BIOL 1406 Unit 2 Study Guide – Cell Structure and Function

Q1. Compare and contrast light microscopes: brightfield (stained and unstained), phase contrast, fluorescence, and confocal. Explain the benefits/applications of each.

Background

Topic: Microscopy Techniques

This question tests your understanding of different types of light microscopy, their principles, and their applications in biology.

Key Terms

• Brightfield Microscopy (stained/unstained)

• Phase Contrast Microscopy

• Fluorescence Microscopy

• Confocal Microscopy

Step-by-Step Guidance

1. Define each type of light microscope and describe how it works (e.g., how light interacts with the sample).

2. Explain the advantages and limitations of each technique (e.g., resolution, contrast, ability to view live cells).

3. Discuss specific applications or examples where each type is most useful.

4. Compare and contrast the techniques, focusing on what makes each unique.

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Q2. Compare and contrast electron microscopes: scanning and transmission. Explain the benefits/applications of each.

Background

Topic: Electron Microscopy

This question focuses on the differences between scanning electron microscopes (SEM) and transmission electron microscopes (TEM), including their uses and advantages.

Key Terms

• Scanning Electron Microscope (SEM)

• Transmission Electron Microscope (TEM)

• Resolution

• Sample Preparation

Step-by-Step Guidance

1. Describe how SEM and TEM work, including the path of electrons and how images are formed.

2. List the main differences in what each microscope can visualize (surface vs. internal structures).

3. Explain the benefits and limitations of each technique.

4. Give examples of biological questions or samples best suited for each type.

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Q3. A biology student was studying bacteria found in the intestines of tigers on different diets. How could she isolate the bacterial ribosomes so she could identify the bacteria by their specific types of ribosomal RNA? Explain clearly.

Background

Topic: Cell Fractionation and Ribosome Isolation

This question tests your understanding of laboratory techniques for separating cellular components, specifically ribosomes, for molecular identification.

Key Terms and Concepts

• Cell Fractionation

• Centrifugation

• Ribosomal RNA (rRNA)

Step-by-Step Guidance

1. Describe the process of cell lysis to break open bacterial cells.

2. Explain how differential centrifugation can be used to separate cellular components by size and density.

3. Identify the centrifugation steps needed to pellet ribosomes.

4. Discuss how the isolated ribosomes can be used to extract rRNA for identification.

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Q4. In the microbe world, big is better. You can’t be eaten by something smaller than you. Why is being multicellular better than just being a bigger cell? Explain the surface area to volume ratio.

Background

Topic: Cell Size and Multicellularity

This question explores the biological significance of surface area to volume ratio and why multicellularity is advantageous over simply increasing cell size.

Key Terms and Formulas

• Surface Area to Volume Ratio (SA:V)

• Diffusion

• Multicellularity

Step-by-Step Guidance

1. Define surface area and volume for a cell (e.g., for a sphere: $SA = 4\pi r^2$, $V = \frac{4}{3}\pi r^3$).

2. Explain how the SA:V ratio changes as a cell increases in size.

3. Discuss why a high SA:V ratio is important for cell function (e.g., nutrient/waste exchange).

4. Describe how multicellularity helps organisms overcome the limitations of low SA:V ratios in large cells.

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Q5. Clearly differentiate between prokaryotic and eukaryotic cells. Clearly differentiate between plant and animal cells.

Background

Topic: Cell Types and Classification

This question tests your ability to distinguish between major cell types and their unique features.

Key Terms

• Prokaryotic Cells

• Eukaryotic Cells

• Plant Cells

• Animal Cells

Step-by-Step Guidance

1. List the defining features of prokaryotic cells (e.g., lack of nucleus, organelles).

2. List the defining features of eukaryotic cells (e.g., presence of nucleus, membrane-bound organelles).

3. Compare and contrast plant and animal cells, focusing on structures like cell wall, chloroplasts, and vacuoles.

4. Summarize the main differences in a table or chart for clarity.

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