(4pts) Drugs, medicines, and poisons often work by acting on endogenous proteins. They do this by looking similar to a signal molecule and binding to the endogenous protein. Look up these four examples to fill in this chart. Drug, medicine, or poison Looks similar to this endogenous molecule: Binds to this endogenous protein/receptor: Muscarine Acetylcholine muscarinic receptors Prozac Serotonin serotonin transporter protein Ketamine NMDA NMDA receptor Tamoxifen estrogen estrogen receptor

Drug, medicine, or poison: Muscarine; Looks similar to this endogenous molecule: Acetylcholine; Binds to this endogenous protein/receptor: muscarinic receptors

Drug, medicine, or poison: Tamoxifen; Looks similar to this endogenous molecule: estrogen; Binds to this endogenous protein/receptor: estrogen receptor

Drug, medicine, or poison: Prozac; Looks similar to this endogenous molecule: Serotonin; Binds to this endogenous protein/receptor: serotonin transporter protein

Drug, medicine, or poison: Ketamine; Looks similar to this endogenous molecule: NMDA; Binds to this endogenous protein/receptor: NMDA receptor

Explanation:

Muscarine is a poisonous natural product found in certain mushrooms. It is similar to acetylcholine and competes with acetylcholine at its receptor binding sites.Signs of muscarine poisoning include salivation, lacrimation, vomiting, diarrhea, abdominal pain, bradycardia, etc.

Tamoxifen is a selective estrogen receptor modulator. It is similar to estrogen and acts by inhibiting the effects of estrogen in the breast tissue. It is used to prevent and treat breast cancer in men and women.

Prozac is an antidepressant which belongs to th class known as selective serotonin reuptake inhibitors. It looks similar to serotonin and inhibits its action by competing with serotonin for its binding site. It is used for the treatment of depression disorders.

Ketamine is an NMDA (N-Methyl-D-aspartate) receptor antagonist. NMDA receptor antagonists are a class of drugs that work by inhibiting the action of the NMDA receptor. They are commonly used as anesthetics for animals and humans to induce a state of anesthesia known as dissociative anesthesia.

answer: "circumcision is a common procedure in which the skin covering the tip of the penis is surgically removed."