Regulating water content

Question 1

What is osmotic concentation?

Answer 1

Total concentration of all solutes in a water solution

Question 2

What is an osmoconformer?

Answer 2

this means water enters and leaves equally, no overall change in water content of organisms

Question 3

What is the concentration like in osmoconformers?

Answer 3

Their internal concentrations of individual solutes are not necessarily the same as in sea water

Question 4

What are sharks?

Answer 4

osmoconformers but can regulate ions

Question 5

What do sharks body fluids have?

Answer 5

almost the same concentration of ions as seawater, but they use different ions

Question 6

What do shark kidneys do?

Answer 6

enables reabsorption of large amounts of urea into the blood, which makes their urine much less concentrated

Question 7

Whar do sharks have to deal with?

Answer 7

a slight influx of salt, which is excreted by a rectal gland

Question 8

What is osmoregulation?

Answer 8

process by which living organisms maintain the solute and water concentration in their blood and body fluids

Question 9

What is the issue with osmoregulators

Answer 9

• Marine vertebrates with osmotic concentrations of solutes lower than that of seawater and so lose water by osmosis through the skin and gain Chloride ions though the skin
• They require mechanisms to maintain their body solute and water content

Question 10

Explain osmoregulation in marine fish

Answer 10

• have an internal solute concentration approx 1/3 of sea water
• tend to lose water (by osmosis) to their environment
• mainly across the permeable gill surface

Question 11

What happens during osmoregulation?

Answer 11

Excess salts in the sea water they drink are absorbed into the blood in the intestine. This causes the plasma to be high in chloride, which would dehydrate cells

Question 12

How is chloride excreted?

Answer 12

-Some salts lost in concentrated urine (hypertonic)

-Sodium and chlorine ions are
actively secreted by chloride
secretory cells (present in gills)

-Process requires energy

Question 13

What does salt form?

Answer 13

sodium ions and chloride ions in the blood of marine fish

Question 14

What do chloride sells absorb?

Answer 14

excess chloride ions from the blood and actively excrete them from the gills (requires ATP and therefore many mitochondria)

Question 15

Why do cell mebranes increase surface area?

Answer 15

for more excretion of chloride ions

Question 16

What is mitochondria used for?

Answer 16

• produce ATP/energy
• ATP is needed for active transport
• site for respiration

Question 17

What is the chloride cell?

Answer 17

Sites of ion transport in fish gills

Question 18

What is euryhaline?

Answer 18

Organisms able to osmoregulate in (tolerate) a range of salinities (can move from salt water to brackish and sometimes fresh)

-Species of fish which migrate from sea into fresh water

Question 19

What do euyhaline organisms use?

Answer 19

Use different mechanisms to control ions in their cells in their different environments

Question 20

Where do salmon spend part of their life cycle?

Answer 20

in fresh water and part in sea water as they reproduce in fresh water and can keep osmotic concentration of their blood stable in both

Question 21

What is the osmotic concentration of blood like in fresh water

Answer 21

It is more concentrated than fresh water

Question 22

What hapens when water enters the fish

Answer 22

it dilutes the blood

Question 23

What difufuses out from the salmon

Answer 23

chloride ions

Question 24

Where are almon able to excreet excess water?

Answer 24

through the kidneys

Question 25

What do salmon uptake through their gills?

Answer 25

chloride

Question 26

What is stenohaline?

Answer 26

organisms that have limited tolerance to changes in salinity (salinity cannot change too much)