Which of the following statements is TRUE?

1. Extracellular signal molecules that are hydrophilic must bind to a cell- surface receptor so as to signal a target cell to change its behavior.
2. To function, all extracellular signal molecules must be transported by their receptor across the plasma membrane into the cytosol.
3. A specific type of type of signal molecule (e.g. acetylcholine) can mediate only one kind of cell response.
4. Any foreign substance that binds to a receptor for a normal signal molecule will always induce the same response that is produced by that signal molecule on the same cell type.
5. I have no idea

Which of the following statements is TRUE?

• Extracellular signal molecules that are hydrophilic must bind to a cell- surface receptor so as to signal a target cell to change its behavior.
• To function, all extracellular signal molecules must be transported by their receptor across the plasma membrane into the cytosol.
• A specific type of type of signal molecule (e.g. acetylcholine) can mediate only one kind of cell response.
• Any foreign substance that binds to a receptor for a normal signal molecule will always induce the same response that is produced by that signal molecule on the same cell type.
• I have no idea

Which of the following statements about molecular switches is false?

1. Phosphatases remove the phosphate from GTP on GTP-binding proteins, turning them off.
2. Protein kinases transfer the terminal phosphate from ATP onto a protein.
3. To become activated, a GTP-binding protein exchanges its bound GDP for GTP.
4. I don’t know

Which of the following statements about molecular switches is false?

• Phosphatases remove the phosphate from GTP on GTP-binding proteins, turning them off.
• Protein kinases transfer the terminal phosphate from ATP onto a protein.
• To become activated, a GTP-binding protein exchanges its bound GDP for GTP.
• I don’t know