Question

the model of the plasma membrane is called the fluid mosaic model. it is fluid because the phospholipids move within the membrane just as water molecules move in a lake. at the same time, proteins in the membrane also move among the phospholipids like boats with their decks above water and hulls below water. these proteins create a “mosaic,” or pattern, on the membrane surface. other components of the plasma membrane cholesterol, shown in figure 7.5, is also found in the plasma membrane and it helps to stabilize the phospholipids by preventing their fatty tails from sticking together. reading check explain how a water - soluble substance can pass through the plasma membrane. section assessment thinking critically 5. suggest what might happen if cells grow and reproduce in an environment where no cholesterol is available.

Explanation:

Water - soluble substances cannot pass directly through the non - polar lipid bilayer of the plasma membrane. They require transport proteins (such as channel proteins or carrier proteins) to facilitate their passage. These proteins create hydrophilic pathways or bind to the substances and transport them across the membrane. Without cholesterol in the plasma membrane, the membrane would lack stability. The fatty acid tails of phospholipids might stick together more easily, reducing membrane fluidity and flexibility. This could affect the function of membrane - bound proteins, including transport proteins, and potentially disrupt normal cellular processes such as nutrient uptake and waste removal.

Answer:

To pass through the plasma membrane, a water - soluble substance needs to use transport proteins (channel or carrier proteins). If cells grow and reproduce in an environment with no cholesterol, the plasma membrane may lose stability, have reduced fluidity, and normal cellular functions related to membrane proteins may be disrupted.