Answer:
Then what is the question???
Answer:
They make up carbohydrates.
Lawn and farming fertilizer is harmful to the enviroment due to the abundance of chemicals. When it rain or seeped underground, the fertilizer leaked into the nearby lake and thus, all the fish died to the chemicals in the fertilizer.
I don't think the water cycle has a beginning or ending because all the water in the world is always in various stages of the cycle. It's kind of like asking if a circle has a beginning or ending.
At the very least, I can't think of a specific 'beginning' or 'ending', although I suppose there is an argument to be made that percipitation is the ending and evaporation is the beginning.
Answer:
Ligand-receptor interaction is the first interaction that triggers cell signalling.
Ligands are the hormones, drugs or neurotransmitters that specifically bind with receptors present in cell surface to initiate cell signalling. Ligand binding to the receptor is reversible. Binding of the ligand to the receptor can activate or inactivate receptor. Activation may lead to cell signalling pathways. Inside cells, there are secondary molecules which on activation starts a cascade of reactions. which in-turn regulate the function of the ligand molecule.
At first, the activated receptor relates with G proteins molecules in the cell.
before the ultimate physiological effect of the ligand on the cell's behavior is produced Therefore, the cellular signaling starts as soon as the first messenger (the ligand) binds to its receptor.
hope this helps