Thank you for the opportunity to help you with your question!
Proteins are the other major constituent of cell membranes, constituting
25 to 75% of the mass of the various membranes of the cell hence membrane proteins determines how a molecule interacts with
the cell membrane.
A small cell has a large SA:V ratio and therefore can exchange molecules with it's external environment rapidly.
however, ions and water can be lost by diffusion and osmosis, and heat can be lost at a faster rate.
a large cell has a small SA:V ratio and therefore exchanges molecules with it's external environment slowly.
large cells are less efficient as often they cannot obtain enough oxygen and nutrients for their needs.
The three steps in any kind of signal transduction whether in animals or plants is:
The Signal transduction process must involve three stages.
1. In reception, a chemical signal binds to a cellular protein, typically at the cell’s surface.
2. In transduction, binding leads to a change in the receptor that triggers a series of changes along a signal-transduction pathway (say starting with formation of cyclic AMP to activation of kinases).
3. In response, the transduced signal (say kind of various kinases) triggers a specific cellular activity (say cell elongation by auxin in plants).
4.Ligand binding to a receptor (receptor protein) alters its chemical conformation (three-dimensional shape). The conformational state of a receptor protein determines its functional state. Ligands include substrates, inhibitors, activators, and neurotransmitters. The tendency or strength of binding is called affinity. Binding affinity is determined not only by direct interactions, but also by solvent effects that can play a dominant indirect role in driving non-covalent binding in solution
5. Epinephrine is also known as adrenaline. It is a hormone that is secreted by the adrenal gland. Epinephrine is secreted when stressed.
when reaches liver cells, it binds to a G protein-coupled receptor in
the plasma membrane. triggers a cascade of events, leading to cell
releasing glucose into bloodstream.
hey, hope i was able to help you with my answers
Content will be erased after question is completed.