you have isolated a yeast strain with a genetic mutation that increases the hydrophobic nature of the…

you have isolated a yeast strain with a genetic mutation that increases the hydrophobic nature of the transmembrane domains of one of its ion channels. what is the most probable outcome? less energy will be required to move the ion across the membrane. ion channel specificity will change to allow different ions across the membrane. more energy will be required to move the ion across the membrane. the diffusion rate of the ion across the membrane will decrease. the diffusion rate of the ion across the membrane will increase.

you have isolated a yeast strain with a genetic mutation that increases the hydrophobic nature of the transmembrane domains of one of its ion channels. what is the most probable outcome? less energy will be required to move the ion across the membrane. ion channel specificity will change to allow different ions across the membrane. more energy will be required to move the ion across the membrane. the diffusion rate of the ion across the membrane will decrease. the diffusion rate of the ion across the membrane will increase.

Answer

Brief Explanations:

Ion channels are proteins that facilitate the movement of ions across the membrane. The transmembrane domains interact with the lipid bilayer (which is hydrophobic). If the transmembrane domains become more hydrophobic, they will integrate more tightly into the lipid bilayer. This tighter integration can restrict the movement of ions through the channel. Diffusion rate is related to how easily ions can pass through the channel. A more restricted channel (due to tighter membrane - channel interaction) will decrease the diffusion rate of ions across the membrane.

  • Option 1: Ion channels are for facilitated diffusion (passive in most cases, no energy required for ion movement through the channel). Hydrophobicity of the transmembrane domain does not directly relate to energy for ion movement.
  • Option 2: Hydrophobicity of the transmembrane domain is not related to ion - channel specificity (specificity is usually due to the shape and charge of the ion - binding sites in the channel, not the hydrophobicity of the transmembrane part).
  • Option 3: As mentioned, ion movement through channels (in simple cases) is passive (no energy input for ion movement). Hydrophobicity of the transmembrane domain does not make energy required for ion movement.
  • Option 5: A more hydrophobic transmembrane domain would likely restrict ion movement, so diffusion rate would decrease, not increase.

Answer:

The diffusion rate of the ion across the membrane will decrease.