Phospholipids differ in.txt
Card Set Information
Phospholipids differ in.txt
principles of life
Phospholipids differ in
chain length, degree of saturation, and kinds of polar groups present
Two important factors in membrane fluidity
lipid composition, temp
lack hydrophobic groups and are not embedded in the bilayer
peripheral membrane proteins
are partly embedded in the phospholipid bilayer
integral membrane proteins
extends through the bilayer on both sides and may have different function in its external and transmembrane domains
plasma membrane carbs are located on the ____ membrane. they can serve as ___.
outer; recognition sites
A carb bonded to a lipid
a carb bonded to a protein
thsi type of transport does NOT require metabolic energy
this type of transport DOES require metabolic energy
types of passive transport
simple diffusion and facilitated diffusion
diffusion through the phospholipid bilayer
diffusion through channel proteins r aided by carrier proteins
speed of diffusion depends on these 3 factors
diameter, temp, concentration gradient.
____ molecules do not pass through the bilayer. they are not soluble
polar. they are hydrophilic and instead stay in the aqueous environment near the membrane
diffusion of water across membranes
during _________ water passes through special membrane channels
this kind of solution has a higher solute concentration
this kind of solutions have equal solute concentrations
these kinds of solution has a lower concentration
the internal pressure against the cell wall. preventing water from entering as it builds up
two ways of facilitated diffusion
channel proteins and carrier proteins
this is a type of channel protein- most are gated. and can be opened or closed to ion passage
this opens when a stimulus caused the channel to change shape
a chemical signal
a ____ gated channel responds to its ligand
a ______ gated chanenel opens or closes in response to a change in the voltage across the membrane
water crosses membranes at faster rate than ______ diffusion
water may ______ with ions such as Na+ as they pass through ion channels
the faciliated diffusion sysetm can become _____ when all of the carrier molecules are bound and the rate of diffusion reaches its max
______ transport requires the input of energy to move substances against their concentration gradient.
______ transport is used to overcome concentration imbalances that are maintained by proteins in the membrane
the energy source for active transport
active transport is _____ and moves a substance against its concentration gradient.
a substance moves in the durection of the ______
types of active transport
primary and secondary
this kind of acive transport involves hydrolysis of atp for energy
primary active transport
this kind of active transport used the energy from an ion concentration gradient, or an electrical gradient
this is an important membrane protein that pumps sodium OUT of the cell and K in
one molecule of ATP moves ___ K and ____ na ions
______ active transport used energy that is regained
secondary acive transport may begin with ______ of a few ions, or may involve ______ that transports both a substance and ions
diffusion; carrier protein
macromolecules are too big or too charged to pass through membranes, instead, they pass through
To take up or secrete macromolecules, cells must use
endocytosis or exocytosis.
3 types of endocytocis (brings into cell)
phagocytosis, pinocytosis, receptor-mediated endycytosis.
during _____, the membrane invaginates the molecules and forms a vesicle that separates fom the membrane
during ____, part of the membrane engulfs a large particle of a cell
during _____, (cellular drinking), small vessicles form, bring in fluids/dissolved substances
receptor mediated endocytosis depend on _____ to bind specific molecules (their ligands)
receptors are important membrane proteins locaed in
cytoplasmic surace is coated by another protein
when receptors bind to their ligands, the coated pit ____ and forms a _________
invaginates; coated vesicle
The clarhrin stabilizes the vesicle as it carries the _____ into the cyttoplasm
Once inside, the vesicle loses its _____ and the substance is digested
this process moves the materials out of the cell in vesicles
in exocytosis, the vesicle membrane fuses with the ___________ and the contents are released into the cellular environment
these kinds of signals affect the same cell that released them
these kinds of signals diffuse to and affect NEARBY cells
these kinds of signals travel to distant cells
only cells with thte necessary receptors can respond to a signal. the ___ cell must be able to sense it and respond to it
a signal transduction pathway involves a ___, a ____ , and a _____.
signal, receptor, and response
during _______ regulation, a signal molecule (ligand), fits into a three dimensional site on the receptor protein, causes it to change shape, and produces either a short or long term response.
_______ receptors have ligands, such as estrogen, that are small or non polar and can diffuse across the membrane
______ receptors have large or polar ligands, such as insulin, that CANNOT diffuse and must bind toa transmembrane receptor at an extracellular site.
_____ ____ ______, also known as GATED ___ _____ , change their three dimensional shape when a ligand bonds.
ion channel receptors, gated ion channels
___________ receptors change their shape when a ligand binds
protein kinase catalyze the pholowing reaction:
ATP + PROTEIN = ADP + PHOSPHORYLATED PROTEIN
ligands binding to a ______ expose a site than can bind to a membrane protein (a _______ protein).
g protein-linked receptors; g protein
the ______ protein is partially inserted in the lipid bilayer and parially exposed on the cytoplasmic surface
3 subunits of g proteins
receptor, GDP AND GTP (USED FOR ENERGY TRANSFER), and an effector protein to cause an effect in the cell.
The g protein-linked receptor changes a GDP nucletide bound to the g protein for a higher enrgy
signaling can initiate a ______ of protein interactions; the signal can then be ____ and_____ to cause different responses
cascade; amplified; distributed
a _____ messenger is an intermediary between the receptor and the cascade of responses.
in fight or flight response, epinephrine activates the liver enzyme _______ __________.
______ enzyme can be activated by the membrane bound epinephrine in broken cells as long as parts are present.
the molecule that delivers the messege from the 'first messenger', epinephrine to the enzyme.
cyclic AMP (cAMP)
in protein kinase pathway, ______ binds to its receptor and activates a G protein
cAMP is produced and activates _________-it phosphorylates two other enzimes with opposite effects ____ & ______.
Protein kinase A; inhibition; activation
During _____, protein kinase A inactivates glycogen synthase through phosphorylation and prevents gluclose storage
During ____ phosphorylase kinase is activated when phosphorylated and is part of a cascade that results in the liberation of glucose molecules.
Signal trasductione ends when
the cell responds
2 ways cells can alter the balance of enzymes
synthesis or breakdown of enzyme & activation or inhibition of enzymes by other molecules
3 ways cell function changes in response to environmental signals
opening of ion channels, alterations and gene expression, alteration of enzyme activities.
What effect does caffeine have on the brain?
similar structure to adenosine, so it bind's to adenosine's receptors (which cause drowsiness) and inhibits thems so alertness occurs