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ap bio unit two Cheat Sheet by

cell structure and function


Ribosomes = synthesize proteins; made of rRNA
Rough ER = compar­tme­ntalize cell and modify proteins synthe­sized by ribosomes
Smooth ER = detoxi­fic­ation of drugs, store calcium ions, and lipid production
Golgi Complex = package and fold proteins coming from ER; synthesize lysosomes
Mitoch­ondria = ATP production for cellular respir­ation; contain double membrane; inner foldings are called cristae
Lysosomes = break down waste; digest food by using phagoc­ytosis or engulfing nutrients to digest them with enzymes
Vacuole = water storage
Chloro­plast = photos­ynt­hesis
Centrioles = small, paired cylind­rical structures during cellular division, only in animal cells

Facili­tated Diffusion

passive transport that does not require energy
concen­tration gradient = particles move from highly concen­trated area of particles to less concen­trated area
channel proteins = hydrop­hilic passage for molecules to avoid hydrop­hobic core; ex: aquaporins
carrier proteins = slower than channel proteins; alter shape to transport hydrop­hilic molecules

Cell Size

the greater the SA/V ratio, the more efficient the cell is


hypertonic solution = more solute than inside of cell; water rush OUT OF CELL (hyper run outside); plasmolyze
hypotonic solution = less solute than inside of cell; water rushes INTO CELL (optimal for plants); turgid
osmore­gul­ation = cells can regulate their solute concen­tra­tions, maintain water balance, allows organisms to control their internal enviro­nment
water potential = tendency for water to move in one direction to another (water will flow from areas of high water potential to low) (high pressure to low) (low solute to areas of high solute)
osmosis = high water potential to low water potential
isotonic = same; flaccid

prokar­yotes vs eukaryotes

prokar­yotes (bacte­ria): cytoplasm, nucleoid (circular DNA), cell wall, cell membrane, ribosomes, flagella (movem­ent), capsule outside of membrane
eukaryotes (fungi, protists, plants) : nucleus, nucleolus, only plasma membrane, membra­ne-­bound organelles

Cell Membrane

small non polar molecules (N2, O2, CO2) can pass membrane easily, but larger polar molecules and ions cannot pass hydrop­hobic region alone
aquaporins = channel protein for water
channel proteins = a channel for smaller molecules like ions
carrier proteins = for larger molecules like glucose; once it enters inside, it spins to the other side of membrane
glycop­roteins and glycol­ipids help with cell signaling and the attachment of the cell to other structures
hydrop­hobic fatty acid tails repel charged and polar molecules

cell compar­tme­nta­liz­ation

eukaryotes compar­tme­ntalize their internal processes in membra­ne-­bound organe­lles; much more efficient
eukaryotic cells = RNA is made from DNA, RNA moves out of nucleus to ribosome or ER
prokar­yotic cells = RNA is made from DNA, RNA is immedi­ately converted into a protein because there is no nucleus or ER

endosy­mbiotic theory

how eukaryotic cells evolved form prokar­yotic cells?
early ancestor of eukaryotic cell engulfed a prokar­yotic cell, and the prokar­yotic cell became an endosy­mbiont (a cell living in another cell) which was the mitoch­ondria and chloro­plast


simple diffusion = passive; small non-polar molecules with concen­tration gradient
facili­tated diffusion = passive; small polar molecules and ions with concen­tration gradient; transport protein needed
osmosis = facilitate diffusion of water
active transport = energy needed; bulky molecules traveling against concen­tration gradient
endocy­tosis = taking bulk material INTO cell
three types of endocy­tosis:
1. phagoc­ytosis = cell engulfs large molecule, brings into cell, becomes food vacuole (phago­some)
2. pinocy­tosis = cell engulfs small solutes, bring into cell, becomes vesicles
3. recept­or-­med­iated endocy­tosis = receptor binds to cell. when solutes bind to receptor, forms vesicle that will bind to lysosome until solutes are digested
exocytosis = taking bulk material OUT OF cell; transport vesicle from golgi apparatus will fuse with membrane and release its contents outside of cell

plant cell vs animal cell

plants: cell wall, central vacuole, plasmo­des­mata, chloro­plast
animals : lysosomes, centro­somes, flagella


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