BIO230H1 Lecture Notes - Lecture 1: Secretion, Ldl Receptor, Triskelion
BIO230
Lecture 1
!
- Polarized+cell+–!cell!that!has!different!ends!(«polarized»!-!different)!(Ex:!nervous!
cell,!epithelial!cell);!
!
- Three%types%of%pathways:%
a) forward!(Biosynthetic+pathway);!
b) reverse;!
c) endocytosis!(Endocytic+pathway);!
!
- Constitutive+secretory+pathway!(functions!in!all!cells);!
- Regulated+secretory+pathway!(functions!in!specialized!cells!when!the!signal!is!
received)!;!
+
- Endocytosis:++++a)!Recycling!(cargo!sent!back!to!the!same!side!of!the!cell)!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!b)!Transcytosis!(cargo!sent!to!the!opposite!side!of!the!cell)!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!c)!Degradation!(cargo!sent!to!the!lysosome)!!
!
Three%membrane%changes:%
- Invagination+–!the!action!or!process!of!being!turned!inside!out!or!folded!back!on!
itself!to!form!a!cavity!or!pouch;!
!
- Fission!-!the!division!of!a!cell!(or!body,!population,!or!species)!into!two!or!more!
parts!and!the!regeneration!of!those!parts!into!separate!cells;!
!
-!Budding+-!membrane-bound!is!formed!compartment!outside!from!the!cell!rather!
than!from!inside!the!cell;!
!
!
-!LDL+–+low!density!lipoprotein,!binds!cholesterol;!LDL+receptor++
(Shown!in!the!example!of!how%cell%collects%resources%by%endocytosis)!
!
- Phagocytosis!–!a!form!of!endocytosis!;!
!
- SNARE+proteins+(v-SNAREs+and+t-SNAREs)+–+proteins!required!for!a!fusion!of!two!
membranes;!specify!which!membranes!fuse!and!conduct!the!process+
+
v-SNARE!–!vesicular!SNARe!
t-SNARE!–!target!SNARE!
!
- Clathrin+–!a!protein!required!for!a!coat!of!clathrin-covered!vesicles!(third!type);!
drives!vesicle!invagination!event!
Has!a!triskelion!structure:!3!heavy%chains!and!3!light!chains!
!
- Dynamin+–!a!protein!equired!for!clathrin-covered!vesicles!in!order!to!finish!it!
(budding!off).!Dynamin!drives!fission!after!vesicle!invagination!events.!
!
+
-+The+ESCRT+Complex++-+a!protein!omplex!which!is!required!for!budding!!of!the!
vesicle!
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BIO230H1 Full Course Notes
Verified Note
42 documents
Document Summary
Polarized cell cell that has different ends ( polarized - different) (ex: nervous cell, epithelial cell); Three types of pathways: forward (biosynthetic pathway), reverse, endocytosis (endocytic pathway); Constitutive secretory pathway (functions in all cells); Regulated secretory pathway (functions in specialized cells when the signal is received) ; Endocytosis: a) recycling (cargo sent back to the same side of the cell) b) transcytosis (cargo sent to the opposite side of the cell) c) degradation (cargo sent to the lysosome) Invagination the action or process of being turned inside out or folded back on itself to form a cavity or pouch; Fission - the division of a cell (or body, population, or species) into two or more parts and the regeneration of those parts into separate cells; Budding - membrane-bound is formed compartment outside from the cell rather than from inside the cell; Ldl low density lipoprotein, binds cholesterol; ldl receptor (shown in the example of how cell collects resources by endocytosis)
