Lecture 25 done

Lecture 25 done - Lecture 25 Study Questions 1. Describe...

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Lecture 25 Study Questions 1. Describe the different types of cell signaling: endocrine, paracrine, and autocrine. Endocrine signaling: makes up the major class of hormones. Hormones are released from a gland and then travel through the bloodstream to a site with specific receptors anywhere in the body. (up to several meters) Paracrine signaling: When a cell secretes a hormone and the adjacent/closest cells are the receptors. (micrometers) Autocrine: hormone signaling in which a cell produces its own hormones and has receptors to. (micrometers) 2. Where are the cellular receptors for lipophilic and hydrophilic hormones located? Are there exceptions? Hydrophilic hormones have membrane receptors. Lipophilic hormones have intracellular nuclear hormone receptors. Certain lipophilic hormones can also interact with cell-surface receptors (ex: Prostaglandins ) 3. How do steroid hormones influence cellular functions at the transcription level? Steroid hormones (mainly sex hormones) are involved in many functions of early fetal development. Estradiol, progesterone, and testosterone all play very significant roles in the development of specific features, as well as termination of pregnancy. -Heterodimeric nuclear receptors are located exclusively in the nucleus. In the absence of their hormone ligand, they repress transcription when bound to their cognate sites in DNA. They do so by directing histone deacetylation at nearby nuclesomes. In the presence of ligand, lingand binding domains of nuclear receptors also bind mediator, stimulating preinitiation complex assembly. -Homodimeric receptors are found in the cytoplasm in the absence of their
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Lecture 25 done - Lecture 25 Study Questions 1. Describe...

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