A prolonged drought.
I think it is A, a prolonged drought because you have limit to water, so that is the limited factor. Hope this helps!
Answer: Transducting the signal from an activated receptor to the next protein in the pathway.
Explanation:
G-proteins are a family of proteins whose main function is to carry a signal from a receptor on the cell membrane to one or more target proteins. So, G-proteins are very important in signal transduction. They depend on the nucleotide guanosine triphosphate (GTP) for activation.
They are the third largest family of proteins in eukaryotic cells and hundreds have been described. G-proteins are involved in signal transduction in many different ways, which is why there are so many different types of these proteins. <u>They can be involved in signalling the activation or silencing of DNA translation, in the reception of hormonal and neuronal signals, etc.</u> They are characterized by their interaction with guanosine triphosphate (GTP) leading to hydrolysis of the nucleotide to guanosine diphosphate (GDP). In this way, a stimulus from outside the cell, a ligand for example, accesses the cell's receptor associated with G-protein or GPCR, triggering a cascade of enzymatic activities or second messengers in response. Therefore, GTPase activity is crucial for their functioning as biological switches.
G-protein-coupled receptors (GPCR) comprise the targets of several biogenic amines, eicosanoids, and other molecules that send signals to target cells such as lipids, hormonal peptides, opiates, amino acids (GABA), and many other protein peptides and ligands. Effectors that are regulated by G-protein include enzymes such as adenyl cyclase, phospholipase C, phosphodiesterases and plasma membrane ion channels selective for Ca²+ and K+.
Also, because of their number and physiological importance, GPCRs are widely used targets for drugs.
Solvent as a universal solvent
Answer:
Cheek cells lack a rigid cell wall and due to this their shape is not as well defined as a plant cell.
Explanation:
- Cell wall is the outermost structure in plant and bacterial cells.
- The plant cell wall is made up of cellulose and provide rigidity and shape to the cell.
- In animal cell, the cell wall is absent and the outermost part of the cell is the cell memrane.
- This is the reason that most animal cell lack rigidity and shape.
The relative densities of the water as solid and liquid differ from the subsequent densities of the other substances. The density of the solid form of water is less than the density of water in its liquid form. However, majority of other substances increases in density when they solidify. This is the reason that the ice (which is the solid form of water) floats on water (liquid form).
Hence, the correct answer is 'Water's solid form is less dense than solid form while the case in opposite in other substances'.