Biology 2601A/B Lecture Notes - Lecture 19: Electrochemical Gradient, Cotransporter, Blood Plasma

• School: Western University
• Department: Biology
• Course: Biology 2601A/B
• Professor: Graeme Taylor

Document Summary

The fact that human beings are approximately 75% water means that it is important for us to discourage any form of water loss. Referred to in parts per thousand, chloride (cl-) , sodium (na-), sulfate (so4. Magnesium (mg+), calcium (ca2+), and potassium (k+) are the primary constituents found in seawater and make up most of the ions found there (in that order). (note that minor elements are not considered in this course). Many invertebrates such as the cnidarians and annelids possess physiological membranes that are very close or similar to the salt content in sea water. They are said to be isosmotic to sea water salinity (their osmolarity is very similar to sea water). Sharks and cartilaginous fish are very much like the mentioned invertebrates as they are, for the most part, isosmotic with sea water. The hagfish is a primitive, jawless (no paired fins) vertebrate that is quite isosmotic to its saltwater environment.