Water, the Solvent for Life

水，生命之溶剂

The human body is 66% water by weight, according to Hill and Kolb. Water is the universal solvent for life, referred to by Nobel Laureate A. Szent-Gyorgy as "the matrix of life".That water serves as the solvent for sodium chloride (salt) and other substances so that the fluids of our bodies are similar to sea water. This leads Hill and Kolb to refer jokingly to us as "walking bags of sea water". Water serves to suspend the red blood cells to carry oxygen to the cells. It is the solvent for the electrolytes and nutrients needed by the cells, and also the solvent to carry waste material away from the cells.

根据Hill和Kolb的说法，人体的重量百分比中有66%是水。水是生命中的通用溶剂，诺贝尔奖得主A. Szent-Gyorgy称其为“生命的基质”。水作为氯化钠（盐）和其他物质的溶剂，使得人体的液体类似于海水。这使得Hill和Kolb开玩笑地称我们为“行走的海水袋”。水用于悬浮红血细胞以将氧气输送到细胞中。它也是细胞所需电解质和营养物质的溶剂，同时也是将废物从细胞中运走的溶剂。

With water as the solvent, osmotic pressure acts to transport the needed water into cells. With cells bathed in the interstitial fluid, diffusion contributes to carrying needed molecules into the cells. When more complex mechanisms control the transport of molecules across the membranes into and out of cells, the presence of water as the surrounding medium and solvent is essential.

当水作为溶剂时，渗透压会促使所需水分进入细胞。当细胞浸浴在Interstitial fluid中时，扩散有助于将所需分子带入细胞。当更复杂的机制控制分子跨膜运输进入和离开细胞时，水作为周围介质和溶剂的存在是必不可少的。

Water as a Polar Molecule

水作为极性分子

Hydrogen forms covalent bonds with oxygen to form the H₂O molecule, but oxygen has a higher electronegativity than hydrogen, so it takes a larger portion of the shared electron charge.

This polar nature of the water molecule is crucial to it's stability in liquid form at the temperatures needed for life, and for its activity as a solvent for biologically related molecules. A measure of the polar nature of the water molecule is its dipole moment. The nature of the internal interactions in water is described in terms of dipolar bonding.

水分子的极性对其在生命所需温度下保持液态的稳定性以及作为生物相关分子的溶剂的活性至关重要。水分子极性的量度是其偶极矩。水内部相互作用的性质则通过偶极键来描述。

Hydrogen bonding between the water molecules in the liquid state contributes to its viscosity, its density, and surface tension. The strength of this internal bonding contributes to the high specific heat of water.

液态水中水分子之间的氢键作用贡献于其粘度、密度和表面张力。这种内部键的强度也导致了水的高比热容。

氢与氧形成共价键以形成H₂O分子，但氧的电负性比氢高，因此它会占据更多的共享电子电荷。

Hydrogen Bonds and Solvent Action

氢键与溶剂作用

The polar nature of the water molecules causes them to be attracted to molecules such as sodium chloride which have ionic bonds.

水分子的极性使它们被具有离子键的分子（如氯化钠）所吸引。

The strength of the attraction to the polar water molecules is sufficient to separate the Na⁺ and Cl^- into free ions. Such ions are important in biochemistry where they are transported in cellular membrane processes and in nerve functions such as action potentials.

对极性水分子的吸引力足以将Na⁺和Cl⁻分离为自由离子。这些离子在生物化学中非常重要，它们参与细胞膜过程中的运输以及神经功能，如动作电位。

The molecules of sugars have OH groups which can interact with the charges of water molecules to create hydrogen bonds. The forces of these hydrogen bonds can separate molecules of sugar, so most sugars are readily soluble in water. This is particularly important with glucose so that it can move freely in the blood vessels to provide energy to the body.

糖分子中含有羟基，可以与水分子的电荷相互作用形成氢键。这些氢键的力足以使糖分子分离，因此大多数糖都能很好地溶于水。这一点在葡萄糖中尤为重要，因为它可以自由地在血管中移动，为身体提供能量。