OXYGEN DISSOCIATION CURVE

With reference to the graph, which of the areas represent the percentage saturation in a resting muscle tissue?

• A and C

• A alone

• B and C

• B alone

Using the graph, what does graph A represent?

• graph of fetal haemoglobin

• graph of sickle celled haemoglobin

• graph of adult haemoglobin

• graph of denatured haemoglobin

Which statement truly represents the difference between the two curves?

• Curve A represents an haemoglobin that has higher affinity for oxygen at all partial pressures of oxygen

• Curve A represents a curve that has higher affinity for haemobloby at only at low partial pressures of oxygen

• Curve A represents haemoglobin that will readily release oxygen at all partial pressures

• Curve A represents haemoglobin that will not readily bind to oxygen even at high partial pressure of oxygen

At which range of partial pressure will both haemoglobin have the same percentage saturation?

• 90mmHg - 100mmHg

• 60mmHg - 100mmHg

• 60mmHg - 100 mmHg

• 80mmHg - 100mmHg

Using the graph, which of the following is true about myoglobin?

• it is proteinous in nature

• it does not readily release its oxygen until partial pressure of oxygen starts falling below 40mmHg

• it only releases it's oxygen when haemoglobin has released all its oxygen

• compared to adult haemoglobin, it releases more oxygen when partial pressure reduces from 60mmHg to 30mmHg

Under which range of partial pressure decrease will myoglobin release more oxygen than adult hemoglobin?

• decrease from 15mmHg to 5mmHg

• decrease from 40mmHg to 20mmHg

• decrease from 80mmHg to 20mmHg

• decrease from 100mmHg to 20mmHg

At partial pressure of 20mmHg, ………………………

• Adult haemoglobin has a higher affinity for oxygen than myoglobin

• Adult haemoglobin is less saturated with oxygen compared to myoglobin

• Adult haemoglobin is completely deoxygenated while myoglobin is not

• Adult haemoglobin still has capacity to release a large amount of oxygen compared to myoglobin

Which of the following is not the characteristics of haemoglobin?

• Has high affinity towards oxygen

• Easily releases oxygen when the partial pressure of oxygen is low

• Shows allosteric cooperatively binding characteristic

• Carbon dioxide can also bind to haem group of haemoglobin

This best describes positive cooperativity of hemoglobin

• As 1 O₂ binds to a heme group, it causes a sudden shift of polarity, attracting more O₂

• As 1 O₂ binds to a heme group, a conformational change occurs, making it more likely for additional O₂ to bind

• As 1 O₂ binds to a heme group, hemoglobin becomes slightly less hydrophilic

• As 1 O₂ binds to a globin group, the binding site of O₂ within the molecule becomes more exposed

An oxygen dissociation curve will shift to the right in what condition describe below.

• Increased partial pressure of oxygen

• Decreased partial pressure of oxygen

• Increased partial pressure of carbon dioxide

• Decreased partial pressure of carbon dioxide