A Level Biology Practice Exam 2025 – 400 Free Practice Questions to Pass the Exam

Antibodies are specialized proteins produced by the immune system in response to the presence of pathogens such as bacteria and viruses. Their primary role is to bind specifically to these pathogens. By clumping the pathogens together, antibodies facilitate easier recognition and elimination by other components of the immune system, such as phagocytes. This process is also known as agglutination, which enhances the ability of the immune system to clear the infections efficiently.

The other options do not relate to the function of antibodies. For example, repairing cell membranes is a role performed by various cellular components and enzymes, while producing cellular energy is primarily handled by mitochondria and metabolic processes. Transporting nutrients is managed by transport proteins and other mechanisms within the cell rather than by antibodies. Thus, the role of antibodies in clumping pathogens supports their crucial function in immune defense.