cell communication Flashcards
purpose of communication
- growth and division control
- regulate development of cells to tissues
- coordinate metabolic activities
direct cell communication types
- gap junctions = cell junctions between cytoplasm by jooining membranes
- cell surface molecule interaction = receptors on a cell physically attach to surface proteins of another
local communication types
- autocrine - hromomne binds to same cell, recpetors on same cell or cytoplasm recieves
- paracrine - release hormones for nearby cells (includes neurotransmission)
- endocrine - distant, blood flow
what is a hormone and characteristics
molecule produced in one tissue and causes change in another
- secreted into body fluids
- bind to receptors (specific)
- initiate changes
what are receptors
- proteins that binds to ligand (homeormes etc)
- can be on cell wall or nucleus
types of receptors
- transmembrane = span cell mebrane with ntracellular and extracellular parts - recpetor on extra, cause intra effect
- intracellular = recpetors in cytoplasm, typically lgland activated transcription factors whcih change shape and interact with DNA to transcribe
types of transmembrane receptors
- enzyme linked = enzyme activated by binding of ligland
- ion channel-linked = binding of ligland opens or closes a channel
- g protein coupled receptors = membrane bound receptor is coupled to a guanine nucleotide binding protein
what are nerve cells
- excitable cells that respond to external stimuli through a rapid and reversible alterantion to electrical potential of cell mebrane
how is external stimuli interpreted
- converted to electrical signals
- transmitted from peripheral to central
- generates electrical signal trasmitted to effector cells via peripheral nerves
how does a nerve impulse work
- local depolarisation causes permeability
- acto=ion potential moves down axon
- once at end of neuron, propagation of an impulse by electrical currents between active and inactive area of nerve
how are nerve impulses passed
- acetylcholine released from synaptic vessel and diffuses across synaptic gap
- bnds to specific recpetor on post-synaptic membrane
neurotransmission in muscle contraction
- acetylcholchine binds to muscle cell receptor and causes depolarization.
- cause release of Ca2+ in muscle cell
- myosin interacts with actin = contracts
how is muscular ATp generated
- creatine phosphate
- catbolism (lactic acid fementation)
modes of molecule transport across a membrane
- passive diffusion
- import/export via receptors
- nuclear transport
- microtubule
- anterograde transport (ER to golgi)
- retrograde (golgi to ER)
how do prokaryotes move
- flagella coposed of filament, hook and basal body
- requires ATP to move it
- cilia - extension of plasma membrane
flagella vs cilia
cilia = small
many cells
cell stationary - move fluids around it instead
flagella =
long
one cell
entire cell movements