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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 draw the ciliated epithelial cell, start by sketching an elongated shape to represent the cell body. Then, include three distinct parts with labels:
- Cilia: Draw hair-like projections on the surface of the cell, labeled 'Cilia'. Cilia are responsible for moving mucus and trapped particles out of the respiratory tract.
- Nucleus: Indicate a round structure within the cell, labeled 'Nucleus'. The nucleus contains the cell's genetic material and controls its activities.
- Cytoplasm: Shade the area inside the cell to represent the cytoplasm, labeled 'Cytoplasm'. Cytoplasm is the jelly-like substance that holds organelles and is the site for many cellular processes.
Step 2
State the function of the ciliated epithelial cells in the airways of the human breathing system.
Answer
The primary function of ciliated epithelial cells in the airways is to trap and expel foreign particles, such as dust and pathogens, from the respiratory system. The cilia beat in a coordinated manner to move mucus upwards towards the throat, ensuring that the airways remain clear and helping to prevent infections.
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:
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Measure the movement of the coloured liquid drop in mm from Figure 5 (e.g., if it moved 3 cm, convert to mm, which is 30 mm).
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Divide the distance moved (in mm) by the time taken (10 minutes) to find the rate:
For example:
Step 4
Describe a control for this investigation.
Answer
A suitable control for this investigation could involve setting up a similar experiment with a stationary test tube containing the same amount of liquid and without any maggots. This would allow comparison to determine if the movement of the coloured liquid is due to respiration or other factors such as temperature changes or pressure changes in the surrounding environment.