Answer:
The two main reasons are nonpolar core of the bilayer and the active transport.
Explanation:
The membrane is structured to have two outer layers that are polar and an inner layer that is nonpolar.
If a membrane protein is exposed to the solvent, i<em>t will also have a polar side. It would be very difficult for the polar face of the membrane to move through the nonpolar core of the bilayer.</em> Therefore, this model is not feasible.
One major form of transport, active transport, moves solutes up the concentration gradient. <em>The binding of a solute and then release on another side of the membrane would only work for facilitated diffusion because it would cause a net movement of solutes down the concentration gradient.</em> It is unclear how energy could be expended to drive this process in the transverse carrier model.<em> Therefore, the transverse carrier model does not explain active transport.</em>
Answer:
A.because dna is our blood not sure
Answer:
Cell-mediated immunity develops through a network of interactions that results in defense against microorganisms that survive within phagocytes or other cells. The response is initiated by the recognition of intracellular microorganism antigen by T cells through the histocompatibility complex. In the CD8 response, only the target cell carrying the class I associated antigen can be lysed or induced to apoptosis. In another mechanism of the cellular response, CD4 + Th1 T cells activate, for example, cytokine-infected macrophages such as IFN. When a pathogen resists the effects of activated macrophages, chronic infection may develop.
The hormonal immunity response leads to the destruction of extracellular microorganisms and prevents or decreases the spread of intracellular cells by neutralizing, opsonizing and activating the complement system.
Answer:
The BRCA gene is a tumor-suppressor gene found in the breast; to be more specific, it produces proteins that suppress cancerous activities/abnormal growth in the body. A mutation in a BRCA gene would allow these abnormal growth activities to go unchecked and thus increase the rate of mitosis. Cell cycle checkpoints would significantly be worse at their jobs of checking and correcting for errors during the cell cycle. Tumors would result as well, as cancerous growth continues, and the tumor can become metastatic.
Answer:
The bee at the right is looking for nectar in a flower. While looking for food, this bee is also pollinating the flowers by transferring pollen from the ___anthers__ on one flower to the __stigma__ on another flower.
Explanation:
