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4. (a) What is the function of the membrane in cellular processes? (i) Describe its role as a barrier - Leaving Cert Home Economics - Question 4 - 2018
Question 4
4. (a) What is the function of the membrane in cellular processes? (i) Describe its role as a barrier. (ii) Explain how it facilitates the movement of substanc... show full transcript
Worked Solution & Example Answer:4. (a) What is the function of the membrane in cellular processes? (i) Describe its role as a barrier - Leaving Cert Home Economics - Question 4 - 2018
Step 1
Describe its role as a barrier.
Answer
The membrane serves as a selective barrier that regulates what enters and exits the cell. It allows essential nutrients to pass through while keeping harmful substances out. This selective permeability is crucial for maintaining the cell's internal environment and homeostasis.
Step 2
Explain how it facilitates the movement of substances.
Answer
The membrane contains various proteins that facilitate the transport of substances in and out of the cell. These include channel proteins for passive transport and carrier proteins for active transport. Additionally, the membrane's phospholipid bilayer allows certain small nonpolar molecules to diffuse freely across.
Step 3
Explain how the structure of the membrane is suited for its function.
Answer
The structure of the membrane, particularly the phospholipid bilayer with embedded proteins, is suited for its function because it forms a flexible yet stable barrier. The hydrophobic interior of the bilayer prevents the free passage of water-soluble substances, while the integral and peripheral proteins facilitate specific interactions and transport processes. This arrangement enables the membrane to maintain homeostasis while allowing communication and exchange with the external environment.
Step 4
Explain the advantages of using the fluid mosaic model in understanding cell membranes.
Answer
The fluid mosaic model provides a comprehensive understanding of the cell membrane by depicting it as a dynamic and flexible structure, where lipids and proteins can move laterally. This model accounts for the heterogeneous composition of membranes and the functions of various proteins, including receptors, enzymes, and transport proteins. It helps explain the membrane's adaptability and fluidity, which are essential for cellular functions like signaling and transport.