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Figure 3 shows ciliated epithelial cells from the airways of a human as seen using a light microscope - Edexcel - GCSE Biology Combined Science - Question 2 - 2021 - Paper 1
Question 2
Figure 3 shows ciliated epithelial cells from the airways of a human as seen using a light microscope. (i) Draw the cell labelled A in the box below. Label three pa... show full transcript
Worked Solution & Example Answer:Figure 3 shows ciliated epithelial cells from the airways of a human as seen using a light microscope - Edexcel - GCSE Biology Combined Science - Question 2 - 2021 - Paper 1
Step 1
Draw the cell labelled A in the box below. Label three parts of this cell on your diagram.
Answer
To answer this question, draw a diagram of a ciliated epithelial cell that reflects its shape and functions. The diagram should include three specific structures:
- Cilia – These hair-like projections on the surface of the cell help in moving mucus and trapped particles out of the airways.
- Nucleus – This structure contains the cell's genetic material and regulates its activities.
- Cytoplasm – This gel-like substance houses organelles and is where many cellular processes occur.
Ensure your drawing is clear and accurately represents the cell, using labels to identify these three parts.
Step 2
State the function of the ciliated epithelial cells in the airways of the human breathing system.
Answer
Ciliated epithelial cells in the airways play a crucial role in protecting the respiratory system. Their primary function is to move mucus, which traps dust, pathogens, and other particles, upward toward the throat. This action helps to keep the airways clear and prevents harmful substances from entering the lungs.
Step 3
Use information from Figures 4 and 5 to calculate the mean rate of respiration of the maggots in mm per minute.
Answer
To calculate the mean rate of respiration, measure the distance moved by the drop of colored liquid in mm (as indicated in Figure 5) over the time elapsed, which is ten minutes. If, for example, the drop moved 3 cm (or 30 mm), the calculation would be:
Thus, the mean rate of respiration would be 3 mm per minute.
Step 4
Describe a control for this investigation.
Answer
A control for this investigation might involve using a setup that includes a similar apparatus without maggots to ensure that any movement of the colored liquid is solely due to the respiration of the maggots. Additionally, maintaining constant environmental conditions, such as temperature and the amount of soda lime, can help ensure that the results are valid and attributable to respiration alone.