Haemoglobin

Question 1

What is the main function of haemoglobin?
A) Transport of oxygen and carbon dioxide
B) Production of ATP
C) Blood clotting
D) Digestion of proteins

Answer 1

A

Question 2

Haemoglobin is a tetramer composed of how many subunits?
A) 2
B) 3
C) 4
D) 5

Answer 2

C

Question 2

What happens when Fe²⁺ is oxidized to Fe³⁺ in haemoglobin?
A) It enhances oxygen binding
B) It forms methaemoglobin, which cannot bind oxygen
C) It increases oxygen transport efficiency
D) It strengthens the heme-heme interaction

Answer 2

B

Question 2

What is the prosthetic group in haemoglobin?
A) Globin
B) Ferritin
C) Heme
D) Albumin

Answer 2

C

Question 2

What is the oxidation state of iron in functional haemoglobin?
A) Fe³⁺
B) Fe²⁺
C) Fe⁴⁺
D) Fe⁰

Answer 2

B

Question 3

Which enzyme reduces methaemoglobin back to functional haemoglobin?
A) Carbonic anhydrase
B) Catalase
C) NADH-cytochrome b5 reductase
D) Superoxide dismutase

Answer 3

C

Question 4

Which of the following correctly describes adult haemoglobin (HbA)?
A) 2 alpha and 2 beta chains
B) 2 alpha and 2 gamma chains
C) 2 beta and 2 gamma chains
D) 2 delta and 2 gamma chains

Answer 4

A

Question 5

Which type of haemoglobin is predominant in a fetus?
A) HbA
B) HbS
C) HbF
D) HbC

Answer 5

C

Question 6

Why does fetal haemoglobin (HbF) have a higher oxygen affinity than adult haemoglobin (HbA)?
A) It binds oxygen irreversibly
B) It does not bind to 2,3-BPG effectively
C) It has only two subunits
D) It has more iron atoms per molecule

Answer 6

B

Question 7

What is the Bohr effect?
A) Increased oxygen affinity of haemoglobin in acidic conditions
B) Decreased oxygen affinity of haemoglobin in acidic conditions
C) Increased haemoglobin production in response to hypoxia
D) Binding of CO₂ to haemoglobin

Answer 7

B

Question 8

Which of the following factors shifts the oxygen-haemoglobin dissociation curve to the right?
A) Decreased CO₂ levels
B) Increased temperature
C) Alkalosis
D) Decreased 2,3-BPG

Answer 8

B

Question 9

What is the normal shape of the oxygen-haemoglobin dissociation curve?
A) Hyperbolic
B) Linear
C) Sigmoidal
D) Exponential

Answer 9

C

Question 10

What is the primary function of 2,3-BPG in red blood cells?
A) Enhancing oxygen binding to haemoglobin
B) Reducing haemoglobin affinity for oxygen
C) Converting CO₂ into bicarbonate
D) Maintaining haemoglobin in its oxidized form

Answer 10

B

Question 11

What happens when the oxygen-haemoglobin dissociation curve shifts to the left?
A) Increased oxygen unloading
B) Decreased oxygen affinity
C) Increased oxygen affinity
D) Increased CO₂ binding

Answer 11

C

Question 12

16. How is most carbon dioxide transported in the blood?
    A) Dissolved in plasma
    B) Bound to haemoglobin as carbaminohaemoglobin
    C) As bicarbonate ions
    D) Bound to albumin

Answer 12

C

Question 13

What is the chloride shift in CO₂ transport?
A) Movement of Cl⁻ ions out of red blood cells
B) Exchange of Cl⁻ for bicarbonate (HCO₃⁻) across the red blood cell membrane
C) Conversion of CO₂ into carbonic acid
D) Uptake of bicarbonate into the kidney tubules

Answer 13

B

Question 14

Which gas has the highest binding affinity for haemoglobin?
A) Oxygen
B) Carbon dioxide
C) Carbon monoxide
D) Nitrogen

Answer 14

C

Question 15

What is the effect of carbon monoxide on haemoglobin?
A) Increases oxygen binding
B) Prevents oxygen release to tissues
C) Shifts the oxygen dissociation curve to the right
D) Enhances CO₂ transport

Answer 15

B

Question 16

What is the treatment for carbon monoxide poisoning?
A) High-dose aspirin
B) Hyperbaric oxygen therapy
C) Blood transfusion
D) Vitamin C supplementation

Answer 16

B

Question 17

A patient with cyanosis is found to have high methaemoglobin levels. What is the likely cause?
A) Carbon monoxide poisoning
B) Exposure to oxidizing drugs
C) Dehydration
D) Increased 2,3-BPG

Answer 17

B

Question 18

A climber at high altitude experiences shortness of breath. What adaptation occurs in red blood cells?
A) Increased 2,3-BPG production
B) Decreased haemoglobin levels
C) Increased methaemoglobin formation
D) Increased pH in the blood

Answer 18

A

Question 19

A patient with severe sepsis has a shift of the oxygen-haemoglobin dissociation curve to the right. What is the primary reason?
A) Decreased CO₂
B) Increased temperature
C) Increased oxygen saturation
D) Decreased haemoglobin levels

Answer 19

B

Question 20

A neonate with jaundice has an increased breakdown of which type of haemoglobin?
A) HbA
B) HbS
C) HbF
D) HbC

Answer 20

C

Question 21

Which of the following statements about heme is correct?
A) Heme is a protein structure attached to globin
B) Heme contains Fe³⁺, which binds oxygen
C) Heme is a complex of protoporphyrin and Fe²⁺
D) Heme does not directly interact with oxygen molecules

Answer 21

C

Question 22

Which statement describes the Bohr effect? A) Haemoglobin releases more oxygen at lower pH and higher CO₂ concentrations B) Haemoglobin binds more oxygen when CO₂ levels are high C) The binding of one oxygen molecule increases the binding of others D) Oxygen binding affinity remains constant regardless of pH changes

Answer 22

A

Question 23

What type of protein is haemoglobin classified as? A) Fibrous protein B) Globular protein C) Enzyme D) Structural protein

Answer 23

B

Question 24

Which form of haemoglobin has the highest affinity for oxygen? A) Oxyhaemoglobin B) Deoxyhaemoglobin C) Carbaminohaemoglobin D) Methaemoglobin

Answer 24

A

Question 25

What is the primary reason for the sigmoidal shape of the oxygen-haemoglobin dissociation curve? A) Bohr effect B) Cooperative binding of oxygen C) Presence of 2,3-BPG D) Chloride shift

Answer 25

B

Question 26

What happens to haemoglobin’s oxygen affinity when pH decreases? A) Increases B) Decreases C) Remains unchanged D) First increases, then decreases

Answer 26

B

Question 27

What is the effect of 2,3-BPG on haemoglobin? A) Increases oxygen affinity B) Decreases oxygen affinity C) Converts CO₂ into bicarbonate D) Reduces CO₂ binding

Answer 27

B

Question 28

What is the fate of haemoglobin after red blood cells are broken down? A) Converted into bilirubin B) Excreted in urine unchanged C) Stored as glycogen D) Used to form DNA

Answer 28

A

Question 29

What happens to haemoglobin affinity for oxygen at high altitudes? A) Increases B) Decreases C) Remains unchanged D) Becomes unpredictable

Answer 29

B

Question 30

What happens when carbon monoxide binds to haemoglobin? A) Enhances oxygen release B) Prevents oxygen release C) Increases blood pH D) Decreases CO₂ binding

Answer 30

B

Question 31

A climber at high altitude experiences fatigue and dizziness. What is the physiological response to compensate? A) Decreased erythropoietin B) Increased 2,3-BPG production C) Decreased red blood cell count D) Increased oxygen affinity

Answer 31

B

Question 32

What lab test is commonly used to measure haemoglobin levels? A) ESR B) Complete blood count (CBC) C) PT/INR D) Liver function test

Answer 32

B

Question 33

A patient with carbon monoxide poisoning has a normal PaO₂ but severe hypoxia. Why? A) Increased oxygen unloading B) Reduced oxygen delivery due to CO binding C) Increased haemoglobin production D) Increased red blood cell count

Answer 33

B

Question 34

A blood gas analysis shows a right-shifted oxygen dissociation curve. What could be the cause? A) Hypothermia B) Increased CO₂ C) Decreased 2,3-BPG D) Alkalosis

Answer 34

B

Question 35

A patient with chronic lung disease is found to have polycythaemia. What is the likely cause? A) Low erythropoietin levels B) Chronic hypoxia C) Decreased 2,3-BPG D) High carbon monoxide exposure

Answer 35

B

Question 36

What is the primary function of haemoglobin in acid-base balance? A) Oxygen transport B) CO₂ buffering C) ATP synthesis D) Immune function

Answer 36

B

Question 37

What is the primary reason why fetal haemoglobin (HbF) has a higher oxygen affinity than adult haemoglobin (HbA)? A) HbF has fewer globin chains B) HbF does not bind 2,3-BPG effectively C) HbF has a different iron oxidation state D) HbF has a larger molecular weight

Answer 37

B

Question 38

Which of the following haemoglobin variants is protective against malaria? A) HbS B) HbA C) HbC D) HbF

Answer 38

A

Question 39

What is the role of haptoglobin in haemoglobin metabolism? A) It binds free haemoglobin in plasma to prevent kidney damage B) It transports oxygen in red blood cells C) It enhances haemoglobin degradation D) It regulates erythropoietin production

Answer 39

A