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very annoyed!!! C6H1206 + 602 -> 6H2O + 6CO2

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Flash
34808.  Sat Nov 26, 2005 8:45 am Reply with quote

See, that's interesting. Is that why 37 is 'normal' for the human body?

 
dotcom
34809.  Sat Nov 26, 2005 8:45 am Reply with quote

Uh..I think I was ill that week :P

 
Flash
34813.  Sat Nov 26, 2005 8:56 am Reply with quote

Had a temperature, I expect.

 
Celebaelin
34814.  Sat Nov 26, 2005 8:58 am Reply with quote

Technically that is a very general statement about metabolism and whilst broadly true for mammals it is not exclusively true.

You know there are bacteria (and other organisms) that live in extreme environments, yes?

Well those bacteria that live in eg consistently very hot environments such as deep sea vents have metabolisms geared to those environments. Their enzymes have evolved to function at temperatures well in excess of 37oC. I'm deliberately not giving details here as if you want to know more you should look it up somewhere.

Be specific when you can. The dreaded 'give examples' part of exam questions.

The general term for organisms that function in hot environments is Thermophiles and the term for those that live in cold environments is psychrophiles. Generally, although this word is actually a new one on me, they are termed extremophiles.

<Edit>In italics 'psychrophiles' isn't easily readable, so I'll write it again. Oh, well it isn't when the p is at the beginning of a line anyway, which it, er, was, honest.</Edit>


Last edited by Celebaelin on Sun Nov 27, 2005 8:52 am; edited 1 time in total

 
dotcom
34820.  Sat Nov 26, 2005 9:12 am Reply with quote

Thanks very much. I'll hit my biology teacher with that one on Tuesday. Shows him for making us watch bloody silly videos about influenza.

 
Celebaelin
34821.  Sat Nov 26, 2005 9:15 am Reply with quote

Flash wrote:
See, that's interesting. Is that why 37 is 'normal' for the human body?


No. The efficiency of enzymes decreases because they are starting to unfold ie denature but that can happen at a range of temperatures for different compositions and structures. The temperature is a product of evolution to provide the most efficient solution for the environment. In a system where the temperature is controlled by homeostatic mechanisms (self-correcting to a set value in the normal state of affairs) the most efficient solution is for the enzymes maximum efficacy and the organisms usual body temperature to co-evolve to the same temperature. This temperature point is itself a play-off between energy expenditure in maintaining a constant body temperature and rate of enzymic function.

This is not a full answer but if you start dealing with all the points with precision it gets...lengthy.

 
Flash
35199.  Sat Nov 26, 2005 7:36 pm Reply with quote

Thanks. Do you think there is a sensible way for Stephen to explain in one sentence why 37 = normal? Other than saying that it's the most efficient temperature, I mean.

 
Caradoc
35260.  Sat Nov 26, 2005 10:56 pm Reply with quote

37 is only "normal" for humans other mammals have different normals as do the other endotherms (birds), exotherms (cold blooded) have different enzymes for different temperatures.

 
Celebaelin
35281.  Sun Nov 27, 2005 4:54 am Reply with quote

Carl wrote:
37 is only "normal" for humans other mammals have different normals as do the other endotherms (birds), exotherms (cold blooded) have different enzymes for different temperatures.


Quite. From

http://www.indiana.edu/~animal/fun/conversions/temperature.html

Quote:
Living organisms have different patterns of body temperature regulation. Body temperature regulation can be described as:

ENDOTHERMIC Body temperature depends primarily on heat produced by metabolism and the dissipation of that heat to the environment (e.g., mammals and birds).

ECTOTHERMIC Body temperature depends primarily on absorption of heat energy from the environment (e.g., reptiles, amphibians, most fish, insects).


POIKILOTHERMIC A pattern of temperature regulation characterized by large variations in body temperature that are due to changing environmental conditions.

HOMEOTHERMIC A pattern of temperature regulation characterized by small variations in body temperature, usually less than plus or minus 2°C.

Below are a few examples of animals with different patterns of temperature regulation, and the typical body temperature for a healthy adult of that species.

Dog Canis familaris 102° F (± 1°) 39° C (± 1°) endotherm, homeotherm
Cat Felis catus 101.5° F (± 1°) 38.5° C (± 1°) endotherm, homeotherm
Pigeon Colomba ssp. 106.6° F 41° C endotherm, homeotherm
Lizard Sceloporus spp. 87.8° - 95° F 31° - 35° C ectotherm, poikilotherm
Fish (Sockeye Salmon) Onchorhynchus nerka 41° - 62.6° F 5° - 17° C ectotherm, poikilotherm
Fish (Rainbow Trout) Salmo gairdneri 53.6° - 64.4° F 12° - 18° C ectotherm, poikilotherm
Rattlesnake Sistrurus miliarius barbouri 59° - 98.6° F 15° - 37° C ectotherm, poikilotherm Grasshopper Melanoplus sanguinipes 101.5° - 108° F 38.6° - 42.2° C ectotherm, poikilotherm


Flash wrote:
Thanks. Do you think there is a sensible way for Stephen to explain in one sentence why 37 = normal? Other than saying that it's the most efficient temperature, I mean.


As regards a single sentence to sum up why a given temperature is normal for a given animal where I have used ‘efficient’ Darwin used ‘fit’ in the evolutionary sense. Darwin was probably right in that efficient doesn’t carry with it the same ‘as read’ implication of a tie in to reproductive success whereas ‘fit’ does.

In fact, as you are doubtless aware, Darwin was not the originator of "Survival of the Fittest"

Quote:
The expression often used by Mr. Herbert Spencer of the Survival of the Fittest is more accurate, and is sometimes equally convenient.

Charles Robert Darwin (1809-1882) The Origin of Species. Chap. iii


Quote:
This survival of the fittest which I have here sought to express in mechanical terms, is that which Mr. Darwin has called “natural selection, or the preservation of favoured races in the struggle for life.
Herbert Spencer (1820-1903): Principles of Biology. Indirect Equilibration.


But if I’d said Spencer you’d most likely have thought ‘What? Who’s he?’

 
JumpingJack
35297.  Sun Nov 27, 2005 6:21 am Reply with quote

Not so, Celebailin.

Spencer's authorship of the phrase was the subject of a question on QI two years ago.

{:o)

But did you know that Herbert Spencer also invented the paperclip?

The device was called Spencer's Binding Pin and was produced on a modified hook and eye machine by a manufacturer called Ackermann in 1845. It did well in its first year, making Spencer £70 in profit, but poor marketing and distribution meant sales soon dried up. Ackermann later shot himself and the invention had entirely disappeared by 1899 when the Norwegian engineer Johann Vaaler filed his patent for the modern paperclip in Germany.

 
Celebaelin
35303.  Sun Nov 27, 2005 6:42 am Reply with quote

It must be selective memory on my part. I remember the bit about the paper clip but not the 'not Spencer either' bit.

Who was it then, 'cos Darwin clearly thought it was Spencer. Not Wallace surely? That would be just too unfair.

 
JumpingJack
35304.  Sun Nov 27, 2005 7:01 am Reply with quote

No, no, you're quite right!

Sorry, you misunderstood me. You wrote:

Quote:
if I’d said Spencer you’d most likely have thought ‘What? Who’s he?’


and I wrote:

Quote:
Not so, Celebailin.

 
Celebaelin
35312.  Sun Nov 27, 2005 7:25 am Reply with quote

Phew!

Cross-err, hang on,

Crossnore (n.)

A temporary moment of confusion in a conversation which, after a pause for both parties to filter through what has been said, turns out to be a point of agreement.

Crossnore is in North Carolina.

 
gerontius grumpus
35331.  Sun Nov 27, 2005 8:31 am Reply with quote

I'm not sure if this is interesting enough but soft centres in chocolates are produced with the help of enzymes.
The soft centre starts as a firm sugar candy containing a small amount of an enzyme which might be called sucrase.
The enzyme slowly converts the sucrose to glucose and fructose which are more soluble than sucrose.
There is sufficient water in the candy to form a syrup with the glucose and fructose.
The reaction is slow enough to allow the candy centre to be covered with chocolate before it turns to syrup.
I have no idea whether the syrup would be suitable for swimming through.

 
Celebaelin
35334.  Sun Nov 27, 2005 8:39 am Reply with quote

Your morning paper is 85% Glucose. Given a Kenwood blender, some cellulase and a suitable filter you could put it on your cornflakes.

 

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