process the balances the uptake and loss of water. It is under homeostatic control.
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What is the difference between passive and active transport?
Passive- along a concentration gradient (high to low). Active- against a concentration gradient (requires energy).
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How does temperature influence passive rate?
higher temperature = faster rate.
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How does particle size influence passive rate?
smaller particles = faster rate.
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How does electrical charge of ions influence passive rate?
can facilitate passive movement (-ve attracts to +ve). can also prevent passage.
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How does concentration gradient influence passive rate?
greater gradient = faster rate.
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What is Osmolarity?
measure of the osmotic pressure exerted by a solution across a perfect semi-permeable membrane compared to pure water. (it is a measure of solute concentration)
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What is a perfect semi-permeable membrane?
a membrane that will only allow water to cross.
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What is the osmolarity of pure water and what happens to that value when solutes are added?
0. this will increase if solutes are added.
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How is Osmolarity calculated?
= (no. of particles/molecules of solute) X (moles/litres)
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What is Osmolarity measured in?
osmoles per litre (Osm/l)
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What can we use osmolarity for in terms of physiology?
to describe the difference between the extracellular fluid and the cell.
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What is Tonicity?
the effect of a solution on a cell volume
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What are Osmoconformers? Give examples?
osmolarity of body fluid matches that of the environment. eg. marine invertebrates and elasmobranches
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What are Osmoregulators? Give examples?
osmolarity of body fluid regulated to within set range (doesn't match environment). eg. mammals, birds, most marine and freshwater teleosts.
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What are limited osmoregulators? give examples?
have limited ability to regulate osmolarity of body fluid. eg. some fish and amphibians, freshwater and brackish invertebrates.
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A marine teleost is ?-osmotic to the environment?
hypo-osmotic. (environment has low water concentration, high salt concentration.)
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Why is this problematic for the marine teleost and how do they solve it?
they are losing water. To solve this, they consume large quantities of sea water. Active removal of salts through gills. Small amounts of urine.
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Freshwater teleost is ?-osmotic to the environment?
hyper-osmotic. (environment has high water concentration, low salt concentration).
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Why is this problematic for the freshwater teleosts and how do they solve this?
they are gaining too much water. To solve this, they excrete large amounts of dilute urine. Active take up of salts through gills.
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Other cards in this set
Card 2
Front
What is the difference between passive and active transport?
Back
Passive- along a concentration gradient (high to low). Active- against a concentration gradient (requires energy).
Card 3
Front
How does temperature influence passive rate?
Back
Card 4
Front
How does particle size influence passive rate?
Back
Card 5
Front
How does electrical charge of ions influence passive rate?
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