Question

A scientist notices that when she adds a small, water-soluble molecule to a dish of cells, the cells turn off transcription of a gene. She hypothesizes that the ligand she added binds to a(n) ______ receptor. Intracellular Hormone Enzyme-linked Gated ion channel-linked

Answer 1

Enzyme-linked

Step-by-step explanation:

The cell surface receptors that have intracellular domains associated with enzymes are called enzyme-linked receptors. The added molecule was water-soluble and cannot pass through the membrane to bind to intracellular receptors. Binding of the added molecule to the enzyme-linked receptor led to the activation of associated enzymes to generate the response (down-regulation of expression of the target gene).

Examples of enzyme-linked receptors include tyrosine kinase receptors. Binding of the signaling molecule to these receptors triggers phosphorylation of the intracellular domain which in turn transmits the signal to the cytoplasmic messenger.