Slide set 3 Flashcards
Gap junction
direct cytoplasmic transfer between adjacent walls
- forms from the union of membrane- spanning proteins called connexins
- large molecules cannot pass through
Contact-dependent
surface to surface
- includes cell-adhesion molecules (CAMs)
- autocrine and paracrine
endocrine
long distance in the bloodstream
chemicals that diffuse
through extracellular fluid to act on cells close by
connexins
(in gap junctions) membrane-spanning proteins
Cytokines
are synthesized by all nucleated cells ( not glands or specialized cells) but act like hormones, controlling cell development, differentiation and immune responses
-made on demand
GPCR: adenylyl cyclase-cAMP pathway
AC converts ATP to cAMP
cAMP activates protein kinase A, which phosphorylates other molecules and elects a response
GPCR: the Phospholipase C system
PL-C converts membrane phospholipids into DAG and IP3, which goes into cytoplasm and causes Ca2+ release. DAG activates protein kinase C
what initiates the fastest response?
Recptor -Channel ( ions move in or out of cell)
Agonist vs Antagonist?
Agonist also activates the receptor, antagonist blocks activity
microfilaments
smallest cell fibres are microfilaments, they are thin, twisted strands of protein molecules that lie parallel to the long axis of the cell, they slide past each other causing shortening in muscle contraction –> in muscle cells–> actin and myosin are microfilaments!
Intermediate filaments
these are thicker that microfilaments- they form more of a supporting network ( for example a protective outer layer of skin)
microtubules
thickest of cell fibers and they are hollow
there function is to move things around the cell
microvilli are formed from which cytoskeleton fibre?
microfilaments
cilia and flagella are formed by what cytoskeleton fibre?
microtubules ( think that they are bigger than microvilli)
