3 membrane protein types
- peripheral = loosely attached, usually hydrophilic and held in place by H-bonds and electrostatic interaction, disrupted by change in ionic concentration/pH
- integral = usually hydrophobic (interior of plasma membrane is lipid part of phospholipid bilayer); use detergent to destroy membrane and expose
- transmembrane = form of integral, dif domains dif characteristics
function of membrane proteins - 8
- channel - small charged/polar
- recognition - glycoproteins (oligosac attached, ex: major-histocompatability on complex macrophage to distinguish between self and foreign)
- ion channel - gated with voltage, ligand or mechanics (Pressure, Temp, Vibration)
- porins - certain ions/small polar molecules, aquaporins in kidney/roots
- carrier - shape change
- transport - ATP/active or facilitated dif
- adhesion - attach cells to neighboring cells, anchors for internal filaments/tubules (stability)
- receptor - binding sites
cholesterol
rigidity to membrane of ANIMAL cells; sterols do same in plants and HOPANOIDS in prokaryotes; also, none in yeast
glycocalyx
carb coat that covers outer face of cell wall of some bacteria and outerface of PM; consitsts of glycolipids and glocoproteins – adhesive abilities, barrier to infection or markers for cell-cell recognition
nucleus
chromatin = not condensed DNA; chromosome = condensed; 8 histones organize into nucleosome; nucleolous for ribosome synthesis (subunits not put togetehr until cytoplasm); double layer nuclear envelope/membrane with nuclear pores for transport of rRNA, ribosome subunits, dNTPs, proteins (histone, DNA pol); nucleoplasm not cytoplasm
nuclear lamina
dense fibrillar network inside nucleus; mechanical support, DNA rep/cell division/chrom organization regulation; intermediate filaments, membrane associated proteins
nucleoid
irregular shaped region of prokaryote that contains genetic material
cytoplasm
area including cytosol and organelles but not nucleus; cyclosis = streaming movement
cytosol
the gel, not the stuff suspended in it
ribosomes
60S + 40S = 80S (euk); 50S+30S=70S (pro); made of rRNA + proteins
ER, rough
has ribosomes – creates glycoproteins by attaching polysaccharides to polypeptides as they are assembled by ribosomes, continuous with outer membrane of nucleus
ER, smooth
synthesizes lipids/steroid hormones for export; in liver - breakdown of toxic byproducts/drugs/toxins; can store ions (Ca2+ = sarcoplasmic ret)
lysosome
vesicle produced from golgi, digestive enzyme, low pH to function (so if an enzyme escapes, inactive in cyto), apoptotic function
golgi
transport, cis face for incoming vesicle and trans for outgoing secretory vesicles; cisternae = flattened sacs
peroxisomes
breakdown substances H2O2 + RH2 –> R + H2O; use H2O2 to oxidize substances; in liver and kidney; plant - modify products of photorespiration
glyoxysomes
peroxisome in germinating seed to breakdown stored FA to generate energy for growth
microtubules (MT)
tubulin, support/motility for cellular activities; spindle apparatus to guide chromosomes during division; flagella and cilia - 9+2 array (9pairs and 2 singlets in middle) - animals and lower plants (mosses, ferns)
intermediate filaments
support, maintain shape
microfilament (MF)
actin, motility - skeletal muscle, amoeba psuedopid, cleavage furrow
MTOC
MT organizing center; centrioles, basal bodies (base of cilia/flag); 9x3 array; plants have MTOCs but not centrioles because they divide by cell plate, not cleavage furrow
transport vacuole
move materials between organelles
food vaculole
temporary food storage, merge with lysosome to break down
tonoplast
membrane of central vacuole
central vacuole
large, most of plant cell interior; turgor pressue when full - rigidity; store nutrients and carry out lysosomal functions; tonoplast is membrane
storage vacuole
starch, pigments, toxic substances (nicotine)
contractile vacuoles
single celled organisms use these to collect and pump xs h2o out of cell, prevent bursting, active transport; in protista like amoeba/paramecia in hypotonic env
cell walls
in plants, fungi, bacteria, archaea; cellulose, chitin, peptidoglycans, polysaccharides; support, secondary cell wall can develop beneath primary
ECM
in animals. area between adjacent cells; beyond PM & glycocalyx; fibrous structural proteins, adhesion proteins & polysacs; support, bind to adjacent cells **collagen, most common, also integrin and fibronectin
plastids
found in plant cells. chloroplasts (photosyn); leucoplast (starch storage); chromoplasts (carotenoid storage) ** carotenoids serve two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they protect chlorophyll from photodamage.
carotenoids
They serve two key roles in plants and algae: they absorb light energy for use in photosynthesis, and they protect chlorophyll from photodamage. xanthophyll (w/O2) and carotene
mitochondria
make ATP; fatty acid catobolism - beta-oxidation (beta-oxidation is the process by which fatty acid molecules are broken down in the mitochondria to generate acetyl-coA, which enters the citric acid cycle, and NADH and FADH2, which are used by the electron transport chain); circular DNA, own ribosomes, endossymbiotic theory
beta oxidation
eta-oxidation is the process by which fatty acid molecules are broken down in the mitochondria to generate acetyl-coA, which enters the citric acid cycle, and NADH and FADH2, which are used by the electron transport chain
cytoskeleton
MT (cil/flag), MF, intermediate fils; division and motility role in euks
plant in hypotonic soln
isotonic
hypertonic
hypo- vacuole swells, turgor pressure (water rushes in because low solute concentration out vs in)
iso- flaccid plant cells
hyper- plasmolyzed, cytoplasm is pulled away from the cell wall (fungal cells also remain turgid because of cell walls, animal cells burst – cytolysis)
endomembrane system *what does it not include!
- no mitochondria/choloroplasts
- network of organelles and structures either directly or indirectly connected that function in transport of proteins/macromolecules in/out of cell, includes PM, ER, golgi, nuc env, lysosomes, vacuoles, vesicles, endosomes
brownian movement
particles move due to kinetic energy, spreads small suspended molecules throughout cytoplasm; random motion of particles suspended in a fluid (a liquid or a gas) resulting from their collision with the quick atoms or molecules in the gas or liquid
cyclosis/streaming
circular motion of cytoplasm around cell transport molecules
intracellular circulation, 3 components
- brownian movement
- cyclosis/streaming
- ER - provides channel through cytoplasm, PM–>nuc membrane
extracellular circulation
diffusion & circulatory system
anchoring junctions
DESMOSOME- keratin filaments inside attach to adhesion plaques which bind adjacent cells together, providing mechanical stability, and hold structures together (animal cells, found in tissues with mechanical stress - skin epithelium, cervix/uterus)
tight junctions
completely encircles each cell and produces a seal that prevents passage of materials between cells, charactersistic of cells lining digestive tract where materials required to pass through cells into blood; ANIMALS; prevent passage of stuff through intercellular space so that materials must actually enter cells in order to pass through tissues
gap junction
narrow tunnels between animal cells- CONNEXINS- prevent cytoplasms of cells from mixing, but allow passage of ions and small molecules
plasmodesmata
narrow tunnels between plant cells; desmotubule - narrow tube of ER, exchange material through cytoplasms surrounding desmotubule
prokaryote, 5 traits
no nucleus, single circular naked DNA, 50S+30S=70S, cell walls = peptidoglycan (archaea = polysac, plant = cellulose, fungi = chitin); flagella are NOT from MT
bulk flow
collective movement of substances in same direction in response to force or pressure (blodo)
plasmolysis
movement of water out of cell that leads to its collapse (passive transport)
dialysis
diffusion of different solutes across selectively permeable membranes
countercurrent exhcange
diffusion by bulk flow in opposite directions
phagocytosis
active transport, undissolved solid – WBC engulfs and PM wraps around
pinocytosis
active transport of undissolved liquid; PM invaginates
receptor mediated transport
ligand binds receptor, cell engulfs