Question 1: Define a bacterial cell and describe one key difference between bacterial cells and plant cells.

Answer: A bacterial cell is a prokaryotic microorganism that lacks a nucleus. One key difference is that bacterial cells do not have membrane-bound organelles like a nucleus or chloroplasts.

Question 2: Explain the role of the cell wall in bacterial cells.

Answer: The cell wall provides structural support and protection, maintaining the shape of the bacterial cell and preventing it from bursting due to osmotic pressure.

Question 3: What is the main genetic material in bacterial cells, and where is it located?

Answer: The main genetic material is a single circular DNA molecule located in the nucleoid region of the cytoplasm.

Question 4: A scientist isolates a bacterial sample and finds that it has a flagellum. What is the function of this structure?

Answer: The flagellum enables the bacterial cell to move by acting like a whip or motor, helping it navigate its environment.

Question 5: Calculate the surface area to volume ratio of a spherical bacterial cell with a radius of 1 micrometer. (Use the formulas: Surface Area = 4πr², Volume = (4/3)πr³)

Answer: Surface Area = 4 * π * (1 μm)^2 ≈ 12.57 μm²; Volume = (4/3) * π * (1 μm)^3 ≈ 4.19 μm³; Ratio = Surface Area / Volume ≈ 3.00

Question 6: Identify three safety precautions to consider when working with bacterial cultures in a laboratory setting.

Answer: Wearing gloves and lab coats, sterilizing equipment before use, and working in a sterile environment to prevent contamination.

Question 7: Describe a simple experiment to test the effect of pH on bacterial growth. Include the variables involved.

Answer: Set up several nutrient agar plates with different pH levels (e.g., pH 5, 7, 9). Inoculate each plate with the same bacterial sample and incubate under identical conditions. The independent variable is the pH level; the dependent variable is bacterial growth (colony size or number); the controlled variables include temperature, inoculum size, and incubation time.

Question 8: Based on data collected from an experiment, a bacterial culture grew most rapidly at pH 7. What does this suggest about the optimal pH for this bacterium?

Answer: It suggests that the optimal pH for the growth of this bacterium is neutral, around pH 7.

Question 9: In industry, bacterial cells are used in the production of certain products. Name one product and describe the role bacteria play in its production.

Answer: Yogurt is produced using bacteria such as Lactobacillus; these bacteria ferment lactose to produce lactic acid, which thickens the milk and gives yogurt its flavor.

Question 10: How does understanding bacterial cell structure help in developing antibiotics?

Answer: Knowing bacterial cell structures, such as the cell wall and enzymes, allows scientists to design antibiotics that target these structures and inhibit bacterial growth without harming human cells.