requires energy input (light energy).

2. Classify photosynthesis as an endergonic reaction.

3. Consider whether photosynthesis involves coupled reactions (e.g., light and dark reactions).

Try to answer these questions before checking the answer!

Q15. Recognize the (basic) chemical equation for photosynthesis

Background

Topic: Photosynthesis Equation

This question asks you to recall the overall chemical equation for photosynthesis.

Key Formula:

$6\mathrm{CO}_2 + 6\mathrm{H}_2\mathrm{O} + \text{light energy} \rightarrow \mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2$

Step-by-Step Guidance

1. Write out the reactants and products of photosynthesis.

2. Balance the equation to ensure the number of atoms is equal on both sides.

Try to write the equation before checking the answer!

Q16. Describe the structure of a chloroplast and be able to identify parts of the chloroplast as they relate to photosynthesis. Where do the light dependent reactions occur? The light independent (dark) reactions occur?

Background

Topic: Chloroplast Structure and Function

This question tests your knowledge of chloroplast anatomy and the locations of photosynthetic reactions.

Key Terms:

• Thylakoid membrane

• Stroma

• Grana

Step-by-Step Guidance

1. Draw or visualize the main parts of a chloroplast (outer membrane, inner membrane, thylakoids, grana, stroma).

2. Identify where the light-dependent reactions occur (thylakoid membranes).

3. Identify where the light-independent (Calvin cycle) reactions occur (stroma).

Try to label the parts and their functions before checking the answer!

Q17. Describe the function of each of the following in photosynthesis: H2O, Hydrogen ions, Electrons, CO2, Sunlight, O2, Chlorophyll (a, b, carotenoids), NADP, NADPH, Glucose, Electron transport system (chain)

Background

Topic: Photosynthesis Components

This question asks you to explain the role of various molecules and structures in the process of photosynthesis.

Key Terms:

• Electron donor and acceptor

• Energy carriers

• Pigments

Step-by-Step Guidance

1. List each component and briefly describe its role in the light-dependent or light-independent reactions.

2. Connect each component to the overall flow of energy and electrons in photosynthesis.

Try to match each component to its function before checking the answer!

Q18. Describe the light dependent reactions indicating the reactants and products involved. Describe the light independent reactions indicating the reactants and products involved

Background

Topic: Photosynthesis Reactions

This question tests your understanding of the two main stages of photosynthesis and their inputs/outputs.

Key Terms:

• Light-dependent reactions

• Light-independent reactions (Calvin cycle)

• Reactants and products

Step-by-Step Guidance

1. List the main reactants and products of the light-dependent reactions (e.g., H2O, NADP+, ADP, sunlight → O2, NADPH, ATP).

2. List the main reactants and products of the light-independent reactions (e.g., CO2, NADPH, ATP → glucose, NADP+, ADP).

3. Explain how the products of the light-dependent reactions are used in the Calvin cycle.

Try to write out the reactants and products before checking the answer!

Q19. Be able to compare and contrast the light dependent and independent reactions of photosynthesis

Background

Topic: Photosynthesis Pathways

This question asks you to identify similarities and differences between the two stages of photosynthesis.

Key Terms:

• Location

• Inputs and outputs

• Energy transformations

Step-by-Step Guidance

1. List the location, reactants, and products for each stage.

2. Compare the energy sources and the types of molecules produced.

3. Contrast the dependence on light for each stage.

Try to make a comparison table before checking the answer!

Q20. Is photosynthesis only occurring during the daytime? What happens when there is no light? What is the relationship between light dependent and light independent reactions in photosynthesis?

Background

Topic: Regulation of Photosynthesis

This question explores when photosynthesis occurs and how the two stages are connected.

Key Terms:

• Light-dependent reactions

• Calvin cycle

• Energy carriers (ATP, NADPH)

Step-by-Step Guidance

1. Explain that light-dependent reactions require light and occur during the day.

2. Describe how the Calvin cycle can continue as long as ATP and NADPH are available.

3. Discuss the interdependence of the two stages.

Try to answer these questions before checking the answer!

Q21. Be able to relate how changes in carbon dioxide concentration, temperature, light intensity, light color has on the rate(s) of photosynthesis.

Background

Topic: Factors Affecting Photosynthesis

This question tests your understanding of how environmental factors influence the rate of photosynthesis.

Key Terms:

• Limiting factors

• Photosynthetic rate

Step-by-Step Guidance

1. Consider how increasing CO2 concentration affects the rate up to a certain point.

2. Explain the effect of temperature on enzyme activity in photosynthesis.

3. Discuss how light intensity and color influence the rate of photosynthesis.

Try to predict the effects before checking the answer!

Q22. Recognize the overall chemical equation for cellular respiration

Background

Topic: Cellular Respiration Equation

This question asks you to recall the overall equation for aerobic cellular respiration.

Key Formula:

$\mathrm{C}_6\mathrm{H}_{12}\mathrm{O}_6 + 6\mathrm{O}_2 \rightarrow 6\mathrm{CO}_2 + 6\mathrm{H}_2\mathrm{O} + \text{energy (ATP)}$

Step-by-Step Guidance

1. Write out the reactants and products of cellular respiration.

2. Balance the equation to ensure the number of atoms is equal on both sides.

Try to write the equation before checking the answer!

Q23. What are the reactants involved, what are the products that are formed? How is cellular respiration different or similar to photosynthesis?

Background

Topic: Comparing Photosynthesis and Respiration

This question asks you to compare the inputs and outputs of cellular respiration and photosynthesis.

Key Terms:

• Reactants and products

• Energy flow

Step-by-Step Guidance

1. List the reactants and products for both processes.

2. Compare the direction of energy flow (energy storage vs. energy release).

3. Note the complementary nature of the two processes.

Try to compare the two processes before checking the answer!

Q24. Be able to explain the differences between aerobic cellular respiration, anaerobic cellular respiration and fermentation

Background

Topic: Types of Cellular Respiration

This question tests your understanding of the different pathways cells use to generate energy.

Key Terms:

• Aerobic respiration

• Anaerobic respiration

• Fermentation

Step-by-Step Guidance

1. Define aerobic respiration as requiring oxygen and producing the most ATP.

2. Define anaerobic respiration as occurring without oxygen, using other electron acceptors.

3. Define fermentation as an anaerobic process that produces less ATP and different end products.

4. Compare the efficiency and products of each pathway.

Try to explain the differences before checking the answer!

Q25. Know the major steps in aerobic cellular respiration

Background

Topic: Aerobic Respiration Pathway

This question asks you to identify the main stages of aerobic cellular respiration.

Key Terms:

• Glycolysis

• Krebs cycle (Citric acid cycle)

• Electron transport chain

Step-by-Step Guidance

1. List the three main stages of aerobic respiration.

2. Briefly describe what happens in each stage (e.g., location, main products).

Try to outline the steps before checking the answer!

Q26. What are the intermediate (end) products of each step in the cellular respiration pathway? Be able to describe the mitochondrion and where in the mitochondrion steps of cellular respiration take place

Background

Topic: Cellular Respiration Steps and Mitochondrial Structure

This question tests your knowledge of the products of each stage and the locations within the mitochondrion.

Key Terms:

• Pyruvate

• NADH, FADH2

• ATP

• Mitochondrial matrix, inner membrane

Step-by-Step Guidance

1. List the main products of glycolysis, Krebs cycle, and electron transport chain.

2. Identify where each step occurs within the mitochondrion.

Try to match products and locations before checking the answer!

Q27. Recognize in which step of cellular respiration generates the most ATP molecules. Which process in the cellular respiration pathway does not generate ATP?

Background

Topic: ATP Yield in Respiration

This question asks you to identify which stage produces the most ATP and which does not produce ATP directly.

Key Terms:

• Electron transport chain

• Krebs cycle

• Glycolysis

Step-by-Step Guidance

1. Recall the ATP yield from each stage of cellular respiration.

2. Identify which stage produces the most ATP (hint: involves oxidative phosphorylation).

3. Determine which step does not directly generate ATP.

Try to answer before checking the answer!

Q28. Describe the functions of each of the following in cellular respiration: Glucose, O2, NAD, CO2, FAD, ADP, Chemiosmosis, ATP, electron transport system (chain), oxidative phosphorylation, Electrons, H ion gradients

Background

Topic: Cellular Respiration Components

This question asks you to explain the role of various molecules and processes in cellular respiration.

Key Terms:

• Electron carriers

• ATP synthesis

• Proton gradient

Step-by-Step Guidance

1. List each component and briefly describe its role in the process of cellular respiration.

2. Connect each component to the overall flow of energy and electrons in respiration.

Try to match each component to its function before checking the answer!