cell biology

a small GTPase that regulates cargo binding and release on exprtins and importans, based on whether it is in GTP or GDP from

nucleosome

nuclear lamina

telomere, replication origin and centromere

unique N terminal AA sequence required for a protein to be directed to a specific organele

importins and exportins

during assembly the NLSs are 'hidden' inside the structure of the ribosome

glycerol backbone, 2 non polar FA hydrocarbon tails and a phosphate containing head group

sphingomyelin and phophotidylcholine

• -all cholesterol
• -most phospholipids (initally on the cytoplasmic half because enzymes ans substrates are in the cytoplasm)
• -also involved heavily in detox reactions (50% with peroxisomes handling the other 50%)

• -require an alpha helical domain of hydrophobic amino acids(at least 20 to pass all the way thru membrane)
• -can pass through once or multiple times
• CAN ONLY BE ROMOVED WITH THE USE OF A DETERGENT

largely exposed and are COVALENTLY tehterd to either a phospholipid or glycolipid

• -occurs in the lumen of the er(N) and golgi(N and O)
• -CHO is always found is outer leaflet of the plasma membrane (because enzymes that add the carb are inside the lumen of said organelles)

• c-mostly sphingomyelin (choline containing) and cholesterol, also some phosphotidylcholine
• s- thicker than the phospholipid bilayer

bodies present in many undividing cells made up of residual bodies of lysosomal degredation

• f-mechanical strength
• s- thought to be 8 tetramer filaments woven into a rope like structure
• p- can be used to determine origin of tumor cells because different cell types have different IF

• Keratins Epithelium
• Vimentin Mesenchymal cells
• Desmin Muscle
• Gilial fibrillary Glial cells
• Neurofilaments Neurons
• Nuclear lamins surrounding internal NM NUCLEAR LAMINS ARE FOUND IN ALL CELLS TYPES

• microtubule organzing center
• anchors minus end of a microtubule
• has a pair of centrioles perpendicular to eachother

• MT motor that moves toward the + end of a MT (away from centrosome)
• ATP driven

• MT motor that moves toward the - end of a MT (toward centrosome)
• ATP driven

• f-determines postion of organelles and directs transport
• s- 13 profilaments form a hollow MT
• c- gamma tubulin provides nucleus and starts negative end, beta/alpha subunits attach(GTP) and detach(GDP) only at positive end

• -made of MT in a (9+2) arrangement
• -anchored to cell membrane by a basal body (which has same structure as centrioles- 9 sets of triplets)
• f- movement- DYNEIN, using ATP, slides one doublet past another creating bend

• determine cell shape
• made of actin, the most abundant protein inside cells
• grows and shrinks at - and + ends
• goverened by ARPs

actin binding protein that forms supporting network for plasma membrane of RBC

• defects mitotic spindle
• prevents mitosis by stabalizing MT polymer and preventing dissasembly and thus cell division
• binding site on beta tubulin

• mobile in the intermembrane space of a mtch
• its release will signal apoptosis

• 37 genes
• 2 rRNA, 22 tRNA and 13 protein

• combo of 2 phopholipds that are combined in the mtch to strengthen the IMM to withstand the PMF
• -an example of a PL not made in the ER

• -H+ pump- to keep acidic inner environmetn required to activate enzymes
• -glycoprotein coat- protects inner membrane from acidic environment
• -transport channels- eject broken down molecules

results from a absence of hexosaminidase A, which breaks down glycolipids in the lysosome

• -contain catalase
• -beta oxidize FA (as do mtch), syn bile, syn
• PLASMOLAGENS USED IN MYELIN
• -have a single membrane(not present in neurons)
• -can adapt very fast to change in conditions (ie ingestion of EtOH)
• -2nd major O2 user next to mtch

G1/S - (before replication) environment is assessed for favorable conditions, is DNA intact

G2/M- (before division)DNA is checked for completion and accuracy, is DNA intact

disappearance of nuclear envelope

when the chromosomes are lined up in the center of the cell

hold sister chromatids together and are degraded at anaphase allowing SC to be pulled apart

condenses DNA, only active during M phase

• - MT shorten to pull SC apart by motor proteins on the kinetocore
• - SC acually roll down MT toward pole with the help of a motor protein that is part of the kinetochore

mitotic spindles pulled apart toward the cell wall via motors on the centrosome and on the MT anchoring the centrosome to the periphery

metaphase/ anaphase transition

proteins that attach to the centromere of a chromosome and connect to (+) MT during cell division

form contractile ring during cytokinesis

phosphorylation of lamins

NE disassembly happens at prometaphase

ATP production in the mitochondria

• apoptosis- dying cell phagocytosed
• no inflammation or damage to adjacent cells
• PM stays intact through whole process
• cell shrinks

• -ALWAYS activated during apoptosis
• - cys proteases that degrade the insides of the cell
• -always around inactive, waitng to be activated
• -can cause cascade, activating other caspases

• -REGULATE APOPTOSIS in a pro- and anti- manner
• - when deprived can cause OMM to become permeable, thus releasing cyt c, which will activate caspases

• phosphotidylSERINE on external leaflet of membrane, put there by a non-specific scramblase
• -ALWAYS HAPPENS WITH APOPTOSIS

• -via non specific transport proteins (non targetting)
• -NO SNARES on mitochondria so there can be NO VESICULAR transport from ER or golgi
• -mtch channels are only wide enough for UNFOLDED AA to go thorugh

always folded prior to intake into organelle except in the case of mtch

diffusion

enzyme in SER involved in detox reactions

intracellular Ca

ER vesicles

required to enter the secratory pathway and is at least 8 hydrophobic aa long

• -recognizes ER signal sequence and shuttles ribosomes that are translating proteins with ER signal sequence to the ER and aid connections and opening translocon channels
• -translation stops while SRP is bound

prevents disulfide bonding from occuring in the cytosol

added in ER, can act as a sorting signal to direct membrane proteins to specific areas of the PM(lipid raft, calveoli)

membrane proteins that enter the secratory pathway, mtch membane proteins do not go this route

• -binding proteins that aid protein folding by binding temporarily to hydrophobic regions
• -hsp-70 in cytosol
• -BIP in lumen of the ER, release is required to exit ER
• -will give up if protein wont properly fold and protein will be ubiquitinated

transmembrane Cl- channel that is defective in cystic fibrosis. It is not that the channel is non-functional, rather it slightly misfolds and is never released from BIP and is stuck in the ER then degraded

trans golgi

-involved in endocytosis from PM and movement from trans golgi to the endosome

-a type of coat protein that will initiate budding, by covering outside and then must fall off to allow fusion

-not part of constitutive p/w

• -two types V(vesicle) and T(target)
• -complimentary pairs, that excrude water when they bind and allow membranes to fuse
• -targetting signals(and receptors) of vesicles
• - no T-SNARES on mtch or mitochondria

tethering proteins that aid connection of complimentary SNARE joining

• -groups on glycoproteins and glycolipids that give the outer leaftlet its negative charge
• - added in the golgi

formed in the golgi

thick layer of CHO that gives a 'cushion' to the PM

• mannose 6 phosphate- targetting signal for lysosome
• -added to N linked sugar(which is added in the ER) on the acid hydrolase in the cis-golgi.
• -in the trans glogi M6P binds a M6PR, which destines it for the lysosome
• - acid hydrolase is disassociated from the M6PR in the low pH of the lysosome, M6PR is then recycled

by the lysosome in autophagosomes

• lipid rafts
• (glycophphotidylinositol)

binds cytosolic side of certain receptors as well as clarithrin, thus starting endocytosis

• -internalized by receptor mediated endocytosis
• - localized in the coated pits even before binding it ligand (LDL)

unlike LDLr, the ligand and EGFr(and most other signalling receptors) are targetted to the lysosome for degradation, this is one way to down regulate receptors, by not recycling them

• - NEVER FUSE WITH LYSOSOMES(think microbe entry, INDISTINGUISHABLE FROM LIPID RAFTS
• -act as signalasomes
• -small invaginations of PM, seen especially in endothelial cells, but absent in neurons
• - maintained by caveolin

• made of rRNA(made in nucleolus)
• large subunit- 3 rRNAs and proteins
• small subunit- 1 rRNA and proteins (18s)

• -start at gamma tubulin at - end of MT located in the MTOC
• - grow and shrink on + end
• - target of many anti cancer drugs(prevent mitotic spindle formation)

• - grow at + end, shrink at - end
• - shape PM
• - form microvilli
• - make lamellipodia
• - contraction causes invagination during division

13, 14, 15, 21, 22

binding site for + ends of MT so sister chromatids can be pulled apart

• - those destined for the cytosol, peroxisome and mitochondria
• **mtch recieves NO vesicular transport**

- facilitate release of SNAREs for recycling

ER retention signal

46(4n)-> meiosis 1-> 23(2n)-> meiosis 2-> 23(1n)