Test 3 - Bartling Flashcards
(90 cards)
Cellular signal transduction cassettes detect, amplify, and integrate external signals comprised of:
- Specific cell surface membrane receptors
- Effector signaling elements
- Regulatory proteins
Six steps of signaling
- Synthesis of the signaling molecule (ligand)
- Release of the signaling molecule (ligand)
- Transport of signaling molecule to target cell
- Binding of the ligand by a specific receptor protein and CHANGE in conformation
- Change in cellular metabolism, function, or development - cellular response
- Removal of ligand, terminating cellular response
- Degradation of ligand
Define hormones
Chemical messengers made by endocrine cells and secreted into the blood
T/F: Hormones affect gene expression and protein synthesis
True
Autocrine hormones
Act on the same cell that they were secreted from
Paracrine hormones
Act on other cells
Types of hormones
- Steroids
- Amine (amino acid derived)
- Peptide (lumped with polypeptides)
- Polypeptides
3 Cholesterol Precursors:
- Corticosteroids
- Androgens
- Estrogens
What do steroids immediately do?
Diffuse out of endocrine cells into the blood
Are steroid hormones lipid soluble?
Yes. They can cross cell membranes.
Where are the steroid hormone receptors?
Intracellular (cytoplasmic) receptors are located inside target cells
Steroid hormones have a _____ (longer/slower) acting, _____ (longer/slower) half-life than peptide hormones.
Slower Acting
Longer half-life
How do steroid hormones lead to signal cascades?
- Hormone diffuses into cell
- Activated receptor hormone complex alters gene expression
- New mRNA directs synthesis of certain proteins to ribosomes
- New proteins alter cell activity
What are Amine hormones derived from?
Tryptophan and Tyrosine
Where are amine hormones stored until they’re secreted?
In endocrine cells
Where are amine hormone receptors located?
Can be located on the cell surface or intracellular
Do polypeptide hormones immediately enter the blood?
No. They can be stored in endocrine cell vesicles
Polypeptide hormones are ___ soluble
Water
Do polypeptide hormones readily pass through the cell membrane?
No
What are polypeptide hormones also called?
First messengers - they bind to external receptors
Intracellular effects are mediated by
Second messengers
Second messengers are ____ (low/high) weight signaling molecules such as:
Low molecular weight
Cyclic adenosine monophosphate (cAMP) or Calcium
G-protein coupled receptors are ___ ___ proteins
Integral membrane proteins (extracellular N-terminus)
G-protein coupled receptors have ___ (#) transmembrane-spanning alpha-helices (ligand binds to pocket)
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