Advanced Placement (AP) Biology Practice Exam

What are the three main types of membrane receptors?

1. G-protein linked, ion channels, nuclear receptors

2. Tyrosine kinases, ion channels, nuclear receptors

3. G-protein linked, tyrosine kinases, ion channels

4. G-protein linked, tyrosine phosphatases, ion channels

The correct answer is: G-protein linked, tyrosine kinases, ion channels

Membrane receptors play crucial roles in cellular communication and signaling. The three main types of membrane receptors are G-protein coupled receptors, tyrosine kinase receptors, and ion channel receptors. G-protein coupled receptors (GPCRs) are a large family of cell surface receptors that detect molecules outside the cell and activate internal signal transduction pathways, which ultimately result in cellular responses. They are involved in various physiological processes such as sensory perception and immune responses. Tyrosine kinase receptors are another important type of membrane receptor. When ligands bind to these receptors, they undergo dimerization and autophosphorylation on tyrosine residues. This phosphorylation activates a cascade of downstream signaling pathways that regulate cell growth, differentiation, and metabolism. Ion channel receptors allow specific ions to flow through the plasma membrane in response to the binding of a ligand. The opening or closing of these channels can rapidly change the membrane potential and is critical for processes such as nerve impulse transmission and muscle contraction. Each of these receptor types plays a distinct and vital role in cellular signaling, facilitating the communication between cells and their environment. This understanding underscores why the correct choice identifies G-protein linked receptors, tyrosine kinases, and ion channels as the three main types of membrane