Front

What is the primary role of haemoglobin in red blood cells?

Back

To transport oxygen

Answer explanation

The primary role of haemoglobin in red blood cells is to transport oxygen from the lungs to the tissues. While it can also carry some carbon dioxide, its main function is oxygen transport, making 'to transport oxygen' the correct choice.

Front

What type of structure does haemoglobin have?

Back

Quaternary

Answer explanation

Haemoglobin has a quaternary structure, consisting of four polypeptide chains (two alpha and two beta) that form a functional protein. This structure is crucial for its ability to bind and transport oxygen effectively.

Front

What is the effect of the first oxygen molecule binding to haemoglobin?

Back

It makes the binding of further oxygen molecules easier

Answer explanation

The binding of the first oxygen molecule to haemoglobin induces a conformational change, making it easier for additional oxygen molecules to bind. This cooperative binding enhances oxygen uptake in the lungs.

Front

What is the oxyhaemoglobin dissociation curve used to illustrate?

Back

The relationship between oxygen concentration and haemoglobin saturation

Answer explanation

The oxyhaemoglobin dissociation curve illustrates the relationship between oxygen concentration and haemoglobin saturation, showing how readily haemoglobin binds to oxygen at different oxygen levels.

Front

What is the Bohr effect?

Back

The effect of carbon dioxide concentration on the dissociation of oxyhaemoglobin

Answer explanation

The Bohr effect describes how increased carbon dioxide concentration lowers the pH, promoting the release of oxygen from hemoglobin. This enhances oxygen delivery to tissues that need it most, making the correct choice about carbon dioxide's role.

Front

How does an increase in carbon dioxide concentration affect haemoglobin's affinity for oxygen?

Back

Decreases affinity

Answer explanation

An increase in carbon dioxide concentration decreases haemoglobin's affinity for oxygen, a phenomenon known as the Bohr effect. This allows for more oxygen to be released in tissues where it is needed most.

Front

What happens to haemoglobin when it releases oxygen?

Back

It changes shape

Answer explanation

When haemoglobin releases oxygen, it undergoes a conformational change, altering its shape. This change facilitates the binding of carbon dioxide, enhancing its ability to transport gases in the blood.

Front

Which of the following best describes cooperative binding in haemoglobin?

Back

Binding of one oxygen molecule increases the affinity for others

Answer explanation

Cooperative binding in hemoglobin means that when one oxygen molecule binds, it increases the affinity of the remaining binding sites for additional oxygen molecules, facilitating more efficient oxygen uptake.

Front

What is the main component of red blood cells that carries oxygen?

Back

Haemoglobin

Answer explanation

The main component of red blood cells that carries oxygen is haemoglobin. It binds to oxygen in the lungs and transports it to tissues throughout the body, making it essential for respiration.

Front

What is the primary factor that causes haemoglobin to release oxygen in tissues?

Back

Low pH

Answer explanation

Haemoglobin releases oxygen in tissues primarily due to low pH, which indicates higher carbon dioxide levels and increased acidity. This shift promotes oxygen unloading, enhancing oxygen delivery where it's needed most.