Step 1: Understanding the question.
In the presence of high salt concentration, both proteins and polysaccharides can bind to silica columns due to their charge interactions and affinity for the surface. This technique is commonly used in chromatography to separate biological molecules.
Step 2: Analyzing the options.
(1) Proteins: Proteins can bind to silica under specific conditions, but this is not the full answer as polysaccharides also bind.
(2) Polysaccharides: Polysaccharides also bind to silica but not exclusively; proteins play a role too.
(3) Both proteins and polysaccharides: Correct — Both proteins and polysaccharides bind to silica under high salt conditions in chromatography processes.
(4) Plasmid DNA: Plasmid DNA typically does not bind to silica unless specific conditions are applied, such as in DNA purification protocols.
Step 3: Conclusion.
The correct answer is (3) Both proteins and polysaccharides, as both components interact with silica under high salt conditions.