Variation In Heamoglobin 2.3 Flashcards
What is heamoglobin?
A large protein with a quaternary structure. Each polypeptide chain has a haem group which contains iron and gives haemoglobin it’s red colour.
Haemoglobin is said to have a high _________ for oxygen.
Affinity
What is the equation in which oxygen combines haemoglobin to form oxyhaemoglobin?
Hb + 4O2 HbO8
What is meant by the partial pressure of oxygen (pO2)?
It is a measure of the oxygen concentration. The greater the concentration of the dissolved oxygen in the cells, the higher the partial pressure. Haemoglobin’s affinity for oxygen varies depending on the partial pressure of oxygen. The pO will be high in the lungs, but low in respiring tissues.
In terms of partial pressure, when does oxygen load and offload onto haemoglobin?
Oxygen loads onto haemoglobin, when the partial pressure is high (has a high affinity for oxygen) and offloads when the partial pressure is low (has a low affinity for oxygen).
What does a dissociation curve show?
They show how saturated the haemoglobin is with oxygen at any given partial pressure.
Explain the shape of an human dissociation curve.
The graph is s-shaped because the Hb combines with the first O2 molecule, it’s shape alters in a way that makes it easier for other molecules to join too. But as the Hb starts to become more saturated, it gets harder and harder for more oxygen molecules to join.
How does CO2 concentration affect oxygen unloading?
Haemoglobin gives up oxygen more readily at higher partial pressures of CO2. When cells respire they produce CO2 which raises the pCO2, this increases the rate of oxygen unloading, the dissociation curve shifts down. The saturation of blood with oxygen is lower for a given pO2, meaning that more oxygen is being released. (BOHR EFFECT)
How does haemoglobin differ in different organisms?
Organisms that live in an environment with a low concentration of oxygen have haemoglobin with a higher affinity for oxygen. The dissociation curve is to the left of a human dissociation curve.
Organisms that are very active have a high oxygen demand and have haemoglobin with a lower affinity, so their curve is shifted to the right of a human dissociation curve.
What is cellulose made out of?
Two beta glucose molecules.
How do plants store glucose?
As starch
Describe the structure of amylose.
A long, un branched chain of a-glucose. It has a coiled structure, almost like a cylinder which makes it more compact and good for storage.
Describe the structure of amylopectin.
Long branched chain of a-glucose. It’s side branches allow the enzymes that break down the molecules to get at the glycosidic bonds easily. This means that the glucose can be released quickly.
What is the main energy storage material in animals?
Glycogen- another very compact polysaccharide of a-glucose (has almost the same structure as amylopectin)
Why is cellulose so strong?
The cellulose chains are linked together by hydrogen bonds to form strong fibres called microfibrils.
