<span>The answer is a certain required chemicals must be actively
transported. Blood brain barrier is a
selective membrane that separates blood circulating from the brain and the
fluid of extracellular in the central nervous system. This is also called a
filtering mechanism, the capillaries that carry blood to the brain and spinal
cord tissue blocking the path way of the certain substance.</span>
The two cells of the similar shape, and size have different levels of the ongoing metabolic activity. On one hand, the cell a is metabolically quiet, which means that no energy consuming chemical reactions are taking place in this cell. On the other hand, the cell b is actively consuming the surrounding oxygen. In this scenario, the oxygen will more quickly diffuse into the cell b because the diffusion gradient for oxygen in this cell is steeper than in the cell a.
Hence, the blanks can be filled with 'b and the diffusion gradient is steeper' respectively.
Sleet
Might be wrong lol sorry if it is
Answer:
<u>Pro:</u>
May hold answers to cure various diseases including Alzheimer's and Parkinson's - these may be answers to various diseases that are not able to cure.
Requires a small number of cells because of the fast replication rate - these are able to produce a high amount of cells in the lab as they are able to replicate faster.
Medical benefits such as regenerating organ tissue and therapeutic cell cloning
<u>cons:</u>
ethical controversy over use of stem cells from lab fertilized human egg - there is an ethical controversy around the use of lab fertilized human egg
unproven treatments often come with high rejection rates - these researches provide uncertain results and not tested and easily affected so the rate of rejection is high
The cost can be prohibited for many patients - these require high cost and can not be in the budget of every patient.
