Chapter 9: Cell Communication Flashcards
effective cell signaling requires:
- ligand
- receptor protein
- transduction pathway (produces cellular response)
the ligand is a ______
signaling molecule that binds to a specific receptor protein
the 2 types of ligands are:
- hydrophilic (cannot cross the cell membrane)
- hydrophobic (can cross the cell membrane)
transduction is _________
the conversion of a signal from outside the cell to a form that causes a specific cellular response
the location of the receptor for hydrophobic ligands is _______
intracellular
the location of the receptor for hydrophilic ligands is ________
cell surface
the methods of signaling based on distance from source to receptors are:
- direct contact
- paracrine signaling
- endocrine signaling
- synaptic signaling
- autocrine signaling
direct contact is _______
the direct contact of adjacent plasma membranes for cellular communication
an example of direct contact is ______
a gap junction, which is a junction between adjacent animal cells that allows for the passage of signals between cells
direct contact is important in _______
embryonic development and immune response
paracrine signaling is ________
local signaling where secretion from one cell has an effect on cells in the immediate area
paracrine signaling is _______ and can be destroyed by ________
- short lived
- extracellular enzymes
an example of paracrine signaling is ________
growth factors, which are local regulators in animals that stimulate nearby target cells to grow and divide
endocrine signaling is _________
long distance signaling where hormones are released into the blood stream, which carries them to the target cell
a hormone is _____
a molecule (usually peptide or steroid) that is produced in one part of an organism and triggers a specific reaction in target tissues or organs some distance away
hormones are released from ______
glands
the 2 types of glands are:
- endocrine gland
- exocrine gland
the endocrine gland is a ________
ductless gland that secretes hormones into the extracellular space, where they diffuse into the circulatory system
the exocrine gland is a _______
type of gland that releases its secretion through a duct, such as a digestive gland of a sweat gland
synaptic signaling is ________
the transmission of neurotransmitters from a nerve cell to a synaptic gap (or synaptic clift)
a synaptic gap is ________
the gap between a nerve cell (signaling cell) and a target cell (another nerve cell or muscle cell)
autocrine signaling is when _____
cells send signals to themselves, which will bind the secreting signals to specific receptors on the cells own membrane
the 2 types of receptors are:
- intracellular receptors
- cell surface receptors
intracellular receptors are found in the _______
nucleus or cytoplasm
intracellular receptors are specific for _______
hydrophobic ligands
process of intracellular receptors:
- hormones cross plasma membrane and bind to cytoplasmic receptors
- hormone binding alters receptor conformation so it no longer binds inhibitor
- hormone-receptor complex translocates to nucleus (acts as transcription factor)
- hormone-receptor complex binds to DNA, usually turning on transcription but can also turn it off
- cellular response is change in gene expression
transcription is _______
when dna is used to create mrna, which will exit to the cytoplasm and translate to a protein, bringing about a specific cellular response
an example of an intracellular receptor is _______
the receptor for nitric oxide (NO), which is a ligand released by neurons that innervates the penis, gastrointestinal tract, and cerebral blood vessels
nitric oxide works in the body by _______
crossing the cell membrane of the muscle cells that line blood vessels and binding to the enzyme guanylyl cyclase, which acts as a receptor and catalyzes the synthesis of cGMP which, in the smooth lining, the walls of vertebrate blood vessels cause the relaxation of muscle cells, allowing for blood vessels to expand so more blood can flow in.
some additional examples of an intracellular receptor are _______
receptors for testosterone, cortisol, estrogen, and progesterone. these receptors act as regulators of gene transcription
