Home › AP Biology › Biology › Cell Communication › Order the events of tyrosine kinase receptor act…
Order the events of tyrosine kinase receptor activation after a signaling molecule is released.
AThe ligand binds two nearby receptors, they dimerize, then tyrosine residues are phosphorylated
BThe receptors dimerize first, then the ligand binds, then tyrosine residues are phosphorylated
CTyrosine residues are phosphorylated first, then the receptors dimerize, then the ligand binds
DThe ligand binds one receptor, phosphorylation occurs, then a second receptor dimerizes
Answer & Solution
Correct answer: A. The ligand binds two nearby receptors, they dimerize, then tyrosine residues are phosphorylated
1. Signaling molecules first bind to the extracellular domain of two nearby tyrosine kinase receptors.
2. The two neighboring receptors then bond together, a process called dimerization.
3. Phosphates are then added to tyrosine residues on the intracellular domain of the receptors, a process called phosphorylation.
4. The phosphorylated residues can then transmit the signal to the next messenger in the cytoplasm.
5. The option that starts with dimerization skips the ligand binding step that triggers dimerization in the first place.
6. The option that starts with phosphorylation before dimerization is out of order, since dimerization must occur before the intracellular domains are positioned to phosphorylate each other.
7. The option describing phosphorylation immediately after one receptor binds, before a second receptor dimerizes, contradicts the requirement that two neighboring receptors bond together first.
_Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 9 "Cell Communication", section Types of Receptors_
Related questions
Bacteria use two broad types of autoinducers during quorum sensing that act through differBacterial signaling that depends on the population density of bacteria in the environment Budding yeasts use a secreted signaling molecule to find another haploid yeast cell ready Cyclic AMP signaling is terminated when cAMP is broken down into AMP. Which enzyme carriesSeveral enzymes reverse the modifications made during a signaling cascade to terminate theDuring T-cell development, immature T cells are screened to see whether they bind to the bApoptosis is described as a controlled process that a cell can trigger under certain condiMost growth factors bind to cell-surface receptors linked to tyrosine kinases, called rece