In relation to structures such as the cell membrane, explain the term **selective permeability** - Leaving Cert Biology - Question 5. - 2013
Question 5.
In relation to structures such as the cell membrane, explain the term **selective permeability**.
Suggest an advantage to the cell of having a selectively permeable... show full transcript
Worked Solution & Example Answer:In relation to structures such as the cell membrane, explain the term **selective permeability** - Leaving Cert Biology - Question 5. - 2013
Step 1
In relation to structures such as the cell membrane, explain the term selective permeability.
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Answer
Selective permeability refers to the ability of a cell membrane to allow certain substances to pass through while restricting others. This is essential for maintaining homeostasis within the cell. Through various mechanisms such as passive and active transport, the cell controls the entry and exit of ions, nutrients, and waste products, thus ensuring that only specific molecules are allowed access.
Step 2
Suggest an advantage to the cell of having a selectively permeable membrane.
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Answer
One advantage of having a selectively permeable membrane is that it enables the cell to regulate its internal environment effectively. By controlling which substances can enter or leave, the cell can maintain optimal conditions for processes such as metabolism, osmoregulation, and cellular signaling.
Step 3
Name two substances that enter a human muscle cell by diffusion.
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Two substances that enter a human muscle cell by diffusion are oxygen and glucose. These molecules are essential for cellular respiration and energy production.
Step 4
Explain the term turgor.
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Answer
Turgor refers to the pressure exerted by the fluid (cell sap) inside the central vacuole of a plant cell against the cell wall. This pressure helps maintain the structure and rigidity of the plant, supporting it and allowing it to remain upright.
Step 5
Give a feature of a plant cell that allows it to remain turgid for long periods.
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A key feature that allows a plant cell to remain turgid is its large central vacuole, which stores water and contributes to the internal pressure of the cell. Additionally, the presence of a rigid cell wall further supports turgor pressure.
Step 6
Suggest a way in which turgor is of value to plants.
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Turgor is valuable to plants as it maintains structural integrity and support. It allows plants to stand upright and reach for sunlight, which is crucial for photosynthesis. Moreover, turgor pressure helps in the growth of plant tissues, supporting the expansion of cells and overall growth.
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