<span>Of the 118 elements that have been discovered, 90 of them indisputably occur in nature. There is disagreement over whether four more or eight more occur naturally as a result of radioactive decay of other natural elements. The answer is, therefore, 94 or 98.</span>
<span>An important prelude to a greeting or opening line is often eye contact.</span>
Answer:
Explanation:
Proteins in the plasma membrane have several functions based on their components, location etc. For instance, if the protein transcends the entire plasma membrane it could be a transport protein, responsible for the import and export of certain molecules between the cell and the extracellular matrix (ECM). If the proteins are resting at the surface of the cell, facing the ECM, their role could be to detect components in the ECM, relaying a series of messages back to the nucleus so that the cell can ‘decide’ what it should do with this information (is it being told it should undergo apoptosis, should it begin to divide, should it migrate?). As well as this, it could be involved in the detection of foreign bodies such as pathogens. This is an extremely job for these proteins because if the cell does come in contact with a pathogen, the cell can use these proteins to engulf the pathogen and through a series of steps, present the antigen on their major histocompatibility complexes (either 1 or 2 depending on the cell type) or HLA’s for human cells. Thus it can be concluded that protein functions vary widely in the plasma membrane and due to the vast number of proteins that can be found there, it’s difficult to narrow down the exact main of functions of all these proteins put together.
The answer is diffusion.
The most important mechanism that enables oxygen and carbon dioxide (but as well other small molecules such as glucose, amino acids, wastes) across capillary walls is diffusion. Diffusion is a net movement of molecules through some barrier from an area of high concentration to the area of low concentration. When blood rich in oxygen reaches capillaries close to the cell, now there <span>is </span>more oxygen in the capillaries than in the cells and by diffusion, oxygen will pass capillary walls and enter the cell. Since blood in capillaries lacks in carbon dioxide, it will easily leave the cells and enter the blood. It should be taken into consideration that capillary walls may be fenestrated, continuous, and discontinuous which can affect movement through them.
Answer:
it is known as the powerhouse of he cell
Explanation:
this is because it extracts energy from food through cellular respiration
