Cell trafficking

Question 1

Name the 3 cell signaling pathways steps

Answer 1

1 Target cell rec binds to ligand
2 transduction - activation of intracellular messenger
3 cell response

Question 2

Name the 3 classes of receptor

Answer 2

GPCR
Enzyme coupled receptor
Ion Channel receptor

Question 3

Which of the class of receptors is serpentine

Answer 3

GPCR

Question 4

Explain the pathway of GPCR

Answer 4

g protein binds to gdp (inactive)—> binding of ligand—> GDP converts to GTP and bind to alpha subunit—–> alpha subunit brings in changes—-> these changes require gtp to convert to gdp——> gdp inactivates gpcr

Question 5

Which pathway does Gq activate

Answer 5

Phospholipase C which forms IP3 and DAG

IP3 opens Ca and DAG uses them to activate kinase and cause changes

Question 6

Which pathway does Gs activate

Answer 6

By adenylyl cyclase —-> activates cAMP—-> binds pKa—–> dissociates regulatory subunit

Question 7

What are 3 types of Enzyme Coupled receptor

Answer 7

i) Receptor tyrosine kinase
ii) Tyrosine kinase associated receptor
iii) Serine threonine kinase

Question 8

Give the mechanism of Receptor tyrosine kinase

Answer 8

ligand binds—> dimerization—-> partial activation——> cross phosphorylation—-> Ras activation——–> MAP kinase

Question 9

Which toxin inhibits Gi

Answer 9

Cholera toxin and Pertussis toxin

Question 10

what are the 3 types of endocytosis

Answer 10

Phagocytosis
Pinocytosis
Receptor mediated endocytosis

Question 11

Steps involved in phagocytosis

Answer 11

binding of subs to rec—-> pseudopod formation—-> phagosome formation—> binding of phagosome with lysosome to form phagolysosome —-> digestion of subs

Question 12

Both endocytosis and exocytosis require atp (T/F)

Answer 12

True

Question 13

What mechanism does receptor mediated endocytosis follow

Answer 13

Clathrin mediated endocytosis

clathrin also transports trans golgi to lysosome

Question 14

What organelle is the distribution center for proteins

Answer 14

Golgi

From ER to vessicles

Question 15

What are the post translational modifications that take place in the Golgi apparatus

Answer 15

modifying N oligosaccharide on asparagine
Adding O oligosaccharide on serine and threonine
Adding mannose 6 phosphate to proteins from lysosome

3. N acetylglucosaminyl 1 phosphotransferase

Question 16

What are the sorting center for material from outside cell and Golgi

Answer 16

Endosome

send to lysosome for destruction and golgi for further use

Question 17

I cell disease is also known as

Answer 17

Mucolipidoses type 2

Question 18

genetic makeup of I cell disease

Answer 18

Autosomal recessive

Question 19

Reason of I cell disease

Answer 19

Loss of enzyme N acetylglucosaminyl 1 phosphate which adds mannose 6 phosphate to proteins

Question 20

Mechanism of I cell disease

Answer 20

def in N acetylglucosaminyl 1 phosphate—–> failure of golgi to phosphorylate mannose—-> enzyme secreted extracellularly than in lysosome —–> lysosome def in dig enzymes—–> Buildup of cellular debris in lysosomes called inclusion bodies

Question 21

Symptoms of I cell disease

Answer 21

Coarse Facial features
**Gingival hyperplasia
**corneal clouding
claw hand
restricted joint movement
kyphoscoliosis

Question 22

What does dysfunctional SRP cause

SRP- signal recognizing particle

Answer 22

Accumulation of protein in cytosol

Question 23

COPI and COPII transport

Answer 23

COPI - retrograde (Golgi to Golgi or cis golgi to ER)
COPII - anterograde (ER to cis golgi)

Two steps forward one step back

Question 24

Signal ______ is the process where a receptor protein changes in response to binding a ligand and activates the second messenger proteins.

Answer 24

Transduction

Question 25

Gq protein activates the enzyme _____

Answer 25

Phospholipase C