Question: The model shows two types of proteins, channels and carriers, allowing the movement of molecules into the cell. As indicated by the model, what question is best asked about the role of the proteins in this type of transport? A) How can proteins be used in active transport? B) How do proteins allow for endocytosis of large molecules? C) How can molecules move against the gradient through proteins? D) How do proteins allow for facilitated diffusion of molecules into the cell?
The question will be "D) How do proteins allow for facilitated diffusion of molecules into the cell?"
Explanation:
Since proteins are being used but energy is not, this process is called facilitated diffusion. Protein channels and carriers are both types of facilitated diffusion. Simple diffusion does not require energy: facilitated diffusion requires a source of ATP. Simple diffusion can only move material in the direction of a concentration gradient; facilitated diffusion moves materials with and against a concentration gradient.
The lateral corticospinal tract functions
in the control of distal muscles such as those of the limbs and the trunk. About
90% of the fibers that travel in the corticospinal tract are found in the
lateral corticospinal tract which makes it the main component of the corticospinal
tract.
