Carol Eunmi Lee 2/2/11 Title goes here 1 Outline Last time : Ionic and osmotic regulation in and out of the cell Ion uptake mechanisms This Time : (1) Ionic Regulation and Excretion (3) Ionic and Osmotic Regulation in Different Organisms in Different Environments Ion Uptake The Ion Uptake enzymes are often conserved in amino acid sequence ( often no structural differences) The following are often NOT conserved: Distribution and concentration of Ion Uptake enzymes in a cell The organization of the cells in an organ How can ionic regulation be accomplished through these methods? And can the same organs be involved? What is it?
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Outline - University of Wisconsin–Madison 2009 ReadingWEB/7.Osmoregulation2011.pdf · uptake and excretion mechanisms (see book) In aquatic habitats nitrogenous excretion can occur
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Carol Eunmi Lee 2/2/11
Title goes here 1
Outline Last time: Ionic and osmotic regulation in and out of the cell Ion uptake mechanisms
This Time:
(1) Ionic Regulation and Excretion
(3) Ionic and Osmotic Regulation in Different Organisms in Different Environments
Ion Uptake The Ion Uptake enzymes are often conserved in
amino acid sequence ( often no structural differences)
The following are often NOT conserved: Distribution and concentration of Ion Uptake
enzymes in a cell
The organization of the cells in an organ
How can ionic regulation be accomplished through these methods?
And can the same organs be involved?
What is it?
Carol Eunmi Lee 2/2/11
Title goes here 2
Varies
Amino (-NH2) groups unused from catabolism
Salts and Water
Osmotic concentration depends on Environment
Osmoregulated urine is a convenient way to regulate ionic concentration (through excretion) and remove nitrogenous wastes
Costs and Benefits of different nitrogenous waste products (Table 5.7)
Ammonia: Marine Animals, Inexpensive, water soluble, 1N/molec.(lose less C), permeable thru lipid bilayer, highly toxic
Ionic composition is more conserved across species
Osmotic concentration differs greatly among species: Need to maintain osmotic constancy in and out of the cell, and then try
to approach the osmotic concentration of the environment Using osmolytes or urea to fill Solute Gap with Environment Depends on Environment: Extracellular fluids provide a Buffer
between the cells and the Environment And on Evolutionary History
Marine Invertebrates Extracellular ionic & osmotic concentrations close to sea water Some species do not regulate at all
Intracellular ionic concentration conserved (low) Intracellular osmotic concentration high (Osmotic solute gap filled by osmolytes) High body permeability to water and ions
Isosmotic urine
Extracellular ionic composition is close to seawater (intracellular is not)
Extracellular fluid (blood) concentration 1/4 of marine animal More concentrated than freshwater animal
Not have to worry about loss of ions through osmosis (so osmotic conc. can be higher than in fresh water) Instead, problem of evaporation (water loss through respiration) Mammals: another issue is water used for thermoregulation (sweat)
Terrestrial Vertebrates
Carol Eunmi Lee 2/2/11
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Terrestrial Adaptations!
Active behavioral uptake of water
Ion uptake from food
Skin and cuticle evolved to prevent water loss
Concentrated Urine (kidneys)
Some terrestrial animals can survive water loss (camel- survive 30% loss)
Essentially a terrestrial vertebrate (cow) living in the sea Excrete Concentrated Urine (powerful kidneys)