Question

Compare and contrast cell surface receptors and intracellular receptors by selecting the most accurate description of their similarities and differences.

a) Both types of receptors initiate the same signaling pathway.
b) Cell surface receptors are hydrophobic, while intracellular receptors are hydrophilic.
c) Cell surface receptors bind to lipid-soluble hormones, while intracellular receptors bind to water-soluble hormones.
d) Cell surface receptors interact with hormones outside the cell, while intracellular receptors interact with hormones inside the cell.

Answer 1

d) Cell surface receptors interact with hormones outside the cell, while intracellular receptors interact with hormones inside the cell. They differ in their location, ligand specificity, and mechanism of signal transduction.

Step-by-step explanation:

d) Cell surface receptors interact with hormones outside the cell, while intracellular receptors interact with hormones inside the cell. Cell surface receptors are typically integral membrane proteins that span the cell membrane, allowing them to interact with signaling molecules, such as hormones, outside the cell. This interaction initiates cascades of events within the cell, often involving second messenger systems. In contrast, intracellular receptors are located within the cell, usually in the cytoplasm or nucleus. They primarily bind to lipophilic or hydrophobic hormones, such as steroid hormones. Once bound, these receptors undergo conformational changes and translocate into the nucleus, where they directly affect gene expression, modulating cellular responses. This distinction in location and hormone specificity highlights the functional differences between cell surface and intracellular receptors in cellular signaling pathways.