3.3.4.1 Mass Transport in Animals (UNFINISHED)

Define mass transport

Bulk movement of gases or liquids in one direction

What do mass transport systems help do

Maintain diffusion gradients and quickly move substances

Define haemoglobin

A globular protein which is an oxygen-carrying pigment found in red blood cells

Name two ways red blood cells maximise diffusion

Bioconcave for a high SA:Vol ratio, no nucleus for more oxygen storage

Describe how Hb has a quaternary structure

It is made up of four polypeptide chains

Define global proteins

Chains or subunits making up Hb, each with a prosthetic haem group

How are global subunits arranged

With disulphide bonds and a hydrophobic core

What features does Hb’s structure aid

The 3D structure and solubility

Describe how a prosthetic haem can bind to oxygen

The Iron ion in it can combine with oxygen to form oxyhemoglobin

How many oxygen molecules can a Hb carry

4

How many oxygen atoms can a Hb carry

8

Describe the function of Hb

Binding oxygen and transporting it from the lungs to the tissue, as it is not soluble

Give the other name for red blood cells

Erthrocytes

Define partial pressure

Pressure exerted by oxygen (concentration)

When is Hb saturated

When all its binding sites are filled

What does the oxygen disassociation curve show

The rate at which oxygen associated with Hb at partial pressures

Define affinity

How easily Hb binds and dissociates with oxygen

What does a high affinity mean for Hb

It can bind easily and dissociate slowly

What does a low affinity mean for Hb

It binds slowly and dissociates easily