Ion Exchange 1 Flashcards
What is ionic balance responsible for
Maintaining cell shape & resting membrane potential
What is pH balance responsible for
Protein folding & enyzme functions within restricted pH ranges
What is nitrogen balance responsible for
Nitrogenous wastes that are converted to toxic ammonia need to be excreted as either ammonia, urea, or uric acid
What do water, ionic, pH, and nitrogen regulation all affect
Blood volume, pressure, and heart function
What are perturbing solutes
Inorganic ions, charged amino acids, ammonia that disrupt macromolecular function
What are compatible solutes
Trehalose, glycerol, glucose, and uncharged amino acids. Do not disrupt function, even at high concentrations.
What are counteracting solutes
Harmful individually, but in combination are not harmful (Urea, methylamines such as TMAO)
Can you actively transport water
NO
Water follows ___
Solute
If you move ions into the cell, water moves __
Into the cell
If you move ions out of the cell, water moves ___
Out of the cell
How much water can pass through an aquaporin in one second
1 billion water molecules
What type of cells play a role in regulating salt-water balance in animals
Epithelial cells
How do solutes move across epithelial cells
Transcellular & Paracellular transport
What are four properties of epithelial cells
- Asymmetric distribution of transporters/channels
- Junctions regulating paracellular transport
- Diversity of epithelial cell types
- High mitochondrial density to provide ATP for ATPase pumps
What are osmoconformers
Marine invertebrates that have an osmolarity equal to that of ocean water. They do not control the osmotic condition of their body fluids (crab, squid)
What are osmoregulators
Animals that actively control their osmotic fluid, but have an osmolarity isotonic to the ocean. Less NaCl, but lots more urea. (Shark, tuna)
How do freshwater fish osmoregulate
Water moves into fish, so fish does NOT drink. Actively pumps solutes into body
How do salt water fish osmoregulate
Water moves out of fish, so fishes continuously drink water. Salt is actively excreted.
Some fish (chondrichthyes, agnatha) maintain osmotic pressure at or above their environment
Most fish (teleosts) maintain osmotic pressure of body fluids below (marine species) or above (freshwater species) that of their environment.
What are stenohaline fish
restricted to a narrow range of salinity.
What are euryhaline fish
capable of adapting to a wide range of salinities.
Osmoregulatory organs in fish (in order of importance):
Gills, intestines, kidneys
What are chloride cells
Cells in the gill that move ions against large concentration gradients
What are the two types of cells in freshwater fish
PNA-, PNA+ (see slide for transporters and pathways!)
Osmoregulatory problems of tetrapods
Prevention of water loss through evaporation and urine excretion
Osmoregulatory strategies of tetrapods
- Body coverings (thick skin, fur, waxy layers, exoskeletons, shells)
- Nocturnal
- Produce trehalose
- Reduce evaporatative water loss
- Concentrated urine
What is trehalose
Disaccharide that protects cells by replacing water associated with membranes and proteins
Since desert animals (kangaroo rat) do not drink water, how do they have water balance
90% derived from metabolism, 10% from water in seeds (food)
How do you get metabolic water
Metabolism of fat, sugar, and proteins
How much water does 100g of fat produce
107g H20
How much water does 100g of starch (sugar) produce
55g H20
How much water does 100g of protein produce
41g H20
