Downtown Flashcards by Leeroy Jenkins

These detect, amplify, and integrate external signals..

cellular signal transduction cassettes.

How well did you know this?

Not at all

Perfectly

Cellular transduction cassettes are comprised of.. (3)

1) Specific cell surface membrane receptors
2) Effector signaling elements
3) Regulatory proteins

How well did you know this?

Not at all

Perfectly

Six steps of general signals and response..

1) synthesis of signaling molecule (ligand)
2) release of ligand
3) transport of ligand to target cell
4) binding of ligand by specific receptor protein & change in conformation
5) change in cell metabolism, fxn, or development
6) removal of ligand, terminating cellular response
7) degradation of ligand

How well did you know this?

Not at all

Perfectly

Chemical messengers made by endocrine cells and secreted into bloodstream..

Hormones.

How well did you know this?

Not at all

Perfectly

Hormones affect..

gene expression and protein synthesis.

How well did you know this?

Not at all

Perfectly

Types of hormones..

Steroids, Amine (amino acid-derived), Peptide (usually lumped together with polypeptides), Polypeptides

How well did you know this?

Not at all

Perfectly

Steroid hormones that are cholesterol precursors..

Corticosteroids, Androgens, Estrogens.

How well did you know this?

Not at all

Perfectly

Steroid hormones immediately diffuse out of endocrine cells into..

bloodstream.

How well did you know this?

Not at all

Perfectly

Steroid hormones characteristics.. (2)

lipid soluble and have a slower acting/longer half-life than peptide hormones.

How well did you know this?

Not at all

Perfectly

Steroid hormones act as..

intracellular (cytoplasmic) receptors.

Note: located inside target cells.

How well did you know this?

Not at all

Perfectly

Hormones that are tyrosine or tryptophan derived..

Amine hormones.

How well did you know this?

Not at all

Perfectly

These hormones are stored in endocrine cells until secreted..

Amine hormones.

How well did you know this?

Not at all

Perfectly

Receptors for these hormones can be located on the cell surface or intracellular..

Amine hormones.

How well did you know this?

Not at all

Perfectly

These hormones can be stored in endorcrine cell vesicles; they do NOT immediately enter bloodstream..

Polypeptide hormones.

How well did you know this?

Not at all

Perfectly

Polypeptide hormone solubility..

water soluble.

How well did you know this?

Not at all

Perfectly

These hormones do NOT readily pass through cell membrane..

Polypeptide hormones.

How well did you know this?

Not at all

Perfectly

These hormones bind to external receptors, and are known as the “first messengers”..

Polypeptide hormones.

How well did you know this?

Not at all

Perfectly

Intracellular effects of Polypeptide hormones are accomplished through..

low molecular-weight signaling molecules, aka “second messengers”

e.g., cAMP or calcium

How well did you know this?

Not at all

Perfectly

Integral membrane proteins with an extracellular N-terminus..

G-protein coupled receptors.

How well did you know this?

Not at all

Perfectly

G-protein coupled receptors structure..

Seven transmembrane-spanning alpha-helices (Ligand binds to pocket)

How well did you know this?

Not at all

Perfectly

G-protein couple receptors loops..

3 extracellular and intracellular loops.

How well did you know this?

Not at all

Perfectly

This loop recruits G-protein to receptor..

third intracellular loop.

How well did you know this?

Not at all

Perfectly

The C-terminal tail membrane of G-protein coupled receptors is..

intracellular.

How well did you know this?

Not at all

Perfectly

There are no intrinsic catalytic domains associated with..

G-protein coupled receptors.

How well did you know this?

Not at all

Perfectly

G-protein (guanine nucleotide-binding) activates..

adenylyl cylase (converts ATP to cAMP).

Activation of adenlyl cyclase by G-Protein activates..

protein kinases in cytosol. | signal cascade

cAMP is inactivated by..

phosphodiesterase. | turns of cell response

Specficity of the G-protein activity is due to..

alpha-subunit, which contains the GTP-binding site and an intrinsic GTPase activity,

Adenylyl Cyclase is activated by the action of the..

alpha-subunit of the G-protein.

Many Gs aplha-subunits can be stimulated by..

one molecule of bound hormone. Note: amplifies original hormone signal.

Bacterial toxins that target G-proteins..

Cholera toxin & Pertussis toxin ADP-ribosylates Gs alpha-subunit

Increase in cAMP within intestinal epithelial cells..

Cholera toxin.

Enahnces cAMP levels that inhibits neutrophil fxns..

Pertussis toxin (whooping cough).

Increase in cAMP within intestinal epithelial cells leads to phosphorylation of..

Cl-channels and efflux of electrolytes and water (severe diarrhea)

Tyrosine kinase-linked receptors have no..

intrinsic enzymatic activity.

Ligand-triggered protein kinases are..

intrinsic enzymatic activity receptors.

These receptors form dimers upon binding of ligand..

tyrosine kinase-linked receptors & intrinsic enzymatic activity.

Ligand/receptor complex of intrinsic enzymatic activity acts as..

tyrosine kinase. phosphorylates other kinases

Ligand binding changes confirmation of receptor to allow specific ions to flow thru channel..

ion-channel receptor.

bacterial toxin that affects ion-channels..

botulinum toxin. prevents release of acetylcholine neurotransmitter/cleaves proteins involved in docking of NTs

Intracellular [Ca2+].. Extracellular [Ca2+].. Why..

Intracellular - 100 nM Extracellular - 1 nM gradient allows rapid changes in Ca2+ concentration via hormone ligation

Calcium binds to this protein to induce a conformational change..

calmodulin.

Calcium/calmodulin complex binds to these proteins to initiate signal cascades..

kinases.

Second messenger responsible for calcium mobilization..

PIP2

PIP2 is hydrolyzed to 2 second messengers by..

PIP2-specific phospholipase C (PLC)

2 second messengers of derived from PIP2..

IP3 & DAG.

This messenger is water soluble and mobilizes calcium..

IP3.

Anchored in plasma membrane (fatty acid side chains) and activates protein kinase C (PKC)..

DAG.

This molecule can also be hydrolyzed by phopholipases to produce lipid second messengers..

Phosphatidylcholine.

Phosphatidylcholine second messengers..

``` DAG (by PLC) Phosphatidic Acid (PLD) Arachidonic Acid (PLA2) ```

Key inflammatory/pain mediators..

arachidonic acid and prostaglandins.

Precursors of eicosanoids..

prostaglandins, leukotrienes, prostacyclins, thromboxanes

Precursors of eicosanoids signal via..

G-protein coupled receptors.

Arachidonic acid/prostaglandinds functions include..

modulate smooth muscle contraction platelet aggregation gastric acid secretion salt and water balance

Arachidonic acid conversion to prostaglandins involve..

cyclooxygenase isoforms. Note: regulate inflammation, regulate blood flow to organs, control ion transport across membranes, modulate synaptic transmission, induce sleep

constitutive isoform..

COX-1.

Response to inflammatory mediators isoform..

COX-2.

NSAIDS are..

Cyclooxygenase inhibitors. e.g., Aspirin and Ibuprofen; celecoxib - rheumatoid arthritis

Cyclooxygenase inhibitors block..

cyclooxygenase conversion to prostaglandins.

Both cyclooxygenase isoforms are irreversibly inactivated by..

Aspirin.

Arachidonic acid converted into leukotriene by..

lipooxygenases.

Example of a receptor-independent signaling molecule..

Nitric Oxide.

Nitric oxide stimulates..

guanylate cyclase.

Stimulation of guanylate cyclase..

generates cGMP - relaxes blood vessels

Angina symptoms treated with..

glyceryl trinitrate, which is converted to NO.

3 Types of endocytosis..

Pinocytosis, Phagocytosis, Receptor-mediated endocytosis

Nonspecific absorption of extracellular fluid..

Pinocytosis.

Activated by attachment to Pathogen-associated molecular patterns (PAMPs)..

Phagocytosis.

Clathrin coated vesicles (form polyhedral lattice) associated with..

Receptor-mediated endocytosis.

Example of Receptor-mediated endocytosis..

Iron transport via transferring receptor.

Movement of receptors to a different membrane from the one in which it was endocytosed..

Transcytosis.