The exposed cap is then removed by a decapping enzyme (DCP1/DCP2), unprotected mRNA susceptible to degradation by XRN1, a 5′→3′ exoribonuclease. Removal of the poly(A) tail also makes mRNAs susceptible to degradation by cytoplasmic exosomes containing 3′→5′ exonucleases.

TLS Online TPP Program

#Id: 1245

#Unit 7. System Physiology – Animal

Somatotropes—human growth hormone promotes growth of the entire body by affecting protein formation, cell multiplication, and cell differentiation.

TLS Online TPP Program

#Id: 1246

#Unit 7. System Physiology – Animal

Somatostatin (somatotropin release–inhibiting hormone) –hypothalamus Inhibit growth hormone secretion.

TLS Online TPP Program

#Id: 1247

#Unit 7. System Physiology – Animal

Somatostatin binds membrane receptor, which is coupled to Galpha i protein.

TLS Online TPP Program

#Id: 1248

#Unit 7. System Physiology – Animal

Before puberty, growth hormone excess causes gigantism

TLS Online TPP Program

#Id: 1249

#Unit 7. System Physiology – Animal

After puberty, growth hormone excess causes acromegaly

TLS Online TPP Program

#Id: 1250

#Unit 7. System Physiology – Animal

Posterior pituitary secretes neuropeptides, ADH and oxytocin