Answer is hypertonic.
The ability of an extracellular solution to make water move into or out of a cell by osmosis is known as its tonicity. Tonicity is concern for all living things, especially in in organisms lacking cell wall, <em>Paramecium</em> is one such protozoan. It has specialized structures called contractile vacuoles. A contractile vacuole collects excess water from the cell and release it out, keeping the cell from lysing as it takes on water from extracellular environment which hypotonic (a lower osmolarity than the cell’s cytoplasm) as compared to hypertonic environment inside <em>Paramecium</em>.
Regulation of HMG-CoA reductase is termed as the rate of controlling enzyme of the mevalonate pathway which produces other isoprenoid and cholesterol.
The regulation of cholesterol is done by regulating the rate which determines step catalyzed by HGM -CoA reductase.
There is long-term and short-term regulation where HGM-CoA is inhibited by phosphorylation and catalyzed of proteins. There is regulated proteolysis of HGM-CoA reductase where degradation of HMG-CoA reductase by oxidized derivatives of cholesterol.
Sunlight is the main energy source
