Colloidal particles always carry an electric charge. The nature of this charge is the same on all the particles in a given colloidal solution and may be either positive or negative. 

Negatively charged sol $\Rightarrow \mathrm{CdS}$

Positively charged sol $\Rightarrow {\mathrm{Fe}}_2{\mathrm{O}}_3.{\mathrm{xH}}_2\mathrm{O}$

Macromolecular colloids are individual particles that are large enough to be considered colloids (diameter around 100 nm). These particles are made up of chemicals with a high molecular weight.

Macromolecular colloid $\Rightarrow$Starch

Gel $\Rightarrow$ Cheese