Question

Draw two bar graphs, one representing the ratio of saturated to unsaturated fatty acids present in the cell membrane and the other representing the amount of cholesterol present in the cell membrane. Each graph should include a bar for each of the following groups of organisms. The objective is to correctly represent what we would expect to see in the cell membranes of organisms adapted to different temperatures. (15 Points) A. Rattlesnakes that have lived for several generations in Canada B. Rattlesnakes that have lived for several generations in Central America C. Rattlesnakes that have lived for several generations in Nebraska D. Rattlesnakes that have lived for several generation in Canada but recently moved to Central America 2. A milliosmole (mOsm) is a measurement of amount of solute in a liquid. Fish face the problem of maintaining a constant internal environment based upon what type of water they live in. The following table shows the mOsm a fish must maintain and their liquid surroundings: (15 Points) Liquid Milliosmole (mOsm) Concentration Salt water 1000-12000 Freshwater 0-10 Freshwater Fish Internal Enviroment 300 Salt water Fish Internal Enviroment 300 A. A freshwater fish must maintain an internal solute concentration of 300 mOsm yet live in an environment where the solute concentration is much lower. What challenges do freshwater fish face with water and solute retention/loss in relation to their environment? What will water do in this scenario? Assume that the solutes do not diffuse into and out of the fish. Draw a picture of a fish; label the internal solute concentration of the fish and the solute concentration of the environment surrounding the fish. Show the direction in which water will move in this scenario. B. A salt water fish must maintain an internal solute concentration of 300 mOsm yet live in an environment where the solute concentration is much higher. What challenges do salt water fish face with water and solute retention/loss in relation to their environment? What will water do in this scenario? Assume that the solutes do not diffuse into and out of the fish. Draw a picture of a fish; label the internal solute concentration of the fish and the solute concentration of the environment surrounding the fish. Show the direction in which water will move in this scenario. C. Fish gills have a huge amount of surface area in order to increase the area for gas exchange. In addition to exchanging gas, solutes (such as Na+ and Cl‐) can be pumped into or out of the gills. Water can also be drank and urinated out by fish. Taking this into consideration, diagram what a salt water and a freshwater fish could do to balance the osmosis of water and maintain a constant internal environment in its cells.

measurement of amount of solute in a liquid. Fish face the problem of maintaining a A milliosmole (mOsm) is constant internal environment based upon what type of water they live in. The following table shows the mOsm a fish must maintain and their liquid surroundings: (10 Points total) Milliosmole (mOsm) Concentration Liquid 1000-1200 Saltwater 0-10 Freshwater 300 Freshwater Fish Internal Environment 300 Saltwater Fish Internal Environment A. A freshwater fish must maintain an internal solute concentration of 300 mOsm yet live in an environment where the solute concentration is much lower. What challenges do freshwater fish face with water and solute retention/loss in relation to their environment? What will water do in this scenario? Assume that the solutes do not diffuse into and out of the fish. Draw a picture of a fish; label the internal solute concentration of the fish and the solute concentration of the environment surrounding the fish. Show the direction in which water will move in this scenario. (5 points)

Answer 1

Specially in freshwater fish, the water is continuously flowing into the fish's body to dilute the amount of salt in the internal environment of the fish until it is equal to the amount of salt in the external environment. Fish can not allow their salt content to be diminishes, in this case the kidneys are working overtime to expel excess water. Additionally, this kind of fish never drink water because their bodies are saltier than the surrounding water. So osmosis will draw the water into the fish body through its skin and gills. External solute <300 Internal solute 300 mOsm External water Exceed of water is excreted (kidneys overwork)