Chapter 4: Biology of the Cell
ribosomes
Cytoplasmic organelles at which proteins are synthesized. contains RNA and protein
cilia
Hairlike projections that extend from the plasma membrane and are used for locomotion
hypertonic
Having a higher concentration of solute than another solution. and thus a lower concentration of water than the cytosol/ leads to decreased volume and pressure of cell, which can eventually lead to crenation of the cell
channel-mediated diffusion
Movement of small ions through water-filled protein channel specific for one ion type
membrane transport
Movement of substances into and out of the cell.
phosphorylation
addition of a phosphate to a protein
permeable 111
allow passage of substance across membrane/through bilayer
enzymes pg109
attach to either internal or external surface of the cell for catalyzing chemical reactions (biological catalyse)
phospholipid bilayer
basic structure of the plasma membrane, ensures cytosol remains inside the cell and interstitial fluid remains outside
cell surface receptors
bind specific molecules (ligands) (receive)
cytosis - glycogenolysis
breakdown of glycogen to convert it back to glucose (used in ATP/energy production)
glycoproteins 108
carbohydrates exposed to interstitial fluid
uniporter
carrier that transports only 1 substance`
crenation
cell shrinkage
cytosis - endocytosis
cellular uptake of large substances or large amounts of substances (bring into cell)
3 types of receptors that bind ligands to initiate various metabolic effects
channel-linked receptors enzymatic receptors G-protein-coupled receptors (secondary messenger)
negative
charge of the interior of a cell
diffusion - if unopposed
continues until substances reach equilibrium
leak channel 110
continuously open
isotonic
cytosol and solution has same relative concentration of solutes same inside as it is outside
passive process
do not require cellular energy (2 types: diffusion and osmosis) move from more to less moving down concentration gradient
passive processes of membrane transport
do not require energy diffusion osmosis
electrochemical gradient
electrical charge difference across the plasma membrane
integral proteins 108
embedded within and extend across the phospholipid bilayer some are glycoproteins with carbohydrate portion(blue pic)
kinase
enzyme that phophorylates something else acts as an on/off switch
ER - endoplasmic reticulum (ER)
extensive interconnected membrane network that varies in shape and separates fluid within the membraneous structure from the cytosol, typically extends from nuclear envelope to plasma membrane
interstitial fluid
fluid that surrounds cells (also known extracellular fluid)
cell-adhesion proteins pg109
form membrane junctions to perform a number of functions including binding cells to one another (cell-to-cell attachments)
membrane proteins 108
has 2structural type:integral & periphal
mitochondria (power house)
have their own genes from mom gene and does not change double membrane-bound organelles containing a circular strand of DNA "power house" of the cell - synthesizes ATP
centrioles
helps to organize cell division,
aquaporinss
integral protein water channels (water pore)
ER - smooth ER
interconnected membrane lacking ribosomes varies by cell, in certain functions its used to store lipids calcium storage, detoxification
channel - Voltage gated channel
ion channels that open and close due to changes in membrane voltage
proteasomes
its like a recycle, degrade and digest damaged or unneeded proteins but needs Atp large, barrel-shaped protein complexes located in both the cytosol and nucleus
phospholipid
know as balloons with 2 head. They are made up of two fatty acids, which are attached to a glycerol (polar) 'head.'
nucleus
large structure enclosed within a double membrane, contains chromatin, nucleolus, and nucleoplasm that houses DNA, creates ribosomes BOSS/control center or brain of the cell - processing, info
cytosis - exocytosis
large substances or large amounts of substances are secreted from the cell (exit)
Channel- each channel is either
leak or gated channel
cytosis - pseudopodia
like the arms that stick out and brings in cell ( phagocytosis)
glycolipid
lipid within an attached carbohydrate , lipid we add glucose to, group found on the outside of the plasma membrane
general cell functions
maintain integrity and shape of cell obtain nutrients and form chemical building blocks dispose of waste
Free ribosomes
make protein with in the cell
vesicle
membrane-bound (by a smaller phospholipid bilayer) sac filled with materials to be transported
equilibrium
molecules become evenly distributed throughout a given area, this is bad in biology
ligands
molecules that bind specific molecules , bind to macromolecules examples: hormones, neurotransmitters
diffusion
movement of a substance from where it is more concentrated to where it is less concentrated
antiport
moves 2 substances in opposite directions
symport
moves 2 substances in the same direction
cytosis - receptor mediated endocytosis
need a receptor to bring in molecules to cell (receptor is made out of protein) transport inside the cell is mediated with receptors, looks like pinocytosis with the "folding in" but the difference is there are receptors that sit on the membrane
peripheral proteins 109
not embedded within lipid bilayer, instead attached loosely to either the external or internal surfaces of the membrane and are often "anchored" to the exposed parts of an integral protein often enzymes
osmosis
passive movement of water through a selectively permeable membrane membrane prevent passage of most solute Movement of water
carrier-mediated diffusion
passive transport process assisted by a carrier protein to move small, polar molecules (such as simple sugars or amino acids)
simple diffusion 110
passive transport process used when a chemical slips between plasma membrane phospholipids to enter or leave a cell
facilitated diffusion 110
passive transport process using carrier proteins or channel proteins to move a chemical across the plasma membrane diffusion aided by a transport protein, does NOT require energy
Solutes - 2 type of solutes 111
permeable and nonpermeable
Plasma membrane is made out of
phospholipid bilayer with cholesterol
membrane potential
potential energy represented by electrical or voltage difference
hydrostatic pressure
pressure exerted by a fluid on the inside wall of its container
osmotic pressure112
pressure exerted by the movement of water across a semi-permeable membrane due to a difference in solution concentration
non-permeable
prevents passage of substance across membrane/through bilayer
Active transport - the direct source for active transport determines whether the movement is
primary active transport or secondary active transport
centrosome
primary function: organize microtubules within cytoskeleton 2 perpendicular centrioles, proximal to nucleus, surrounded by amorphous protein. made out of 9 tripplets
cytosis - clathrin coated vesicle
protein on the internal surface of the membrane, coats the vesicle that moves into cytosol during receptor-mediated endocytosis (its a protein that helps the receptor mediated endocytosis process)
carrier protein
protein that bonds to a molecule then alters its shape in order to transport the molecule across the plasma membrane ion comes in contact with the transport protein (it is being carried)
identity markers pg109
proteins or glycoproteins that communicate to other cells that they belong to the body
anchoring sites pg109
proteins that secure the cytoskeleton (internal, protein support of a cell) to the plasma membrane
receptor-mediated endocytosis is dependent upon
receptor substrate clathrin
active process
require cell energy moving up concentration gradient vesicular transport
active processes of membrane transport
require energy primary active transport secondary active transport vesicular transport/bulk transport
ER - rough ER
ribosomes attached on cytoplasmic surface, helps make proteins
hemolysis
rupture of red blood cell
lysis
rupture of the cell that occurs if difference in concentration is large enough
cholesterol
scattered within phospholipid bilayer, strengthens the membrane and stabilizes against temperature extremes
Golgi apparatus (shipping)
series of several elongated, flattened sac like membranous structures UPS (modify, package, sort materials) composed of cisternae exhib its polarity Cis-face : enters (proximal to er) trans-face : out the door (distal to ER)
Membrane- Two ways water crosses membrane
slips between molecules of phospholipid BL Through integral protein water chanel - aquaporins
invagination
small area of plasma membrane folds inward into the cytosol to form a pocket, occurs during endocytosis
peroxisomes (they clean)
small, spherical-shaped membrane-bound organelles formed from the ER or through fission that contain oxidative enzymes detoxify Made from the ribosome but donot go to RER, it stays in the cell
channel - Chemical gated channel
sodium wants to go in and potassium wants out
hypotonic
solution has a lower concentration of solutes and higher concentration of water than in the cytosol outside = less concentration than inside the cell leads to increased volume and pressure of cell, which can eventually lead to lysis of the cell
cytosis - pinocytosis
"cellular drinking" cell internalizes droplets of inerstitial fluid that contain dissolved solutes brings in water, ion, make small vesicles
cytosis - phagocytosis
"cellular eating" cell engulfs or captures large particle(s) external to the cell forming membrane extensions (pseudopods) to surrond the particle looks for foreign things and eat them
vesicular transport
(bulk transport) energy input to transport large materials across the plasma membrane by a vesicle examples: endocytosis, exocytosis, phagocytosis, pinocytosis)
secondary active transport
(coupled transport) moves a substance against its concentration gradient using energy provided by the movement of a second substance down its specific concentration gradient through a channel
transport proteins pg109
(entry in and entry out)provide a means of regulating the movement of substances across the plasma membrane (channels, carriers, pumps)
cytoskeleton
(made from microfilaments) provides support, anchors cell, and facilitates movement includes microfilaments, intermediate filaments, and microtubules keep cell shape
membrane transport are organized into
2 major categories : passive process and active process
ATP stands for
Adenosine Triphosphate
Active transport
The movement of particles from an area of low concentration to an area of high concentration that uses energy provided by ATP or a difference in electrical charges across a cell membrane.
tonicity
ability of a solution to change the volume or pressure (or the "tone") of the cell by osmosis
ion pumps 114
active transport proteins that move ions across the membrane
sodium-potassium pumps 114-115
special type of ion pump specifically called an exchange pump because it moves one ion into a cell against its concentration gradient and another type of ion out of the cell against its concentration gradient, "dual pump" two different ions
lysosomes (they destroy)
spherical-shaped membrane-bound organelles formed from Golgi apparatus that contain digestive enzymes "stomach" - digestion - act as the manager - They destroy
diffusion - rate of diffusion depends on
steepness of concentration and temperature
glycolipids
sugar/carbohydrate attached to a fat, located on outer phospholipid region of plasma membrane, helps to form glycocalyx (if present)
glycocalyx
the carbohydrate coat on the cell surface -acts as a nametag so that white blood cells can identify and distinguish normal cells from unwanted cells
potassium is
the slow channel
primary active transport 114
uses energy derived directly from the breakdown of ATP and provides (via phosphorylation) a phosphate group that is added to the transport protein resulting in a change in the protein's shape and subsequent movement of a solute across the membrane examples: ion pumps, sodium-potassium pump
gated channel 110
usually closed, but opens only in response to a stimulus (chemical, light, or voltage change)
resting membrane potential
voltage measured across the plasma membrane of an excitable cell at rest