Skip to main content
Indietro

Comprehensive Study Guide for General Biology: Cellular Respiration, Photosynthesis, and Cell Division

NotePraticaVideolezioni

Guida di studio - Note intelligenti

Appunti personalizzati basati sui tuoi materiali, ampliati con definizioni chiave, esempi e contesto.

Q1. What are oxidation and reduction reactions? What is oxidized, what is reduced, and what are oxidizing/reducing agents?

Background

Topic: Redox Reactions in Biology

This question tests your understanding of how electrons are transferred in biological systems, and how to identify what is being oxidized or reduced in a reaction.

Key Terms:

  • Oxidation: Loss of electrons

  • Reduction: Gain of electrons

  • Oxidizing agent: Substance that gains electrons (is reduced)

  • Reducing agent: Substance that loses electrons (is oxidized)

Step-by-Step Guidance

  1. Recall that oxidation is the loss of electrons, while reduction is the gain of electrons.

  2. In a redox reaction, identify which molecule or atom loses electrons (oxidized) and which gains electrons (reduced).

  3. Determine which substance acts as the oxidizing agent (accepts electrons) and which acts as the reducing agent (donates electrons).

  4. Write a sample equation, such as , and identify the changes in electron states.

Try solving on your own before revealing the answer!

Final Answer:

Oxidation is the loss of electrons; reduction is the gain of electrons. The substance that is oxidized loses electrons and is the reducing agent. The substance that is reduced gains electrons and is the oxidizing agent. For example, in the reaction , is oxidized and is reduced.

Q2. What is the function of NAD+ and NADP+, and how are they regenerated?

Background

Topic: Electron Carriers in Metabolism

This question tests your knowledge of the roles of NAD+ and NADP+ in cellular respiration and photosynthesis, and how these molecules cycle between oxidized and reduced forms.

Key Terms:

  • NAD+: Nicotinamide adenine dinucleotide (oxidized form)

  • NADH: Reduced form of NAD+

  • NADP+: Phosphorylated NAD+ (used in photosynthesis)

  • NADPH: Reduced form of NADP+

Step-by-Step Guidance

  1. Recall that NAD+ and NADP+ are electron carriers that accept electrons during metabolic reactions.

  2. Understand that NAD+ is reduced to NADH during glycolysis and the Krebs cycle, while NADP+ is reduced to NADPH during the light reactions of photosynthesis.

  3. Regeneration occurs when NADH and NADPH donate electrons to other molecules, returning to their oxidized forms.

  4. Consider where in the cell these regeneration steps occur (e.g., electron transport chain for NADH).

Try solving on your own before revealing the answer!

Final Answer:

NAD+ and NADP+ function as electron carriers, accepting electrons and becoming NADH and NADPH, respectively. They are regenerated when NADH and NADPH donate electrons to the electron transport chain (respiration) or Calvin cycle (photosynthesis), returning to their oxidized forms.

Q3. What are the phases of respiration: Glycolysis, pyruvate oxidation & Krebs cycle, and oxidative phosphorylation? Explain all three phases in detail, including reactants, products, and energy output.

Background

Topic: Cellular Respiration

This question tests your ability to describe the steps of cellular respiration, including the inputs and outputs of each phase.

Key Terms and Formulas:

  • Glycolysis: Breakdown of glucose to pyruvate

  • Pyruvate oxidation: Conversion of pyruvate to acetyl-CoA

  • Krebs cycle: Series of reactions generating NADH, FADH2, and ATP

  • Oxidative phosphorylation: ATP production via electron transport chain and chemiosmosis

Step-by-Step Guidance

  1. Start with glycolysis: Identify the reactant (glucose) and the products (pyruvate, ATP, NADH).

  2. Describe pyruvate oxidation: Pyruvate is converted to acetyl-CoA, producing NADH and CO2.

  3. Explain the Krebs cycle: Acetyl-CoA enters the cycle, generating NADH, FADH2, ATP, and CO2.

  4. Outline oxidative phosphorylation: NADH and FADH2 donate electrons to the electron transport chain, leading to ATP synthesis.

  5. Summarize the energy output (ATP, NADH, FADH2) for each phase, but stop before calculating the total ATP yield.

Try solving on your own before revealing the answer!

Final Answer:

Glycolysis produces 2 ATP, 2 NADH, and 2 pyruvate per glucose. Pyruvate oxidation yields 2 NADH and 2 acetyl-CoA. The Krebs cycle generates 2 ATP, 6 NADH, 2 FADH2, and 4 CO2 per glucose. Oxidative phosphorylation uses NADH and FADH2 to produce about 28–32 ATP via the electron transport chain and chemiosmosis.

Q4. What is substrate-level phosphorylation and how is it different from oxidative phosphorylation? In which phase of respiration do they occur?

Background

Topic: ATP Formation Mechanisms

This question tests your understanding of how ATP is generated during cellular respiration and the differences between the two main mechanisms.

Key Terms:

  • Substrate-level phosphorylation: Direct transfer of a phosphate group to ADP from a substrate

  • Oxidative phosphorylation: ATP synthesis powered by the electron transport chain and proton gradient

Step-by-Step Guidance

  1. Define substrate-level phosphorylation and identify where it occurs (glycolysis and Krebs cycle).

  2. Define oxidative phosphorylation and explain its reliance on the electron transport chain and chemiosmosis.

  3. Compare the two processes in terms of mechanism and location within the cell.

  4. List which phases of respiration use each type of phosphorylation.

Try solving on your own before revealing the answer!

Final Answer:

Substrate-level phosphorylation occurs in glycolysis and the Krebs cycle, directly transferring a phosphate to ADP. Oxidative phosphorylation occurs in the mitochondria, using the electron transport chain and proton gradient to synthesize ATP. The main difference is that substrate-level phosphorylation does not require oxygen or the electron transport chain.

Q5. What is the role of oxygen in respiration?

Background

Topic: Aerobic Respiration

This question tests your understanding of why oxygen is essential for cellular respiration.

Key Terms:

  • Final electron acceptor

  • Electron transport chain

  • ATP production

Step-by-Step Guidance

  1. Recall that oxygen is the final electron acceptor in the electron transport chain.

  2. Explain how oxygen allows NADH and FADH2 to donate electrons, regenerating NAD+ and FAD.

  3. Describe what happens if oxygen is not present (e.g., fermentation).

  4. Discuss the importance of oxygen for efficient ATP production.

Try solving on your own before revealing the answer!

Final Answer:

Oxygen acts as the final electron acceptor in the electron transport chain, allowing electrons to combine with protons to form water. This process is essential for regenerating NAD+ and FAD, enabling continued ATP production via oxidative phosphorylation.

Q6. What are the equations for respiration and photosynthesis?

Background

Topic: Metabolic Pathways

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

Key Formulas:

  • Cellular Respiration:

  • Photosynthesis:

Step-by-Step Guidance

  1. Recall the reactants and products for each process.

  2. Write the balanced equation for cellular respiration.

  3. Write the balanced equation for photosynthesis.

  4. Compare the two equations to see how they are essentially reverse processes.

Try solving on your own before revealing the answer!

Final Answer:

Cellular Respiration: Photosynthesis:

Q7. How do anaerobic and aerobic respiration differ in terms of final electron acceptors?

Background

Topic: Types of Respiration

This question tests your understanding of the differences between aerobic and anaerobic respiration, especially regarding the molecules that accept electrons at the end of the electron transport chain.

Key Terms:

  • Aerobic respiration: Oxygen is the final electron acceptor

  • Anaerobic respiration: Other molecules (e.g., sulfate, nitrate) are final electron acceptors

Step-by-Step Guidance

  1. Recall that aerobic respiration uses oxygen as the final electron acceptor.

  2. Identify alternative electron acceptors used in anaerobic respiration (e.g., nitrate, sulfate).

  3. Explain how the choice of electron acceptor affects ATP yield and byproducts.

  4. Consider examples of organisms that use each type of respiration.

Try solving on your own before revealing the answer!

Final Answer:

In aerobic respiration, oxygen is the final electron acceptor. In anaerobic respiration, other molecules such as nitrate (), sulfate (), or carbon dioxide () serve as final electron acceptors, resulting in different byproducts and less ATP.

Q8. Trace the gradual decline of carbons from glucose to acetyl-CoA. Start with glucose (6 carbons) and explain how they gradually decline.

Background

Topic: Carbon Tracking in Cellular Respiration

This question tests your ability to follow the fate of carbon atoms as glucose is broken down during cellular respiration.

Key Terms:

  • Glucose: 6-carbon molecule

  • Pyruvate: 3-carbon molecule

  • Acetyl-CoA: 2-carbon molecule

  • CO2: Carbon dioxide (released)

Step-by-Step Guidance

  1. Start with glucose (), which has 6 carbons.

  2. During glycolysis, glucose is split into two pyruvate molecules, each with 3 carbons.

  3. During pyruvate oxidation, each pyruvate loses one carbon as CO2, forming acetyl-CoA (2 carbons).

  4. Track the fate of the remaining carbons as they enter the Krebs cycle.

Try solving on your own before revealing the answer!

Final Answer:

Glucose (6 carbons) is split into two pyruvate molecules (3 carbons each). Each pyruvate loses one carbon as CO2 during pyruvate oxidation, resulting in two acetyl-CoA molecules (2 carbons each). The remaining carbons are eventually released as CO2 in the Krebs cycle.

Q9. How does the electron transport chain (ETC) generate ATP? Understand how the ETC generates a proton gradient and how that proton gradient eventually generates ATP.

Background

Topic: Chemiosmosis and ATP Synthesis

This question tests your understanding of the mechanism by which the ETC creates a proton gradient and how this gradient drives ATP synthesis.

Key Terms:

  • Electron transport chain (ETC)

  • Proton gradient

  • ATP synthase

  • Chemiosmosis

Step-by-Step Guidance

  1. Recall that NADH and FADH2 donate electrons to the ETC.

  2. As electrons move through the ETC, energy is used to pump protons (H+) across the inner mitochondrial membrane.

  3. This creates a proton gradient (higher concentration outside the matrix).

  4. Protons flow back through ATP synthase, driving the synthesis of ATP from ADP and inorganic phosphate.

Try solving on your own before revealing the answer!

Final Answer:

The ETC uses energy from electron transfer to pump protons across the inner mitochondrial membrane, creating a proton gradient. ATP synthase allows protons to flow back into the matrix, using this energy to convert ADP and inorganic phosphate into ATP (chemiosmosis).

Q10. What is fermentation? What are the reactants, products, and final electron acceptors in both types of fermentation?

Background

Topic: Anaerobic Metabolism

This question tests your understanding of fermentation, including the differences between lactic acid and alcoholic fermentation.

Key Terms:

  • Fermentation: Anaerobic process to regenerate NAD+

  • Lactic acid fermentation

  • Alcoholic fermentation

  • Final electron acceptor

Step-by-Step Guidance

  1. Recall that fermentation occurs when oxygen is absent.

  2. Identify the reactants (pyruvate, NADH) and products (lactic acid or ethanol, CO2, NAD+).

  3. Describe the final electron acceptor in each type: pyruvate (lactic acid) or acetaldehyde (alcoholic).

  4. Compare the two types of fermentation in terms of products and organisms.

Try solving on your own before revealing the answer!

Final Answer:

Fermentation is an anaerobic process that regenerates NAD+. In lactic acid fermentation, pyruvate is the final electron acceptor and is converted to lactic acid. In alcoholic fermentation, acetaldehyde is the final electron acceptor, producing ethanol and CO2. Both processes use pyruvate and NADH as reactants.

Q11. During respiration, where does the energy needed to make ATP come from?

Background

Topic: Energy Transfer in Respiration

This question tests your understanding of how energy is released and transferred during cellular respiration.

Key Terms:

  • Glucose

  • Electron carriers (NADH, FADH2)

  • Proton gradient

  • ATP synthase

Step-by-Step Guidance

  1. Recall that energy is stored in the chemical bonds of glucose.

  2. During glycolysis and the Krebs cycle, electrons are transferred to NAD+ and FAD, forming NADH and FADH2.

  3. NADH and FADH2 donate electrons to the ETC, releasing energy to pump protons.

  4. The proton gradient provides the energy for ATP synthase to make ATP.

Try solving on your own before revealing the answer!

Final Answer:

The energy to make ATP comes from the chemical bonds in glucose, transferred to electron carriers (NADH, FADH2), and then released as electrons move through the electron transport chain, creating a proton gradient that powers ATP synthase.

Q12. What are the reactants and products of the light reactions and Calvin cycle, and where does each phase take place?

Background

Topic: Photosynthesis

This question tests your understanding of the two main stages of photosynthesis and their locations within the chloroplast.

Key Terms:

  • Light reactions: Occur in thylakoid membranes

  • Calvin cycle: Occurs in stroma

  • Reactants and products for each phase

Step-by-Step Guidance

  1. Identify the reactants for the light reactions (water, light, NADP+, ADP).

  2. List the products of the light reactions (oxygen, NADPH, ATP).

  3. Identify the reactants for the Calvin cycle (CO2, NADPH, ATP).

  4. List the products of the Calvin cycle (glucose, NADP+, ADP).

  5. State the location of each phase within the chloroplast.

Try solving on your own before revealing the answer!

Final Answer:

Light reactions occur in the thylakoid membranes and produce oxygen, NADPH, and ATP from water and light. The Calvin cycle occurs in the stroma and uses CO2, NADPH, and ATP to produce glucose, NADP+, and ADP.

Q13. What is the structure and function of Photosystem II and Photosystem I?

Background

Topic: Light Reactions in Photosynthesis

This question tests your understanding of the roles and differences between Photosystem II and Photosystem I in the light reactions.

Key Terms:

  • Photosystem II (PSII): First photosystem in light reactions

  • Photosystem I (PSI): Second photosystem

  • Electron transport

  • ATP and NADPH production

Step-by-Step Guidance

  1. Describe the structure of each photosystem (protein complex with pigments).

  2. Explain the function of PSII (splits water, releases oxygen, initiates electron transport).

  3. Explain the function of PSI (receives electrons, produces NADPH).

  4. Compare their roles in the light reactions.

Try solving on your own before revealing the answer!

Final Answer:

Photosystem II splits water to release oxygen and initiates electron transport, leading to ATP production. Photosystem I receives electrons from PSII and uses them to reduce NADP+ to NADPH. Both are protein complexes with pigment molecules that absorb light energy.

Q14. What is the relationship between the light reactions and the Calvin cycle? Explain how the products of the light reactions are used in the Calvin cycle.

Background

Topic: Integration of Photosynthesis Stages

This question tests your understanding of how the two stages of photosynthesis are connected.

Key Terms:

  • ATP

  • NADPH

  • Calvin cycle

Step-by-Step Guidance

  1. Recall that the light reactions produce ATP and NADPH.

  2. Explain that the Calvin cycle uses ATP and NADPH to fix carbon dioxide into glucose.

  3. Describe how the products of the light reactions are transported to the stroma for use in the Calvin cycle.

  4. Discuss the cyclical nature of NADP+ and ADP regeneration.

Try solving on your own before revealing the answer!

Final Answer:

The light reactions produce ATP and NADPH, which are used by the Calvin cycle to convert CO2 into glucose. The Calvin cycle regenerates NADP+ and ADP, which return to the light reactions for reuse.

Q15. What is the carbon dioxide acceptor in the Calvin cycle and what is the name of the sugar made in the second stage?

Background

Topic: Calvin Cycle Details

This question tests your knowledge of the molecules involved in carbon fixation and sugar production during photosynthesis.

Key Terms:

  • RuBP (ribulose bisphosphate): CO2 acceptor

  • G3P (glyceraldehyde-3-phosphate): Sugar produced

Step-by-Step Guidance

  1. Identify the molecule that binds CO2 in the first step of the Calvin cycle.

  2. Recall the enzyme (Rubisco) that catalyzes this reaction.

  3. Determine the sugar produced in the second stage of the Calvin cycle.

  4. Understand how G3P is used to form glucose and other carbohydrates.

Try solving on your own before revealing the answer!

Final Answer:

RuBP (ribulose bisphosphate) is the carbon dioxide acceptor in the Calvin cycle. G3P (glyceraldehyde-3-phosphate) is the sugar produced in the second stage, which can be used to make glucose and other carbohydrates.

Q16. Explain photorespiration.

Background

Topic: Photosynthetic Efficiency

This question tests your understanding of photorespiration and its impact on plant metabolism.

Key Terms:

  • Photorespiration

  • Rubisco

  • Oxygen fixation

  • Energy loss

Step-by-Step Guidance

  1. Recall that photorespiration occurs when Rubisco binds O2 instead of CO2.

  2. Describe the conditions that favor photorespiration (high O2, low CO2).

  3. Explain the consequences: energy loss and reduced sugar production.

  4. Discuss adaptations in plants to minimize photorespiration.

Try solving on your own before revealing the answer!

Final Answer:

Photorespiration occurs when Rubisco fixes oxygen instead of carbon dioxide, leading to the production of a molecule that must be recycled, resulting in energy loss and reduced sugar output. It is more common in hot, dry conditions.

Q17. Describe the adaptations of C3, C4, and CAM plants to dry climates.

Background

Topic: Plant Adaptations

This question tests your understanding of how different types of plants adapt to minimize water loss and photorespiration.

Key Terms:

  • C3 plants

  • C4 plants

  • CAM plants

  • Adaptations to dry climates

Step-by-Step Guidance

  1. Recall that C3 plants use the Calvin cycle directly and are less efficient in hot, dry climates.

  2. Describe how C4 plants separate carbon fixation and the Calvin cycle spatially to reduce photorespiration.

  3. Explain how CAM plants separate these processes temporally (night vs. day).

  4. Discuss how these adaptations help conserve water and reduce photorespiration.

Try solving on your own before revealing the answer!

Final Answer:

C3 plants are less efficient in dry climates due to photorespiration. C4 plants fix carbon in mesophyll cells and perform the Calvin cycle in bundle sheath cells, reducing photorespiration. CAM plants fix carbon at night and perform the Calvin cycle during the day, conserving water.

Q18. How are autotrophs different from heterotrophs?

Background

Topic: Modes of Nutrition

This question tests your understanding of the differences between organisms that make their own food and those that rely on others.

Key Terms:

  • Autotroph: Makes own food (e.g., plants)

  • Heterotroph: Consumes other organisms for food (e.g., animals)

Step-by-Step Guidance

  1. Define autotroph and heterotroph.

  2. Describe how autotrophs obtain energy (photosynthesis or chemosynthesis).

  3. Explain how heterotrophs obtain energy (consuming organic matter).

  4. Give examples of each type.

Try solving on your own before revealing the answer!

Final Answer:

Autotrophs produce their own food using sunlight or inorganic chemicals, while heterotrophs obtain energy by consuming other organisms. Plants are autotrophs; animals are heterotrophs.

Q19. What are the types of pigments and their role in photosynthesis?

Background

Topic: Pigments in Photosynthesis

This question tests your knowledge of the different pigments involved in capturing light energy for photosynthesis.

Key Terms:

  • Chlorophyll a

  • Chlorophyll b

  • Carotenoids

  • Light absorption

Step-by-Step Guidance

  1. List the main types of pigments (chlorophyll a, chlorophyll b, carotenoids).

  2. Describe the role of each pigment in absorbing light energy.

  3. Explain how pigments expand the range of light wavelengths used in photosynthesis.

  4. Discuss the importance of pigment diversity for plant survival.

Try solving on your own before revealing the answer!

Final Answer:

Chlorophyll a is the primary pigment for photosynthesis, absorbing mainly blue and red light. Chlorophyll b and carotenoids absorb additional wavelengths, broadening the spectrum of light used and protecting against excess light.

Q20. Identify the parts of mitochondria and chloroplast (figures).

Background

Topic: Cell Organelle Structure

This question tests your ability to recognize and label the structural components of mitochondria and chloroplasts.

Key Terms:

  • Mitochondria: Matrix, inner membrane, cristae, intermembrane space

  • Chloroplast: Thylakoid, stroma, grana, inner and outer membranes

Step-by-Step Guidance

  1. Review diagrams of mitochondria and chloroplasts.

  2. Identify and label the main parts of each organelle.

  3. Understand the function of each part (e.g., ATP synthesis in cristae, light reactions in thylakoids).

  4. Compare the structural features of both organelles.

Try solving on your own before revealing the answer!

Final Answer:

Mitochondria: Matrix, inner membrane, cristae, intermembrane space. Chloroplast: Thylakoid, stroma, grana, inner and outer membranes. Each part has a specific function related to energy conversion.

Q21. What are the stages of interphase and mitosis (prophase, metaphase, anaphase, telophase, and cytokinesis), and what happens in each stage? Describe each stage in detail.

Background

Topic: Cell Cycle and Division

This question tests your understanding of the phases of the cell cycle and mitosis, including the events that occur in each stage.

Key Terms:

  • Interphase: G1, S, G2

  • Mitosis: Prophase, metaphase, anaphase, telophase

  • Cytokinesis

Step-by-Step Guidance

  1. Describe the stages of interphase (G1: growth, S: DNA synthesis, G2: preparation for mitosis).

  2. Explain prophase (chromosome condensation, spindle formation).

  3. Describe metaphase (chromosomes align at the metaphase plate).

  4. Explain anaphase (sister chromatids separate).

  5. Describe telophase (nuclear envelope reforms, chromosomes decondense).

  6. Outline cytokinesis (division of cytoplasm).

Try solving on your own before revealing the answer!

Final Answer:

Interphase includes G1 (cell growth), S (DNA replication), and G2 (preparation for mitosis). Mitosis consists of prophase (chromosomes condense), metaphase (chromosomes align), anaphase (chromatids separate), telophase (nuclear envelope reforms), and cytokinesis (cytoplasm divides).

Pearson Logo

Study Prep