Question

how does the presence of a transport protein change the categorization of a molecules movement from simple diffusion to facilitated diffusion? the transport protein enables the movement of substances (like polar or large molecules) that cannot pass the membranes core on their own. the transport protein reverses the direction of movement, forcing the solute to move up the concentration gradient. the transport protein changes the process from passive transport to active transport. the transport protein only allows the movement of water molecules, thereby transforming the process into osmosis. a healthcare worker is accidentally exposed to a dangerous, fast - acting virus. a doctor must choose between administering a vaccine (active immunization) or an injection of antibodies (passive immunity). in this emergency situation, why might the doctor choose the antibody injection? the antibody injection provides permanent immunity, while the vaccine is only temporary. the antibody injection provides immediate, though temporary, protection, which is critical against a fast - acting virus. the antibody injection is always cheaper and easier to get than a vaccine. the vaccine would cause a serious illness in a person already exposed to the virus.

Explanation:

1. For the first question, simple diffusion is the passive movement of small, non - polar molecules across a membrane. Transport proteins in facilitated diffusion help polar or large molecules that cannot cross the lipid - based membrane core unaided to move across the membrane down their concentration gradient, still a passive process.
2. For the second question, passive immunity from antibody injection provides immediate protection as pre - formed antibodies are introduced. In contrast, active immunization from a vaccine takes time for the body to produce its own antibodies. In an emergency with a fast - acting virus, immediate protection is crucial.

Answer:

1. The transport protein enables the movement of substances (like polar or large molecules) that cannot pass the membrane's core on their own.
2. The antibody injection provides immediate, though temporary, protection, which is critical against a fast - acting virus.