Lab Analysis
Learning Objectives
In this lesson, you will practice analyzing experimental data related to cell biology, including interpreting graphs, tables, and experimental results.
- Interpret data from cell biology experiments
- Analyze graphs showing cellular respiration rates
- Draw conclusions from experimental observations
- Identify variables and controls in cell biology experiments
Sample Lab Scenario
Experiment: Effect of Temperature on Cellular Respiration
Background: A student investigated how temperature affects the rate of cellular respiration in yeast cells by measuring CO2 production.
| Temperature (C) | CO2 Produced (mL/hour) |
|---|---|
| 10 | 2.1 |
| 20 | 5.8 |
| 30 | 12.4 |
| 40 | 18.7 |
| 50 | 8.2 |
| 60 | 1.3 |
Analysis Questions to Consider:
- What is the independent variable? (Temperature)
- What is the dependent variable? (CO2 production)
- At what temperature was respiration highest? (40C)
- Why does respiration decrease at high temperatures? (Enzyme denaturation)
Practice Quiz
Test your lab analysis skills with these 10 questions. Click on each question to reveal the answer.
1. In the yeast experiment above, why did CO2 production increase from 10C to 40C?
Answer: Enzymes involved in cellular respiration work faster at higher temperatures (up to an optimal point) because molecules have more kinetic energy, resulting in more frequent and successful collisions.
2. Why did CO2 production decrease dramatically at 50C and 60C?
Answer: At these high temperatures, the enzymes involved in cellular respiration begin to denature (lose their shape), which reduces their ability to catalyze reactions effectively.
3. What control should be included in this experiment?
Answer: A control group at room temperature (approximately 20-25C) or a tube with no yeast should be included to compare results and ensure CO2 is coming from yeast metabolism.
4. A microscope observation shows cells with many green, disc-shaped organelles. What type of cell is this, and what are these organelles?
Answer: This is a plant cell, and the green disc-shaped organelles are chloroplasts, which contain chlorophyll and are the site of photosynthesis.
5. If you wanted to measure the rate of photosynthesis instead of cellular respiration, what would you measure?
Answer: You could measure oxygen production (O2 is a product of photosynthesis) or CO2 consumption, or you could measure the rate of glucose production.
6. A student places cells in a hypertonic solution and observes them shrinking. What cellular process is occurring?
Answer: Osmosis. Water is moving out of the cells into the hypertonic solution because the solution has a higher solute concentration than the cell's cytoplasm.
7. In an electron micrograph, a student counts 50 mitochondria in a muscle cell but only 10 in a skin cell of the same size. What does this suggest?
Answer: Muscle cells require more ATP/energy for contraction, so they have more mitochondria to produce the necessary ATP through cellular respiration.
8. A researcher adds a chemical that blocks the electron transport chain. What effect would this have on ATP production?
Answer: ATP production would decrease dramatically because the electron transport chain produces most of the ATP (about 34 of 36-38 total ATP molecules) during cellular respiration.
9. If the data in a cell respiration experiment showed no change in CO2 production at any temperature, what might have gone wrong?
Answer: Possible issues include: dead yeast cells, no glucose substrate provided, equipment malfunction, or the yeast may have been killed during preparation.
10. Why is it important to keep all variables except temperature constant in the yeast experiment?
Answer: To ensure that any changes in CO2 production are due to temperature changes only. If other variables (like glucose concentration or yeast amount) varied, you couldn't determine which variable caused the results.
Next Steps
- Practice identifying variables in other experiments
- Continue to the Claim-Evidence Writing lesson
- Review graphing and data analysis skills