haemoglobin

Question 1

what is a quaternary structure?

Answer 1

two or more polypeptide chains

Question 2

why is haemoglobin used to transport oxygen in the blood?

Answer 2

because oxygen solubility in water is very low

Question 3

how any polypeptide chains does haemoglobin have?

Answer 3

4

Question 4

what is the prosthetic group in haemoglobin ?

Answer 4

haem group (Fe2+)

Question 5

what is another name for red blood cells?

Answer 5

erythrocytes

Question 6

how many oxygen molecules does one haem group bind to?

Answer 6

1

Question 7

what is the maximum number of oxygen molecules a haemoglobin can bind to?

Answer 7

4, 1 per haem group

Question 8

how MUST haemoglobin do in order to be efficient at transporting oxygen?

Answer 8

readily associate with oxygen (in the lungs) and readily dissociate oxygen at respiring tissues

Question 9

does haemoglobin always bind to 4 oxygen molecules?

Answer 9

no, it may also bind to 1,2 or 3 oxygen molecules

Question 10

what is percentage saturation?

Answer 10

amount of oxygen bound to haemoglobin

Question 11

give the formula of percentage saturation

Answer 11

oxygenated haemoglobin/maximum saturation x100

Question 12

what is cooperative bonding?

Answer 12

when the first oxygen molecule binds to haemoglobin it alters the tertiary structure of the haemoglobin making it easier for the 2nd and 3rd oxygen to bind

Question 13

what is partial pressure of oxygen?

Answer 13

the proportion of oxygen in a mixture of gases or solution

Question 14

what is the shape of the oxygen dissociation curve?

Answer 14

sigmoidal

Question 15

what is meant by the term affinity?

Answer 15

chemical attraction

Question 16

where is the pO2 high at where is it low?

Answer 16

high at the lungs, low at the respiring tissues

Question 17

what happens at the lungs?

Answer 17

• high pO2
• haemoglobin has a higher affinity for oxygen
• haemoglobin becomes almost fully saturated (98%)

Question 18

what happens at respiring tissues?

Answer 18

• low pO2
• hamoglobin has a lower affinity for oxygen
• oxyhaemoglobin begins to break down

Question 19

what is the dissociated oxygen used for?

Answer 19

aerobic respiration

Question 20

what is the effect of increased respiration rate on oxygen dissociation?

Answer 20

• aerobic respiration-reduces O2 in tissue fluid
• reduces pO2
• oxygenated blood unloads more oxygen due to lower affinity

Question 21

what is Bohr shift?

Answer 21

• if pO2 saturation increases, saturation oh Hb decreases
• Hb has a lower affinity for oxygen
• dissociation curve shifts to the right

Question 22

what is the effect of CO2 on oxygen dissociation?

Answer 22

• CO2 dissolves in the blood and makes it more acidic
• lowers the pH
• alters the tertiary structure of Hb
  lower affinity to O2

Question 23

what is the relationship between surface area to volume ratio of mammals and their oxygen dissociation curves?

Answer 23

• smaller mammals have a greater S.A : V ratio so more heat is lost per unit body mass
• smaller mammals have greater rate of respiration
• oxygen required for aerobic respiration
• Hb releases more oxygen-so has a lower affinity

Question 24

what causes variations in Hb affinity?

Answer 24

mutations

Question 25

foetal haemoglobin and haemoglobin in organisms living at high altitudes/bottom of lakes has a ________ affinity for oxygen

Answer 25

higher
curve shifts to the right
becomes fully saturated at lower pO2

Question 26

which organisms have Hb which has a curve shifted to the right?

Answer 26

very active animals or small animals that lose het through a large S.A :V ratio

Question 27

why do organisms with a high metabolic rate have a curve shifted to the right?

Answer 27

• Hb has a lower affinity foe O2
• so dissociates readily so more O2 is available for aerobic respiration

Question 28

what is haemoglobin?

Answer 28

a protein

Question 29

how many haemoglobin molecules does one red blood cell contain?

Answer 29

approx. 300 million