Chapter 6: A Tour of The Cell
-Prokaryote: no organelles /enclosed
membranes, very small, always single-cell,
circular DNA, can pick up plasmids, has size
70s ribosomes, 1chr
-Granum: stack of thylakoids
-Stroma: fluid around thy., contains
DNA/rRNA/enzymes
-Mitochondria: cellular respiration aka ATP
synthesis
-Cristae: inner membrane foldings
-Mitochondrial Matrix: contains DNA and
rRNA
-Peroxisomes: 1 memb., contains enzymes that
remove H+ & create H2O2
~break fatty acids, detoxifies in liver
~grows using proteins & lipids from cyto. & ER,
-Eukaryote: DNA contained in membranebound nucleus, single/multi-celled, 80s
ribosome, membrane bound organelles, big,
linear DNA, many chr.
-Cytoskeleton: network of fibers thru
cytoplasm, mechanical structure/shape,
in/external movement in cell
-Microtubules: hollow, 25nm diameter, made of
tubulin (A, B), motility (cilia/flagella),
organelle/ chr. movement, cell shape
-Middle Lamella: thin layer btwn cells, sticky
p.sacchar. (pectin), glues adj. cells together
-Secondary Cell Wall: multi laminated layers,
hard/sturdy
~some plants just harden 1st wall, other secrete a 2nd
-Extracellular Matrix: made of glycoproteins
(collagen!), carbs,
~collagen: most common glycoprotein, embedded in
proteo.
~proteoglycans: network, small core protein+carb
chains (95% carb),
~Fibronectin:glycoprot. that connects ECM to cells
~integrins: cell-surf. receptor proteins that connect to
ECM (thru fibronectin)
-Tight Junctions: watertight, cells are pressed
against e/other (skin) bound w/proteins
-Desmosomes: sheets, int.filaments (keratin)
anchor desmosomes in muscles
-Gap Junctions: cytoplasmic channel btwn cells,
similar to a plant’s plasmodesmota
Chapter 7: Membrane Structure &
Function
-Limitations on cell size: SA is needed for
diffusion & smaller cells have a higher SA:V
ratio so theyre small or thin/narrow
-Microfilaments: 7 nm dia., 2 str. actin, cell
shape/change, muscle contraction, cell div.
-Permeability: memb. is selective to prevent
harmful subs. from entering, can allow only
certain molecules
-Phospholipids: P head+2 fatty acids, philic
heads on outside, phobic tails inside (aka
amphipathic)
-Fluid Mosaic Model:
~microvilli add SA w/o V
-Cell Compartmentalization: organelles allow
for specialization (specific environ. Inside,
acids, storage, etc)
-Nucleus: dbl membrane bound, contains DNA,
controls all cell activities
-Nuclear Envelope: dbl membrane w/ pores that
regulate exit/entry
-Nuclear Lamina: netlike array of protein
filaments that support the envelope
-Chromatin: complex of DNA & proteins that
make up chr.
-Nucleolus: rRNA synthesis
-Ribosome: protein synthesis
-Chromosome: structures carrying genetic info
-Endomembrane System: an interconnectedness
btwn organelles thru vesicles
-Vesicles: membrane sacs
-Golgi Apparatus: “pancakes”, products of ER
are stored here
~extensive in secretory cells
-Endoplasmic Reticulum (ER): continuous w/
nuc. env.
~Smooth ER: synthesis of lipids, metabolism of
carbs, detoxification, & Ca+2 storage
~Rough ER: protein, glycoprotein, membrane
synthesis (embedded rRNA)
-Vacuoles: large storage vesicles
-Endosymbiont theory: primitive euk. ate prim.
mitochondria
-Intermediated Filaments: bridge cable struc., 812 nm dia., cell shape, anchorage of organelles,
nuclear lamina
-Fluidity: phobic interactions are weak so phlp.
move around
-Molecule Movement:phlps move 2μm/sec,
proteins drift (mouse+human cell mixed up)
-Cholesterol: @ 37૦C, restricts fluidity,
-Dimer: molec made of 2 subunits
-Flagella: moves fluid over surface, cell
locomot, 10-200 nm length, undulating
-Cilia: fluid over surf., cell locom.,
perpendicular movement
~integral: penetrates phobic interior
~primary cilium: antenna of cell
-Dyneins: motor prot., bends organelle by
“walking”
~cross linking prot. stop sliding
-Centrosome: near nucleus, microtubule
organizer, 2 centrioles
-9+2: 9 doublets of microtub. & 2 in the center
~flagella & motile cilia
-Myosin: “walks” on m.filaments, shortens the
cell -> muscle contracts
-Centrioles: 9 triplets of m.tubules in a ring,
replicate b4 cell div.
-9+0: 9 doublets & no central pair
~nonmotile cilia & basal body
~mito & chloro are dbl memb., smaller rRNA,
circular DNA, autonomous
-Chloroplast: photosynthesis
-Thylakoids: flat sacs
lowers freezing temp
-Proteins in Membrane
~peripheral: not embedded, loosely attached
-Basal Body: anchor of flag/cil, 9+0
-Cell Wall: protects, maintains shape, prevents
excess water uptake
-Primary Cell Wall: first wall in young plant,
thin/flexible
~transport: channel, carrier,
~enzyme: active site on one side
~signal: relays a chemical msg thru memb
~recognition: some glycoproteins are tags that
are recognized by other cell membrane’s protein
~joining: gap/tight junction
~cytoskeleton/ECM: prot. Noncovalently bond
to m.filaments or ECM
-Cell-Cell Recognition: sorts cells into
tissues/organs in embryo, immune system
~glycolipids & glycoproteins
-Freeze Fractionization: cell is frozen & cracked
btwn the layers of phlp bilayer -> proteins span
entire memb/are on each side
-Membrane Traffic: only tiny np molec can
diffuse easily (not even water moves quickly)
~aquaporins: 3 billion water molec/sec
-Passive Transport: no ATP required
~diffusion: movement from high to low
~concentration gradient: region along which the
density of a chemical subst. incr/decr
~osmosis: diffusion of water across a selectively
permeable membrane
~isotonic: equal concentrations
~hypertonic :higher concentration
~hypotonic:lower concentration
~turgid: plant cell, rigid, memb pushing against cell
wall bc it is in a hypo solution (turgor pressure)
-Euryhaline: animals that can tolerate large
osmolarity changes in environ.
-Freshwater Fish: drink no water, excrete very
dilute urine
~flaccid: not rigid, isotonic solution
-Saltwater Fish: drink lots of seawater, gills
have special cells that act. Transport Cl- out and
allow Na+ to follow passively, kidneys excrete
Ca, Mg, & SO4
~plasmolyzed: cell membrane pulled away from cell
wall, hypertonic solution
-Contractile Vacuole:organelle functioning as a
bilge pump, pushes water out
-Facilitated Diffusion: transport using protein
but NO ATP
~channel: philic corridor
~gated channels: ion channels, opne/close in
response to stimulus (possibly electric)
-Active Transport: pump against gradient,
USES ATP
~sodium potassium pump: 3 Na+ from inside are
transported out using a P from ATP, 2 K+ enter prot.,
P leaves, K+ transports in
~voltage: electrical potential energy (separation of
charges)
~membrane potential: cytoplasmic side is negative,
extracellular side is positive, voltage is -50 to -200
mV (- means inside is neg compared to outside)
~electrochemical gradient: two factors driving
diffusion of ions (concentration gradient & membrane
potential {cations in, anions out})
~electrogenic pump: transport prot. That generates
voltage across the memb.
-Bulk Transport: movement of macromolec.
(proteins/ polysac.) in/out cell
~exocytosis: budding of a vesicle
~receptor-mediated endocytosis:ligand binds to
receptor, coated vesicle buds off
~phagocytosis: cellular eating (white blood cells)
Chapter 36: Water Potential &
Transport
-Water Potential: measurement of the tendency
of water to move from an area of low solute
conc. to high
-Apoplastic: water movement thru cell wall
-Symplastic: water route thru cytoplasm
-Casparian Strip: waxy strip that forces water to
move from apop -> symp.
-Xylem: dead cells that transport water up
-Phloem: living cells that transport sugars up
and down (thats why theyre living)
-Transpiration: loss of water vapor from plants
(evap but from plants), 90% of bulk flow is due
to transpiration
-Stomata: regulates gas exchange btwn plant &
outside (CO2, O2, H2O)
~regulated by abscisic acid (K+ into guard cell,
making it hypertonic -> water diffuses in ->becomes
turgid ->opens stomata, vice versa to close)
Chapter 44: Osmoregulation
-Osmoregulator: to control internal osmolarity
independent of environment
-Osmoconformer: to be isoosmotic with
environment
~can only be a marine animal
-Stenohaline: animals that cannot tolerate large
osmolarity changes in environ.
-Nitrogenous Waste: many metabolic wastes
need to be dissolved in water to be excreted,
comes from amino acids & nucleic acids
~ammonia (NH3): very toxic so it needs to be
heavily diluted -> freshwater animals
~urea (CO(NH2)2): low toxicity, land animals and
many marine animals
~uric acid (C5O3N4H4): nontoxic, doesn’t dissolve
so it can be excreted as a paste with little water loss,
reptiles and bird
-Filtration Systems in Organisms:disposes of
metabolic waste/control body fluid composition
(filtration->reabsorption-> secretion->excretion)
~protonephridia (flatworms): fluid filters thru flame
bulb, cilia filters, filtrate goes thru tubules and out into
the freshwater
~metanephridia (annelids): 2 meta. In each segment,
fluid goes into collecting tubule,
reabsorption/secretion happens btwn capillaries &
coll. Tubule, bladder secretes
~malpighian (insects): no filtration, malpighian
tubules secrete solutes from hemolymph into lumen,
water follows due to osmosis, goes to rectum where it
is reabsorbed, excretion (some insects can absorb
water from the air thru rectum)
~kidney (mammals): 85% of nephrons are cortical
(in renal cortex), others are juxtamedullary nephrons
that are longer and absorb more water
^blood press. Forces fluid from glomerulus into bowman’s
capsule ->filtrate moves thru proximal tubule, loop of henle,
& distal tubule->collecting duct moves processed filtrate to
renal pelvis->ureter->bladder