Biological Systems MCAT Practice Exam 2025 – The Comprehensive All-in-One Guide for Exam Success!

The main component of the extracellular matrix (ECM) in connective tissue is collagen. Collagen is a fibrous protein that provides structural support and strength to tissues. It constitutes the majority of the ECM in many types of connective tissue, forming a network that helps resist tension and facilitates the tissue’s overall integrity and resilience.

Collagen fibers are found in various connective tissues, including tendons, ligaments, cartilage, and bone, making them crucial for their mechanical properties and durability. The presence of collagen also plays a role in cellular communication and the regulation of cellular behaviors, contributing to tissue repair and development.

While elastin is also an important component of the ECM, providing elasticity and resilience to tissues, it is not as predominant as collagen. Adipose tissue primarily serves as energy storage and insulation, rather than being a part of the ECM. Ground substance, which consists of glycoproteins, proteoglycans, and water, is present in the ECM and helps to support cells and fibers within connective tissues but is not a singular component like collagen. Thus, collagen stands out as the main structural element in the extracellular matrix of connective tissue.