BIO 1150 Exam 2 Study Guide – Step-by-Step Guidance

Q1. What components are shared between prokaryotic and eukaryotic cells?

Background

Topic: Cell Structure and Function

This question tests your understanding of the basic similarities between the two major cell types: prokaryotic and eukaryotic cells.

Key Terms:

• Prokaryotic cells: Cells without a nucleus or membrane-bound organelles.

• Eukaryotic cells: Cells with a nucleus and membrane-bound organelles.

Step-by-Step Guidance

1. Recall the basic structures that all cells must have to function and survive.

2. Think about the essential processes of life (e.g., genetic information storage, protein synthesis, boundary formation, and metabolism).

3. List the cellular components that are present in both prokaryotic and eukaryotic cells, focusing on those required for the above processes.

4. Consider which structures are unique to eukaryotes (e.g., nucleus, mitochondria) and exclude those from your list.

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Q2. What are the limiting factors on cell size, both on the small and large ends of the spectrum?

Background

Topic: Cell Size and Surface Area-to-Volume Ratio

This question examines your understanding of why cells are limited in how small or large they can be, based on structural and functional constraints.

Key Concepts:

• Surface area-to-volume ratio: The relationship between the surface area of a cell and its volume, which affects the efficiency of material exchange.

• Minimum requirements: The smallest size a cell can be and still contain all necessary components for life.

Step-by-Step Guidance

1. Think about what a cell must contain to survive (e.g., DNA, ribosomes, cytoplasm).

2. Consider why a cell cannot be too small—what would be missing if it were?

3. Now, consider why a cell cannot be too large—how does the surface area-to-volume ratio affect nutrient and waste exchange?

4. Relate these ideas to the efficiency of diffusion and the cell's ability to support its metabolic needs.

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Q3. What are the advantages of having organelles within a cell?

Background

Topic: Cell Compartmentalization and Organelle Function

This question tests your understanding of why eukaryotic cells have membrane-bound organelles and how this benefits cellular function.

Key Terms:

• Organelle: Specialized structure within a cell that performs a specific function.

• Compartmentalization: The division of the cell into distinct regions, each with unique functions.

Step-by-Step Guidance

1. Recall the main functions of organelles (e.g., energy production, protein synthesis, waste processing).

2. Think about how separating these functions into different compartments could increase efficiency.

3. Consider how compartmentalization can prevent interference between incompatible chemical reactions.

4. Reflect on how organelles allow for specialization and regulation within the cell.

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Q4. Describe the flow of material through the endomembrane system. For example, how would a protein that is secreted from the cell move through the different organelles and eventually be released into the extracellular fluid?

Background

Topic: Endomembrane System and Protein Trafficking

This question tests your understanding of how proteins are synthesized, processed, and transported within eukaryotic cells.

Key Terms:

• Endomembrane system: A group of membranes and organelles in eukaryotic cells that work together to modify, package, and transport lipids and proteins.

• Rough ER, Golgi apparatus, vesicles, plasma membrane: Key components involved in protein secretion.

Step-by-Step Guidance

1. Start with the synthesis of the protein—where does this occur and what information is needed?

2. Describe how the protein enters the endomembrane system (e.g., rough ER).

3. Explain how the protein is modified and sorted in the Golgi apparatus.

4. Discuss how the protein is packaged into vesicles and transported to the plasma membrane for secretion.

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Q5. What evidence supports the endosymbiosis theory?

Background

Topic: Evolution of Eukaryotic Cells

This question tests your understanding of the evidence that mitochondria and chloroplasts originated from prokaryotic ancestors.

Key Terms:

• Endosymbiosis theory: The idea that certain organelles originated as free-living bacteria that were engulfed by ancestral eukaryotic cells.

• Mitochondria, chloroplasts: Organelles believed to have prokaryotic origins.

Step-by-Step Guidance

1. Recall the structural and genetic similarities between mitochondria/chloroplasts and prokaryotes.

2. Think about the type of DNA found in these organelles and how it compares to nuclear DNA.

3. Consider the characteristics of ribosomes in mitochondria and chloroplasts.

4. Reflect on how these organelles replicate and whether this process is independent of the host cell's division.

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Q6. How does an enzyme increase the rate of a reaction?

Background

Topic: Enzyme Function and Catalysis

This question tests your understanding of how enzymes act as biological catalysts to speed up chemical reactions.

Key Terms and Concepts:

• Enzyme: A protein that speeds up chemical reactions by lowering activation energy.

• Activation energy: The energy required to start a reaction.

• Active site: The region of the enzyme where the substrate binds.

Step-by-Step Guidance

1. Recall what activation energy is and why it matters for chemical reactions.

2. Think about how enzymes interact with substrates at the active site.

3. List the ways enzymes can lower activation energy (e.g., bond stretching, providing optimal conditions, orienting substrates).

4. Consider how these mechanisms increase the rate of product formation.

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Q7. Why do you think the cell is shuttling the mutated Protein A to the lysosomes instead of secreting it?

Background

Topic: Protein Sorting and Quality Control

This question tests your understanding of how cells recognize and handle defective or misfolded proteins.

Key Terms:

• Lysosome: Organelle responsible for breaking down waste and defective cellular components.

• Protein quality control: Cellular mechanisms that detect and degrade abnormal proteins.

Step-by-Step Guidance

1. Recall the normal pathway for protein secretion (rough ER → Golgi → plasma membrane).

2. Think about what happens when a protein is mutated or misfolded—how does the cell detect this?

3. Consider the role of lysosomes in degrading and recycling defective proteins.

4. Reflect on why it is beneficial for the cell to remove mutated proteins rather than secrete them.

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Q8. What forces maintain the structure of membranes?

Background

Topic: Membrane Structure and Stability

This question tests your understanding of the molecular interactions that stabilize biological membranes.

Key Terms:

• Phospholipid bilayer: The fundamental structure of cell membranes.

• Hydrophilic and hydrophobic interactions: Forces that drive the arrangement of membrane components.

• Hydrogen bonds, Van der Waals interactions: Types of molecular forces involved.

Step-by-Step Guidance

1. Recall the structure of a phospholipid and how these molecules arrange themselves in water.

2. Think about the interactions between hydrophilic heads and the aqueous environment inside and outside the cell.

3. Consider the interactions between hydrophobic tails within the membrane interior.

4. Reflect on the role of proteins and the cytoskeleton in supporting membrane structure.

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Q9. Why does cholera infection cause massive fluid loss through diarrhea? Use the terms hypertonic or hypotonic in your explanation.

Background

Topic: Osmosis and Membrane Transport

This question tests your understanding of how solute concentration differences drive water movement across cell membranes.

Key Terms:

• Osmosis: The movement of water across a semipermeable membrane from low to high solute concentration.

• Hypertonic: A solution with a higher solute concentration compared to another solution.

• Hypotonic: A solution with a lower solute concentration compared to another solution.

Step-by-Step Guidance

1. Recall what happens when chloride and sodium ions are secreted into the intestinal fluid—how does this affect the tonicity of the fluid?

2. Think about the direction water will move via osmosis when the intestinal fluid becomes hypertonic compared to the cells lining the intestine.

3. Explain how this water movement leads to fluid loss from the body.

4. Relate this process to the symptoms of cholera (severe diarrhea and dehydration).

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