From memory cards

Question 1

Endoplasmic Reticulum’s Design

Answer 1

ER consist of cisternae, tubules, and vesicles

Subdivided into three categories:

1. Smooth, without ribosomes attached at face
2. Rough, possessing ribosomes in its membrane
3. Transitional, vesicle transport to Golgi site

vesicles leave ER from transitional ER

ER divided into two compartments, the endoplasmic (outside) and the cytosolic compartments (inside)

There are also leaflets: exterior is called the EXOCYTOPLASMIC LEAFLET
PROTOPLASMIC LEAFLET

Question 2

ER, explain everything

Answer 2

All protein production begins on a free ribosome, if it’s destined for the golgi, lysosomes, or secretion, protein will continue to ribosomes on the rough ER

ER has three subdivisions: Smooth, rough, and transitional (where vesicles bound for Golgi depart)

ER is identified by cisternae (flat stacks), vesicles, and tubules

The lumen of the cisternae is continuous with the ECM, and whose phospholipid elements are identified by the inner leaflet (the cytoplasmic leaflet) and the outside (the endocytoplasmic leaflet). the two compartments are referred to as the endoplasmic side (the exterior, or lumin) and the cytoplasmic side (the interior side)

Question 3

Signal Pathway Hypothesis

Answer 3

Proteins begin on free ribosomes before than translocated either while being synthesized ….

signal is 1st synthesized ( roughly 20 amino acids long): sequence is recognized by SRP which binds to it and halts synthesis; SRP translocates peptide to membrane via SRP receptor, SRP relinquishes peptide while HSP 70 keeps peptide unfolded and BiP (another hsp 70 protein) pulls it through a translocon channel; inside n-linked glycosylation occurs

signal is cleaved inside

Question 4

Signal Hypothesis One More Time (with feeling)

Answer 4

1. signal sequence synthesized first
2. SRP recognizes, binds, and translocates to membrane
3. SRP binds to SRP receptor, SRP relinquished
4. peptide synthesis resumes
5. BiP assists in pulling through translocon
6. hsp 70 maintains unfolded state
7. sequence is cleaved
8. inside n-linked glycosylation occurs (n-acetylglucosamie)

Question 5

Membrane recognition and fusion

Answer 5

1. Facilitated fusion and specific

Question 6

GPI

Answer 6

glycosolphosphatidol is GPI, attached to proteins bound for membrane

Question 7

Protein folding and sorting

Answer 7

1. proteins that are misfolded have a glucose attached to them
2. sent to calreticulin

Question 8

calreticulin

Answer 8

a chaperone enzyme responsible for adding a glucose residue to a misfolded protein

Question 9

phospholipids 1) where they are synthesized

                  2) from what they are synthesized 
                  3) etc

Answer 9

synthesized on cytoplasmic side of the ER

from glycerol

must remain in cytoplasm unless transferred to lumen by flippase proteins

Question 10

Glycosylation WHAT is it, WHERE is it, HOW does it occur

Answer 10

1) modification of carbohydrates on glycoproteins and proteoglycans received by the ER
2) occurs by glycosyltransferase
3) includes modifications of N-linked oligosaccharides on glycoproteins
4. includes O-linked glycosylation: addition of carbohydrates to serine and threonine

Question 11

O-linked glycosylation and N-linked glycosylation in the Golgi apparatus

Answer 11

O-linked glycosylation is the addition of a carbohydrate to threonine and serine

n-linked is when a modification of an oligosaccharide no a glycoprotein occurs

Question 12

Who synthesizes sphingomyelin and glycosphingolipids

Answer 12

the golgi apparatus

Question 13

constitutive/facultative secretion

Answer 13

facultative only responds to certain ECM signals

constitutive is happening all the time (think glycoproteins)

Question 14

Lysosomal Pathways

Answer 14

signal molecule is mannose-6-phosphate

residues found on glycoproteins, destined to become acid hydrolases

Question 15

Mannose-6-phosphate

Answer 15

targeting signal for lysosomal enzymes

found on glycoproteins destined for lysosomes

molecules are destined to become acid hydrolases

residues are phosphorylated to protect them from being removed by enzymes in the CGN

TGN concentrates these labeled glycoproteins into transport vesicles

transport vesicles
lose clathrin coat
are transported along microtubules to fuse with late endosomes

Question 16

the neutralization of new lysosomal enzymes

Answer 16

mannose-6-phosphate is the targeting signal for lysosomal enzymes bound to become acid hydrolases, which are glycoproteins initially

they are phosphorylated to protect them from being removed by enzymes in the CGN

transported from the TGN in transport vesicles, lose their clathrin cloat, transported along microtubules, and fuse with late endosomes