The cell membrane separates the intracellular environment from the extracellular environment outside of the cell. A phospholipid is composed of a phosphate group and a lipid. It is composed of a hydrophilic, polar phosphate head and two hydrophobic fatty acid tails.
The structure of the bilayer is such that the tails are shielded from contact with water, creating a selectively-permeable barrier which will be impermeable to most hydrophilic molecules.
So, the answer is A) To maintain balance of water and nutrients in the cell.
Answer:
Animal cells have slight differences to the eukaryotic cells of plants and fungi. The clear differences are the lack of cell walls, chloroplasts and vacuoles and the presence of flagella, lysosomes and centrosomes in animal cells. Plant and fungal cells have cell walls
Properties of Salt
Crystals or white crystalline powder.
Transparent and colourless in crystalline form – rather like ice.
Crystallises in the isometric system, usually in the form of cubes.
Soluble in water (35.6g/100g at 0°C and 39.2g/100g at 100°).
Slightly soluble in alcohol, but insoluble in concentrated hydrochloric acid.
Chemical factors: This is due to internal stimuli. Changes in the blood such as decrease in O2, increase in CO2 and decrease in PH cause impulse in the carotid artery which stimulates the respiratory centers in the medulla and cause breathing.
Mechanical factors: also called external stimuli. Compression of the fetal chest during delivery forces small amount of lung fluid out of the lungs. This increase in pressure in the chest draws air into the lungs.
