Photo AI
5. (a) (i) In relation to structures such as the cell membrane, explain the term selective permeability - Leaving Cert Biology - Question 5 - 2013
Question 5
5. (a) (i) In relation to structures such as the cell membrane, explain the term selective permeability. (ii) Suggest an advantage to the cell of having a selective... show full transcript
Worked Solution & Example Answer:5. (a) (i) 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.
Answer
Selective permeability refers to the ability of the cell membrane to allow only certain substances to pass through while blocking others. This means that the membrane can control which molecules enter or exit the cell, maintaining the internal environment by preventing unwanted substances from entering and allowing necessary substances, such as nutrients and gases, to pass in.
Step 2
Suggest an advantage to the cell of having a selectively permeable membrane.
Answer
An advantage of having a selectively permeable membrane is that it helps the cell to maintain homeostasis. By selectively allowing substances to enter or exit, the cell can keep a stable internal environment, which is essential for proper function and survival. This regulation can prevent the loss of important ions and nutrients while facilitating the removal of waste products.
Step 3
Step 4
Explain the term turgor.
Answer
Turgor is the pressure exerted by the fluid (usually water) inside the central vacuole of a plant cell against the cell wall. This pressure helps maintain the rigidity and structural integrity of the plant. The greater the turgor pressure, the firmer and more upright the plant appears.
Step 5
Give a feature of a plant cell that allows it to remain turgid for long periods.
Answer
A feature of a plant cell that allows it to remain turgid for long periods is the presence of a large central vacuole filled with cell sap. This vacuole can store water and maintain pressure against the cell wall, helping to keep the cell turgid.
Step 6
Suggest a way in which turgor is of value to plants.
Answer
Turgor is of value to plants as it provides structural support, allowing them to stand upright and grow towards sunlight for optimal photosynthesis. Additionally, turgor pressure is essential for the growth of plant cells as it helps them expand and maintain their shape.