Enantiostasis (1 Viewer)

[04er]

Hey I'm having trouble finding information for the following dot point - the part where they ask us to 'discuss its importance':

"define enantiostasis as the maintenance of metabolic and physiological functions in response to variations in the environment and discuss its importance to estuarine organisms in maintaining appropriate salt concentrations"

I have looked in spotlight, heinneman, excel, jacaranda the macqurie revision guide as well as HSC Online but none of these refer specifically to the importance of enantiostasis or provide enough information to deduce the importance. Most of them simply go rambling on about osmoregulators and osmoconformers without making a clear correlation with enantiostasis...

Thanks - any suggestions would be greatly appreciated

 

[queenie]

isnt its importance... just that theyd die without adapting to the regular changes in their environment?

 

[04er]

that's definitely right, but how would we 'discuss' it?

 

[queenie]

1) define enantiostasis..
2) give an example of it (theres a good example on HSC online- "when salt concentration is changed in the body fluid, this results in the reduced efficiency of an enzyme. To compensate for this change, pH is increased to boost the efficiecy of the enzyme)
3) an estuary is formed when a river meets the sea. In this environment, fresh water draining from the land mixs with saline water from the sea. This results in the change of salinity -> during the daily cycle of tides brining salt water in and out.
Estuarine organisms must be able to respond to the daily changes in salinty - or they die.

Trout, salamon and eels that move from the sea to rivers must also have adaptations to deal with salt and water problems experienced in both freshwater and marine environments.

Specific ways to deal with the daily change in salinity include varying the body's osmotic pressure with that of the environment (osmoconformers). then talk abt Osmoregulators ...
____________________________________________________

having said that, have i 'discussed' it enough for u?

 

[04er]

Originally posted by queenie
1) define enantiostasis..
2) give an example of it (theres a good example on HSC online- "when salt concentration is changed in the body fluid, this results in the reduced efficiency of an enzyme. To compensate for this change, pH is increased to boost the efficiecy of the enzyme)
3) an estuary is formed when a river meets the sea. In this environment, fresh water draining from the land mixs with saline water from the sea. This results in the change of salinity -> during the daily cycle of tides brining salt water in and out.
Estuarine organisms must be able to respond to the daily changes in salinty - or they die.

Trout, salamon and eels that move from the sea to rivers must also have adaptations to deal with salt and water problems experienced in both freshwater and marine environments.

Specific ways to deal with the daily change in salinity include varying the body's osmotic pressure with that of the environment (osmoconformers). then talk abt Osmoregulators ...
____________________________________________________

having said that, have i 'discussed' it enough for u?

WOW thanks queenie - you da legend!!

 

[xiao1985]

definitely define what entiostasis is... the maintainance of relatively stable internal condition, despite varying ambient conditions such as salinity, varying pH level etc....

also provide an eg... noe the eg well... i remembered mangrove, it uses exclusion (lettin water through, but not the salt), secretion (secret excessive salt at the bottom side of leaves) and accumulation (accumulate the remainin unwanted salt in old tree barks/leaves) and discard them to discard the accumulated parts to discard the unwanted salt...

then u can go one discuss the importance of it... normally, living things develop adaptations to the specifc environment, say fresh water fish excrete nitrogeonous waste as ammonia (requires alot of water), because they need to discard huge amount of water to keep their cells from lysing... whereas salt water fish excrete nitrogenous waste as concentrated urea (i believe)... they need to preserve as much water as possible to keep themselves from dehydration (because they are in a hypertonic(? am i right?? cna't remember exactly) condition. if salt level varies(say salinity), then the organism need to cope with both extremities...

 

[queenie]

Originally posted by xiao1985
say fresh water fish excrete nitrogeonous waste as ammonia (requires alot of water), because they need to discard huge amount of water to keep their cells from lysing... whereas salt water fish excrete nitrogenous waste as concentrated urea (i believe)... they need to preserve as much water as possible to keep themselves from dehydration (because they are in a hypertonic(? am i right?? cna't remember exactly) condition.

xiao, true: fresh water fish execrete dilute ammonia.. BUT salt water fish execrete concentrated ammonia.. i dnt think any fish does urea..

and abt the whole hypertonic/hypotonic thing:
- freshwater fish are hypertonic to their surroundings, and
- salt water fish are hypotonic to their surroundings.

 

[xiao1985]

Originally posted by queenie
xiao, true: fresh water fish execrete dilute ammonia.. BUT salt water fish execrete concentrated ammonia.. i dnt think any fish does urea..

ammonia is very toxic due to its alkalinity... it requires alot of water to be excreted due to its high dissulotion rate... many fish (salt water fish) excrete urea rather than ammonia:

) Urea: CO(NH2)2 Ammonia + Carbon dioxide --------> urea + water
Urea is much less toxic than ammonia and can be excreted safely when diluted with a moderate amount of water. Urea is the more common nitrogenous waste in animals with kidneys. These animals include humans, many fish and amphibians.

http://mail.standrews.austin.tx.us/...-80000001/0000D467-80000001/0000426A-70E903AC

 

[t-i-m-m-y]

lol. yet another thread on "enantiostasis"

 

[xiao1985]

Originally posted by t-i-m-m-y
lol. yet another thread on "enantiostasis"

were there threads for enantiostasis before???

 

[queenie]

Originally posted by xiao1985
were there threads for enantiostasis before???

lol about 60, all askin the same question.

xiao, that stuff u posted is not in the hsc syllabus.. according to the hsc textbooks, they all say that fish execrete ammonia, and that salt water execrete concentrated, and freshwater=dilute..

i might b wrong.. any1 else been tought urea for saltwater fish?

 

[04er]

well thanks you guys! I think I have a fair idea of what to do now ^.^

 

[xiao1985]

Originally posted by queenie
xiao, that stuff u posted is not in the hsc syllabus.. according to the hsc textbooks, they all say that fish execrete ammonia, and that salt water execrete concentrated, and freshwater=dilute..

i might b wrong.. any1 else been tought urea for saltwater fish?

yea, i will definitely go into that... but i am almost certain that concentrated ammonia is not feasible for fish to excrete...

 

[Calculon]

Salt water fish excrete concentrated trimethylamine oxide

 

[xiao1985]

true i believe...

i didn't find too much info on fish producing urea... =p unforutnately...

http://www.cephbase.dal.ca/refdb/pdf/6856.pdf

 

[queenie]

Originally posted by Calculon
Salt water fish excrete concentrated trimethylamine oxide

Originally posted by xiao1985
true i believe...

i didn't find too much info on fish producing urea... =p unforutnately...

http://www.cephbase.dal.ca/refdb/pdf/6856.pdf

lol, ok, cal u wernt much help.. so guys, is it ammonia or urea then?

 

[Calculon]

Originally posted by queenie
lol, ok, cal u wernt much help.. so guys, is it ammonia or urea then?

ammonia or urea for what?

 

[babydoll_]

im assuming saltwater fish

 

[Calculon]

Then its neither. Both are too toxic in the concentrations that that are seen in the urine of saltwater fish. The answer is trimethyamine oxide.

 

[queenie]

Originally posted by Calculon
Then its neither. Both are too toxic in the concentrations that that are seen in the urine of saltwater fish. The answer is trimethyamine oxide.

yea, i was referin 2 saltwater fish... dude, that oxide thing isnt in the syllbus, doesnt the syl say fish= ammonia though? cal, does ur textbook actualyl say trimethyamine oxide? or is this from ur chem knowledge?