biolgist concludes that a molecule moves across cell membrane by facilitated diffusion because the molecule is small, polar and can accumulate inside cells even when its concentration inside the cell initially is higher that it is outside the cell and they use up more energy when the molecule is present in the environment around the cells than when it is not present. Agree or disagree? why or why not? confused....thanks for your help
Based on the information provided, I agree with the biologist's conclusion that the molecule moves across the cell membrane by facilitated diffusion. Here's why:
1. The molecule is small: Facilitated diffusion is a type of passive transport in which specific carrier proteins help move molecules across the cell membrane. These proteins have specific binding sites for certain molecules, usually smaller ones, to facilitate their movement.
2. The molecule is polar: The cell membrane is composed of a lipid bilayer, which creates a hydrophobic (non-polar) environment. Polar molecules have difficulty crossing this barrier, so special transport proteins are required for their facilitated diffusion.
3. The molecule can accumulate inside cells even when its concentration initially is higher inside the cell than outside: Facilitated diffusion is a passive process driven by the concentration gradient. If the molecule is small and polar, it will have difficulty diffusing across the cell membrane on its own. However, the presence of transport proteins allows it to passively move inside the cell, even when the concentration gradient is against its favor.
4. More energy is used up when the molecule is present in the environment around the cells: This statement implies that the presence of the molecule has an effect on cellular processes, likely through interaction with cellular components or processes. This aligns with the idea that the molecule is able to enter the cell through facilitated diffusion and exert an influence on cellular function, resulting in increased energy usage.
In summary, the biologist's conclusion is supported by the characteristics of the molecule (small and polar) as well as its ability to accumulate inside cells despite a concentration gradient disadvantage and its impact on energy usage in the cell's environment.