Chapter 9 Flashcards
what are the 2 types of signaling in muticellular organisms?
- intercellular signaling
2. intracellular signaling
what is intercellular signaling?
between cells (adjacent or far apart)
what is intracellular signaling? give an example
within a cell
ex. turning an enzyme on or off
what are chemical signals called and how do they work?
ligands; they bind to another molecule
what two cells are involved in chemical signaling?
- signaling cell
2. target cell
what does the signaling cell do
produces ligand
what does the target cell do?
binds to the receptor
what are the four types of chemical signaling?
- autocrine
- singaling across gap junctions
- paracrine
- endocrine
what is autocrine signaling?
a cell signaling itself
what is signaling across gap junctions?
it allows passage of molecules between cells
what is paracrine signaling?
when the target cell is near the signaling cell, but not connected to it, so ligands are released locally
what is endocrine signaling?
long distance, endocrine glands in the body send ligands through the bloodstream to target cells with specific receptors for each hormone
what type of signaling is neurotransmission?
paracrine
what are the two cells associated with neurotransmission?
presynaptic cell and postsynaptic cell
which is the signaling cell in neurotransmission?
presnyaptic cell
what is the target cell in neurotransmission?
postsynaptic cell
what is the synaptic gap, how big is it, and why?
the space between the pre and postsynaptic cells, has to be very small because neurons need to travel very quickly
how does the endocrine system work?
communicating organs send ligands to target cells with receptors for certain hormones
what are the 4 type of signal receptors?
- internal receptor proteins
- surface receptor proteins
- ion channel receptor proteins
- G-linked and enzyme-linked
what do internal receptor proteins do?
respond to ligands to turn genes on or off
what do surface receptor proteins do and what two types are there?
are integral and peripheral, receive and bind to ligands, change conformation, and trigger a reaction
what do ion channel receptor proteins do?
regulate movement across membranes
what do G-linked and enzyme-linked receptors do?
special functions
what are the four responses to a chemical signal?
- gene expression
- regulation of cellular metabolism
- regulation of cell growth
- cell death (apoptosis)
what is the region of DNA that houses the instructions to make proteins?
gene
how do chemical signals regulate cellular metabolism?
metabolic pathways (like cellular respiration) can be regulated by turning enzymes on/off
what is an example of a ligand in cellular respiration?
ATP, it bonds to phosphofructokinase and stops cellular respiration
how do chemical signals regulate cell growth? give an example
cells don’t constantly grow, they have to stop once they are grown enough, so ligand signals stop growth
ex. brain cells stop dividing once you reach adulthood
how do chemical signals regulate apoptosis?
cells have defined lifespans, and ligands send a signal telling them when it’s time to go, and the cell ceases function
