CIE A Level Biology復習筆記8.2.1 Red Blood Cells, Haemoglobin & Oxygen

Category: A-level課程, 教材筆記, 福利干貨 Date: 2022年8月10日下午3:56

Red Blood Cells, Haemoglobin & Oxygen

Transport of oxygen

The majority of oxygen transported around the body is?bound to the protein haemoglobin in red blood cells
- Red blood cells are also known as?erythrocytes
Each molecule of haemoglobin contains?four haem groups, each able to bond with one molecule of oxygen
- This means that each molecule of haemoglobin can carry four oxygen molecules, or eight oxygen atoms in total

Molecular-structure-of-haemoglobin

Haemoglobin proteins are made up of four subunits, each of which contains a region called a haem group to which oxygen can bind

When oxygen binds to haemoglobin, oxyhaemoglobin is formed

The binding of the first oxygen molecule results in a conformational change in the structure of the haemoglobin molecule, making it easier for each successive oxygen molecule to bind; this is?cooperative binding
The reverse of this process happens when oxygen dissociates in the tissues

Worked Example

There is around 150 g of haemoglobin in 1 dm3?of blood. In a healthy adult at room temperature, 1 g of haemoglobin can combine with 1.3 cm³?of oxygen.

Calculate how much oxygen can be carried in 1 dm3?of blood.

To answer this question, we must look at the information already given to us in the question. You do not need prior knowledge to gain full marks here.

In 1 dm³?of blood, there is 150 g of haemoglobin

1 g of haemoglobin can carry 1.3 cm³?of oxygen

1.3 x 150 = 195

Therefore 150 g of haemoglobin can carry 195 cm³?of oxygen

195 cm³?is the final answer