Gaseous Exchange

What happens when you breathe in? (tick all that apply)

• diaphragm relaxes and moves up

• diaphragm contracts and flattens

• increases volume in thorax

• reduces volume in thorax

What is tidal volume?

• the volume of air inspired per minute

• The amount of air left in the lungs after expiration

• Volume of air expired per breath at rest

• volume of air inspired per breath at rest

What is the function of chloride shift?

• To balance the pH level in erythrocyte

• To balance the electrochemical charges in erythrocyte

• To balance the carbon dioxide concentration in cells

• To bind with H+ ions forming hydrochloric acid

The diagram shows the oxygen dissociation curves of adult haemoglobin, foetal haemoglobin and myoglobin. Which of the following statements are true of the curves above?

I P is for myoglobin, Q is for foetal hemoglobin and R is for adult hemoglobin

II P is for foetal hemoglobin, Q is for adult hemoglobin and R is for myoglobin

III Based on affinity towards oxygen, P > Q > R

IV Based on ability to dissociate from oxygen at point T, P > Q > R

• I and III

• I and IV

• II and III

• II and IV

Which of the following explains Bohr effect?

• The regulating of constant pH in blood

• The haemoglobin affinity towards carbon dioxide

• The influence of carbon dioxide concentration on the dissociation of oxyhaemoglobin

• The increase in dissociation rate of carbon dioxide due to the influence of ferum ions

The graph is showing an oxygen dissociation curve. Choose the correct statement from the following based on the graph.

• Decrease in the blood pH shifts the graph to the right showing haemoglobin's affinity towards oxygen has reduced.

• Increase in the blood pH shifts the graph to the right showing haemoglobin's affinity towards oxygen has increased.

• Increase in release of oxygen from haemoglobin shifts the graph to the left

• Decrease in the blood pH shifts the graph to the left showing that the affinity of haemoglobin towards oxygen has increased

The largest proportion of CO₂ carried by blood is in the form of –

• Molecular CO₂ dissolved in the plasma

• Bicarbonates (HCO₃^– ) carried within RBCs

• HCO₃^– carried in the plasma

• Molecular CO₂ chemically bound to haemoglobin

The breathing centre initiates ventilation in response to –

• A decrease in air pressure

• A decrease in O₂

• An increase in CO₂

• The rate of gas exchange in the alveoli

What enzyme is required for CO2 to be combined with water to make carbonic acid?

• Carbonic anhydrase

• Carbonase

• Carbonic acid

Which of the following is NOT the structure of haemoglobin?

• Each haemoglobin molecule contains 4 haem group

• Every each haem group in haemoglobin can bind with 4 molecule of oxygen

• Haemoglobin is a quaternary structure

• Each haemoglobin has 2 α-chain and 2 β-chain polypeptide subunits