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AP Biology Unit 2 - Cell Organelle & Communication Cheat Sheet (DRAFT) by

Unit 2 of AP Biology, Cell Organelles, and Communication Review for the AP Exam.

This is a draft cheat sheet. It is a work in progress and is not finished yet.

cell theory

1. All things are made of cells
2. Cells are the basic units of structure and function in all living things
3. All cells come from pre-ex­i­sting cells

endosy­mbiotic theory

Mitoch­­ondria and chloro­­plasts were formerly small prokar­­yotes that began living within larger cells, may have gained entry as undigested prey or parasites.
all eukaryotic cells came from bacterial cells that lived together
proof:all chloro­plasts and mitoch­ondria have own DNA and are autonomous (existing and functi­oning as an indepe­ndent organism)

cell surface area to volume

smaller cell is faster and more efficient at supplying materials and removing waste than larger cell
once volume becomes too great for area of cell membrane, pathway is triggered and cell divides

water potential - def and vid

 

osmotic potential

potential of water molecules to move from a hypotonic solution (more water, less solutes) to a hypertonic solution (less water, more solutes) across a semi permeable membrane

tonicity

- turgor pressure - pressure that water molecules exert against cell wall (consi­dered normal GOOD)
- plasmo­lysis - cells shrinking away from cell wall
- cytolysis - same as lyse

diabetes

type 1
insulin isn't produced, beta pancreatic cells damaged
type 2
insuli­­n/­g­l­ucose receptors not working
Hyperg­­ly­cemia (high blood sugar), hypogl­­ycemia (low blood sugar). Antagonist to insulin is glucagon.

prokar­yotic cells

unicel­lular bacteria
nucleoid region: DNA floating in cytoplasm, no true nucleus or nuclear membrane
considered first form of life - were most likely anaerobic
cell membrane: regulates transport; selective permea­bility
cell wall: protective layer external to cell membrane
*does not contain phosph­olipid or transport proteins
*pepti­dog­lycan?
bacterial cell wall is often target for antibiotic treatment
DNA exists freely in cytoplasm as closed loop
ribosomes: protein synthesis location
capsule: outside of cell wall; made of carboh­ydrate
* limit the ability of phagocytes to engulf the bacteria
* cannot be washed off easily
pathogenic (causes disease)
pills make it stick and can't wash off

prokar­yotic cells

prokar­yotes vs eukaryotes

pro
euk
No Membra­ne-­Bound Organelles
Membra­ne-­Bound Organelles
No Nucleus (single Circular DNA)
Multiple Linear DNA
Free Ribosomes and cell wall
Histones on DNA

endome­mbrane system

all the different membranes within a eukaryotic cell’s cytoplasm
divide the cell into compar­tments (organ­elles!)
nuclear membrane
double membrane that encloses the cell nucleus
er
connected to the nucleus; allows for reactions, membra­neous;
rer
proteins, has a lot of ribosomes
ser
lipids, respon­sible for the detoxi­fic­ation of harmful chemicals
golgi body
packaging in membrane and signals for export
lysosomes
used for intrac­ellular digestion and apoptosis, also to fuse w another vesicle to break down using its hydrolytic enzymes
vesicles
may carry hormones that help w body regula­tion, merges w plasma membrane, releases contents into the external envi, lysosome is a type of vesicle
vacuoles
water and solutes; large and central in plants
cell membrane: regulates transport; selective permea­bility
modifi­cations for cell specif­icity :
muscle cell has more rer bc of its need for protein
liver cell has more ser bc of its role in detoxi­fic­ation

rest of organelles

nucleus
holds DNA and nucleolus (where ribosomal subunits are made)
mitoch­ondria
double membrane; outer is smooth and inside is folded with enzymes to make ATP (site of cellular respir­ation)
ribosomes
site of transl­ati­on-­protein synthesis; made of rRNA and protein
cytosk­eleton
Microf­ila­men­ts-­con­tra­ctile protein, gives shape, movement within cells; Microt­ubu­les­-ce­ntr­ioles, cilia, flagella, spindle fibers
ANIMAL
lysosomes
contain enzymes; used for intrac­ellular digestion and apoptosis
Centrioles
used in cell division
plants
Chloro­plast
double membrane; site of photos­ynt­hesis
Cell wall
middle lamell­a-p­ectin; primary cell wall-c­ell­ulose; secondary cell wall- lignin

nervous system

Function; sensory input, motor function, regulation
Structure; neuron, axon, dendrites, synapse
Polarized neuron; Na+ outside, K+ and Cl- inside
Depola­riz­ation moves Na+ into the neuron, generating an action potential
Repola­riz­ation exchanges Na+ and K+ through the sodium­-po­tassium pump
At the synapse, calcium channels open to allow calcium to rush in, stimul­ating release of neurot­ran­smi­tters
Neurot­ran­smi­tters released into synapse to generate action potential for motor neurons or muscle cells
 

link for signal transd­uction pathway

cell signaling / signal transd­uction

reception: when a receptor protein picks up a signaling molecule on the surface in the phosph­olipid bilayer. are other ways...

transd­uction: series of relay molecules or other protein complexes will usually use ATP to transfer the signal down a signal transd­uction pathway and activate a response

response: changes in enzyme activity, gene expres­sion, and ion channel activity

inacti­vation: is when response stops - can be apoptosis or a halt of the response.

transd­uction

a phosph­ory­lation cascade
phosph­ory­lation - addition of a phosphate group, generally from ATP to a protein or other organic molecule which turns many protein enzyme son and off
stp is merely a lot of different molecules being involved and carrying a signal from the original site of reception to then carry out a response

second messangers

cAMP
broken down even more is cyclic adenosine monoph­osp­hate, intrac­ellular messenger
calcium ions
inositol tripho­sphate
can occur on nuclear level
genes turning on or off by activation of proteins called transc­ription factors in nucleus of cell and will activate or inactivate causing transc­ription of RNA which is then a messenger and is translated into a protein
organismal response
fight or flight response: encounter lion, could fight it or run away, activated by adrenaline
inacti­vation
can occur both in inacti­vation of simple nuclear responses or can be apoptosis (clean programmed cell death)
phagoc­ytosis
one cell eats or breaks down another cell, used both in immune system and apoptosis
apoptosis
cells called phagocytes consume cell that have sent out signals that occur because of other complex signals that say they must disint­egrate and be consumed
phagocytes
cyte (cell), phag (consume)

intrac­ellular receptors

intrac­ellular receptor proteins occur within one cell
Is when a hormone or other ligand can go through phosph­olipid bilayer bc it is hydrop­hobic
has a receptor protein inside the cytoplasm of the cell
this often reacts with that receptor protein creating a hormone receptor complex that can enter into nucleus of cell and create RNA subscr­iption?

ligand gated ion channel

like a door or portal, when signaling molecule attaches to active site on this "­gat­e" will open, usually involved in ion channels, a lot of ions will pass through creating a concen­tration gradient, on the way out will create ATP and energy of that will be harnessed by the cell

G protein coupled receptors (gpcr)

involved at the surface of the cell a lot of the time w epinep­her­ine­//a­dre­niline, affects the fight or flight respsonse in animals. hromone in the endocrine system and neurot­ran­smi­tters in the synaptic cells

protein kinases (rtks)

kinase­-enzyme that catalyzes transfer of phosphate groups from ATP to ADP when it goes through hydrolysis (water breaking off one phosphate ion from ATP). rtk-re­ceptors that when they receive a signaling molecule at their active site, form an unphos­pho­rylated dimer, makes ATP connect to this tyrosine which is a protein and that activates the rtk and turns it into a phosph­ory­lated dimer. Then inacti­vated relay proteins attach to the phosphates on the dimer and are activated and result in response

active transport methods

passive transport

no added energy required
movement of molecules from area of high to low concen­tration
concen­tration gradient
difference in concen of mlcs across a distance
diffusion
carbon dioxide and oxygen can pass through membrane bc small and non polar (soluble in lipids)
facili­tated diffusion
polar molecules (water) need to pass through pore made by transport protein
osmosis
diffusion of water, water moves from high to low, amount of solute needs to be payed attention to
solute
solid that is dissolved in a solvent
solvent
liquid
hypertonic
high amount of solute, low amount of water in SOLUTION
hypotonic
low amount of solute, high water
isotonic
solute concen inside and outside are the same
isotonic
water moves back and forth in equal amounts (no net movement), cell maintains shape
water moves from high concen of WATER to low concen of WATER
hypo to hyper
contra­ctile vacuole
ex paramecium live in hypotonic, use these to collect excess water and then contract to push water out
our cells pump solutes out of cytosol to bring outside concen closer to inside
plants
take in water through their roots through osmosis
1. molecule binds to carrier protein, 2. carrier protein changes shape, 3. protein releases the molecule to the outside, 4. protein returns to og shape
second way of fd: ion channels, membrane proteins that allow only one specific type of ion through
factors that affect the rate at which mlcs move across membrane:
temp- higher temp
starting concen- extreme diff in starting concen
size of particles- small
all diffuse at a faster rate

active transport

requires added energy (ATP)
moves from low to high concen­tration
up the concen­tration gradient (sodium potassium pump)
membrane pumps
carrier proteins that moves substances from low to high concen­tration
endocy­tosis (vesicle movement)
brings items into the cell, process b y which cells ingest external fluid, macrom­ole­cules or other large particles. Phagoc­ytosis is cell eating and Pino cytosine is cell drinking
exocytosis (vesicle movement)
process by which a substance is released from a. cell through a vesicle that transports it to the cell surface and fuses w the cell membrane
 
can fuse bc both made of phosph­oli­pids, layers press into each other and phosph­olipids rearrange a little so can open up their contents to the outside of the cell
ALL REQUIRES ENERGYYYY
 

cytosk­eleton

a complex of mesh protein filaments that extends throughout the cytoplasm
maintains cell shape
controls position of organelles within cell by anchoring them to plasma membrane
cytopl­asmic streaming
flow of cytoplasm
anchors cell in place by intera­cting w extrac­ellular elements
includes microt­ubules and microf­ila­ments
microt­ubules
hollow tubes made of tubulin protein which makes up cilia flagella and spindle fibers
microf­ila­ments
made of actin filaments, support shape of cell
animal cells form cleavage furrow
amoeba to move by sending out pseudopods
skeletal muscles contract as they slide along myosin filaments

cytoplasm

Separates the internal enviro­nment of the cell from the external environmen
Phosph­olipid bilayer (selec­tively permeable; amphip­athic)
Fluid mosaic model (in motion; proteins, choles­terol, glycop­rot­eins, and glycol­ipids among phosph­oli­pids)
membrane is hydrop­hilic on the inside and outside, hydrop­hobic within the membrane

centriole, centro­some, mtoc

non membranous structures that lie outside NUCLEAR membranes
organize spindle fibers and give rise to spindle apparatus
two centrioles make up a centrosome (ANIMALS)
PLANTS have microt­ubule organizing center (mtoc) which does the same thing

cell membrane // proteins

give diff types of membranes their unique props
help w facili­tated diffusion and active transport
connect cells together
partic­ipate in signal transd­uction
act as marker for cell identi­fic­ation
integral
permanent part of the membrane
peripheral
transi­ently (not perm) associated w either membrane or integral proteins
associ­ations can be hydrop­hobic, electr­ost­atic, or non covalent
integral monotopic proteins
attached to only one of two leaflets don't span across membrane
transm­embrane (are amphip­athic - hydrop­hobic and phillic)
span bilayer, can be bitopic spanning across membrane once or polytonic (more than once)
lipid anchor proteins
covalently attached to lipids in the bilayer
post transl­ational changes to integral and peripheral
addition of fatty acids, diacyl­gly­cerol, phrenyl chain,
hydrop­hobic affect
water molecules want to interact w each other so badly, anything getting in the way of their hydro bonds results in decreased entropy
detergent will disrupt transm­embrane proteins bc r amphip­athic and will get them out of the membrane
2 types of transm­embrane proteins
a helical
found in all membranes
b barrel
only in outer membranes of gram neg bacteria, mitoch­ondria, chloro­plasts
function as gateways allowing specific substances to pass across the membrane
may undergo confor­mat­ional changes
most transm­embrane proteins are glycos­ylated, sugar residues always present on non cytosol leaflet of bilayer
as a result, cell surface is covered in carbs that form cell coat

channels / proteins

apoptosis // capases

 
pathways involving enzymes called capases carry out apoptosis
apoptosis is similar in single celled yeast and in mammalian cells means mechanism for apoptosis evolved early in the evolution of eukaryotic cells

long distance signaling

in animals or humans through endocrine system - when specia­lized endocrine cells withing your glands and lymph nodes and lymphatic system will secrete things and those will travel through you blood and when reach any target cell, that will be effected and give a reaction. hormone ex: oxytocin, epinep­herine, it is transp­orted form endocrine system through the circul­atroy system

local signaling

paracrine signaling - secreting cells, secrete molecules that diffuse from cell and whenever they hit a target cell w a receptor on surface that fits with molecule then will have an induced effect

synaptic signaling - a motor neuron (effer­ent­-se­nding signals out) will send some sort of molecule (the effect) across the synapse and will affect a target cell that is stimulated and then has another action potential or response. In muscle contra­ction, mol would be acetyl­choline

commun­ication by direct contact

gap junctions - bet animal cells, junctions that allow molecules to play readily bet adjacent cells w/o crossing the plasma membrane

plasmo­desmata - bet plant cells

cell to cell recogn­ition - two animal cells may commun­icate by intera­ctions bet molecules protruding from their surfaces. protiens or other molecules on the surface of cells jutting out can react w each other. they seem to fit together like a specific protein and a specific substrate