Explain the adaptive advantage of haemoglobin (1 Viewer)

[neo o]

I'm getting conflicting stuff from my two text books on this point, so could someone please clarify whats going on for me?

Textbook 1 -

The adaptive advantage of haemoglobin is that its shape changes slightly each time it binds to an oxygen molecule. The attachment of the first molecule makes it easier for the second molecule to bind, and so on. Due to this, a small rise in oxygen pressure increases the percentage binding/saturation by a large amount and therefore haemoglobin can remain at near optimal levels in high altitudes despite the low oxygen concentration of the air.

Textbook 2 -

Basically alot of random crap like not having a nucleus and therefore having room for more oxygen (I don't see how that's adaptive but w/e ), holding four oxygen molecules and therefore being more efficient, having the oxygen stored inside a red blood cell instead of being dissolved in the blood plasma etc etc.

Cheers!

 

[malkin86]

Oxygen is very important for cell respiration, so an adaptation that can give more oxygen = an adaptive advantage.

Our teacher used to go on about how she used to have to teach about the people with high blood counts and short bodies up on the mountains, but that's not in the syllabus anymore..

 

[acmilan]

Basically the amount of oxygen that can be transported with haemoglobin in the form of oxyhaemoglobin is much more than can be transported if oxygen was simply dissolved in the plasma. Since oxygen is so essential to cells for respiration, the more oxygen, the better.

 

[xiao1985]

a combination of all infact...

text book 1 is correct... the bindin to one oxygen molecule does fasten the rate to bind other oxygen molecules... whereas, that's less obvious i think... more obvious advantages:

oxygen is only loosely bonded to iron complex in the haemologin... so that it can readily give up the oxygen whenever needed...

each haemoglobin contains 4 heam units... making it capable of carrying up to 4 oxygen molecules...

it is included in the red blood cells, so that it does not upset the osmotic balance in the body

red blood cell do not contain nucleus, hence is capable of carryin more heamoglobin in each red blood cell...

 

[neo o]

Thanks for that guys

 

[mei_ling03]

everything that xiao said plus the fact that organisms with haemoglobin can adapt and survive to a wider ranger of environments where oxygen levels vary. e.g. at high altitudes. that's the adaptive advantage and all the facts about haeomoglobin and the red blood cell is the explain part

 

[lukebennett]

you could also say that in 100ml of normal healthy blood HB can carry 20ml of Oxygen

 

[pink_and_blue]

Haemoglobin and oxygen levels

The city of La Paz in Bolivia is a city with one of the highest altitudes in the world. Some poeple who visit La Paz find it very difficult to breathe especially if they exercise. Newcomers to La Paz are recommended to move slowly at first to acclimatise themselves to the altitude. Yet people who are born, grow up and live in this Andean city do not experience these problems.

This relates to the process of obtaining oxygen from the air at high altitudes and to the molecule that binds the oxygen - haemoglobin.

Haemoglobin is a miltipurpose molecule. It plays a role in transporting some carbon dioxide and it buffers the hydrogen ions produced from carbonic acid.

STRUCTURE OF HAEMOGLOBIN
The red pigment haemoglobin is the main component of our red blood cells. It is composed of four units of a protein called globin. Towards the centre of each globin is a haem unit. Haem is a ring structure with iron in the centre. it is the iron that binds the oxygen, in a weak interaction that can be easily broken. A red blood cell is packed with haemoglobin molecules. The cell has no nucleus so more haemoglobin molecules can be included. They symbol for haemoglobin is Hb.

THE FUNCTION OF HAEMOGLOBIN IN TRANSPORTING OXYGEN
The functions of haemoglobin include:
- transport of oxygen to body cells from the lungs
- transport of some carbon dioxide from body cells to the lungs.
- buffering of the hydrogen ions that are produced from the ionisation of carbonic acid (carbonic acid is made when some carbon dioxide reacts with water). They hydrogen ions are attached to amino acid groups on the large haemoglobin molecule.

The major role of haemoglobin is the transport of oxygen. Oxygen is not very soluble in water and most of it is carried by haemoglobin in the red blood cells. The interaction of iron ions with oxygen bind oxygen to haemoglobin, forming oxyhaemoglobin. This occurs when the pressure (concentration) of oxygen is very high, for example in the lungs. Each haemoglobin molecule can bind four oxygen molecules (one molecule per haem). The opposite occurs at the body cells, where oxygen pressure (concentration) is low. This is a reversible reaction that can be summarised as follows:
Hb + O2 = HbO2
Haemoglobin + oxygen = oxyhaemoglobin

There are approximately 280 million haemoglobin molecules in each red blood cell. If each haemoglobin can bind four oxygen molecules than each red blood cell can thoretically carry 4(280 000 000) or 1,120,000,000 molecules of oxygen.

SATURATION OF HAEMOGLOBIN WITH OXYGEN
Haemoglobin saturation is the percentage of haem units containing bound oxygen. For example, if all the haemoglobin molecules are fully loaded with oxygen, there is 100% saturation. If all the haemoglobin molecules have, on average, two molecules of oxygen then there is 50% saturation.

The saturation of haemoglobin with oxygen is dependant on the PO2 (pressure of oxygen, whcih is directly related to the concentration of oxygen) in the evironment of the haemoglobin. At the lungs PO2 is high so oxygen diffuses into the blood and binds to the haemoglobin. At the body cells the opposite occurs. The PO2 is low so O2 is released from the haemoglobin and diffuses into the body cells.

The relationshop between PO2 and haemoglobin saturation provides a mechanism for regulating the amount of oxygen delivered to tissues. When tissues are relatively inactive the local PO2 is approximately 40mm Hg. Not much oxygen is released. When the tissues become more active they use more oxygen, so the PO2 in the tissue decreases to 15-20 mm Hg. More oxygen is releaased from haemoglobin. So the release of oxygen depends on how much oxygen is being used, Under normal resiting conditions haemoglobin returning to the lungs in the veins will still be 75% saturated with oxygen (although it may be called deoxyhaemoglobin). Haemoglobin fully saturated with oxygen is called oxyhaemoglobin.

 

[wangurflapper88]

Re: Haemoglobin and oxygen levels

:burn:

The city of La Paz in Bolivia is a city with one of the highest altitudes in the world. Some poeple who visit La Paz find it very difficult to breathe especially if they exercise. Newcomers to La Paz are recommended to move slowly at first to acclimatise themselves to the altitude. Yet people who are born, grow up and live in this Andean city do not experience these problems.

This relates to the process of obtaining oxygen from the air at high altitudes and to the molecule that binds the oxygen - haemoglobin.

Haemoglobin is a miltipurpose molecule. It plays a role in transporting some carbon dioxide and it buffers the hydrogen ions produced from carbonic acid.

STRUCTURE OF HAEMOGLOBIN
The red pigment haemoglobin is the main component of our red blood cells. It is composed of four units of a protein called globin. Towards the centre of each globin is a haem unit. Haem is a ring structure with iron in the centre. it is the iron that binds the oxygen, in a weak interaction that can be easily broken. A red blood cell is packed with haemoglobin molecules. The cell has no nucleus so more haemoglobin molecules can be included. They symbol for haemoglobin is Hb.

THE FUNCTION OF HAEMOGLOBIN IN TRANSPORTING OXYGEN
The functions of haemoglobin include:
- transport of oxygen to body cells from the lungs
- transport of some carbon dioxide from body cells to the lungs.
- buffering of the hydrogen ions that are produced from the ionisation of carbonic acid (carbonic acid is made when some carbon dioxide reacts with water). They hydrogen ions are attached to amino acid groups on the large haemoglobin molecule.

The major role of haemoglobin is the transport of oxygen. Oxygen is not very soluble in water and most of it is carried by haemoglobin in the red blood cells. The interaction of iron ions with oxygen bind oxygen to haemoglobin, forming oxyhaemoglobin. This occurs when the pressure (concentration) of oxygen is very high, for example in the lungs. Each haemoglobin molecule can bind four oxygen molecules (one molecule per haem). The opposite occurs at the body cells, where oxygen pressure (concentration) is low. This is a reversible reaction that can be summarised as follows:
Hb + O2 = HbO2
Haemoglobin + oxygen = oxyhaemoglobin

There are approximately 280 million haemoglobin molecules in each red blood cell. If each haemoglobin can bind four oxygen molecules than each red blood cell can thoretically carry 4(280 000 000) or 1,120,000,000 molecules of oxygen.

SATURATION OF HAEMOGLOBIN WITH OXYGEN
Haemoglobin saturation is the percentage of haem units containing bound oxygen. For example, if all the haemoglobin molecules are fully loaded with oxygen, there is 100% saturation. If all the haemoglobin molecules have, on average, two molecules of oxygen then there is 50% saturation.

The saturation of haemoglobin with oxygen is dependant on the PO2 (pressure of oxygen, whcih is directly related to the concentration of oxygen) in the evironment of the haemoglobin. At the lungs PO2 is high so oxygen diffuses into the blood and binds to the haemoglobin. At the body cells the opposite occurs. The PO2 is low so O2 is released from the haemoglobin and diffuses into the body cells.

The relationshop between PO2 and haemoglobin saturation provides a mechanism for regulating the amount of oxygen delivered to tissues. When tissues are relatively inactive the local PO2 is approximately 40mm Hg. Not much oxygen is released. When the tissues become more active they use more oxygen, so the PO2 in the tissue decreases to 15-20 mm Hg. More oxygen is releaased from haemoglobin. So the release of oxygen depends on how much oxygen is being used, Under normal resiting conditions haemoglobin returning to the lungs in the veins will still be 75% saturated with oxygen (although it may be called deoxyhaemoglobin). Haemoglobin fully saturated with oxygen is called oxyhaemoglobin.

 

[beentherdunthat]

Whoa, loved this dot point it's so easy.

· Explain the adaptive advantage of haemoglobin:
– Adaptive Advantage:
§ If blood carried oxygen without haemoglobin, the oxygen would have to be dissolved directly into the plasma (into water).
§ Oxygen is not very soluble in water
§ If oxygen was carried only by being dissolved in blood plasma, 100 ml of water would only be able to carry 0.2 ml of oxygen
§ The presence of haemoglobin increases the oxygen carrying capacity of blood by 100 times. 100 ml of blood actually carries 20 ml of oxygen.
§ Dissolved only ----> 0.2 ml O2 / 100 ml blood
§ Haemoglobin ----> 20 ml O2 / 100 ml blood
§ This ability of blood to carry large quantities of oxygen gives mammals a considerable survival advantage
§ Mammalian cells need a lot of energy and therefore must have a continual supply of OXYGEN for RESPIRATION
§ The extra energy allows mammals to be active, as well as grow large.

From A.S.I's Notes. Check the bio resources section for a link on them. They are really good. (If you don't find them, pm me for the link)

 

[Buiboi]

it also binds loosley with Oxygen molecules allowing it to pick up and drop off oxygen easily.

\the fact that it consists of 4 haems, each consisting of an oxygen molecule makes it 4x as efficient in oxygen transportation for cellular respiration, considering that energy is not reusable and requires a consistnet supply of oxygen

 

[ssglain]

But the fact that RBCs have no nucleus and hence is capable of housing more haemoglobin is beside the point, right? It appears to me that this is an adaptive advantage of RBCs rather than that of haemoglobin. I've always stayed away from writing that in exams, but is it an acceptable answer?

 

[Buiboi]

^^^
yeah you can, i forgot to mention that one, my teacher gave me that as an adaptive adv under that dotpoint so it should be valid, even though it seems like an adaptive adv of RBC's, i guess it relates to haemoglobin in taht it can be transported efficiently throughout the body, hence the oxygen too?? So perhaps an adv in terms of its movement/transport?

 

[beentherdunthat]

^^^ Yep. That is an adaptive advantage. :uhhuh:

 

[chocomania]

thanks for that, really helped
much clearer now


to infinity and beyond....
muahahahahha

 

[misbahf]

Whether it helps or not, when carbon dioxide enters the blood as a waste product from repiration, it reacts with hydrogen to form acid.

In that brief moment, blood is made slightly more acidic and denatures the haemoglobin molecule, releasing the oxygen and binding to the carbon dioxide.

And this goes with the entire thing that mammals can respire at a greater rate than animals without heamoglobin, hence survive in more diverse environemnts, grow bigger, be active all the time etc.

 

[ashy=princess]

wow! all that information combined leads to one hell of an answer! thank you everyone!