Signalling Flashcards
what are the three steps of cell communication?
Reception, transduction, and response
Describe the one direct cell pathway of communication
gap junctions: they are passages between cells, they are responsible for providing quick messages straight through the cytoplasm.
describe the main characteristics of steroid lignds
- derived from cholesterol
- lipophilic, so they cant be stored in vesicles
- since they are lipophlic, they can diffuse across the membrane and bind to intracellular receptors
- they act as gene transcription factors
3 types of steroids
mineralocorticoids, glucocorticoids, and sex hormones
what are eicosanoids derrived from?
phospholipids
what path do the eicosanoids follow?
paracrine (one cell to another)
what are eicosanoids biggest role?
they signal pain and inflammation
what are pain eicosanoids called
prostaglandins
what enzyme converts phosopholipids into eicosanoids?
phospholipase II
what are characteristics of protein signals?
- most of them are enzymes
2. they are hydrophilic, so they can be stored in vesicles
How can protein enzymes be regulated in the cell
an inactive peptide comes along and binds to the enzymes sequence, rendering the enzyme inactive until needed. Once the enzyme is needed, the inactive part drops off, and the enzyme then folds and goes about its business
What are 3 characteristics of amine messengers, and what is an example?
- the are recognized by an amine group
- they are synthesized from amino acid
- they are hydrophilic, so they can be stored
what are the only amine ligands that arent hydrophilic
thyroid hormones
What two paths are purines used by
paracrine and neuronal
What are gases usually in the cell?
waste
what four modes of transport are used by the gases
direct, paracrine, neuronal, and endocrine
What kind of ligand must a intracellular receptor have?
A small or a lipophillic one
What often occurs when a lignad binds with its intracellular receptor which is position near or on the nuclear membrane?
the ligand and receptor form a unit that turns into a transcription factor
what are 2 characteristics of lipid rafts?
- sphingolipids and cholesterol are in high amounts, to keep everything sticking together
- the phospholipids are much longer to accomodate the large proteins
what is the difference between autocrine and paracrine?
Autocrine: the cell secretes a ligand that binds to a receptor on itself
Paracrine: ligand secreted by a cell, and the ligand goes to another cell
what is endocrine signaling?
lignad passes through transportaion system and binds to a specific cell
what is an example of an exocrine gland?
a sweat gland
which group of ligands can act as transcription factors?
steroids
what are two examples of well known purines
caffeine and uric acid
what are the three types of transmembrane protein receptors?
Ligand gated ion channels
receptor-enzyme, and
g-protein coupled receptors
what is a major role a intracellular receptor bound to a lignad?
it can become a transcription factor
What are the four classes of receptors?
Ligand gated ion channels, enzyme receptor, G-protein coupled receptors, and intracellular receptors
What is a product of guanylate cyclase?
converts GTP into cGMP, bro
