cell organelles

Question 1

main site for protein synthesis, lipid synthesis, protein folding, and storage of calcium

Answer 1

endoplasmic reticulum

Question 2

site of post-translational modifications of proteins and lipids

Answer 2

golgi apparatus

Question 3

where are the enzymes used in redox reactions stored?

Answer 3

peroxisomes

Question 4

between a liver hepatocyte and a pancreatic oxocrine cell, which has the largest percentage of rough ER?

Answer 4

pancreatic exocrine cell

Question 5

3 important functions of the rough ER

Answer 5

1. modification and assembly of protiens
2. segregation of proteins for intracellular use
3. exporting molecules from the cell

Question 6

in protein synthesis, what directs the mechanism of how secretory proteins get to the ER?

Answer 6

a signal sequence

Question 7

how does the smooth ER differ from the rough ER?

Answer 7

1. lacks ribosomes

2. has tubular cisternae

Question 8

what are 6 important functions of the smooth ER?

Answer 8

1. glycogen metabolism
2. lipid synthesis
3. phospholipid synthesis
4. detoxification
5. steroidogensis
6. calcium regulation

Question 9

the golgi apparatus has two distinct faces. which face is the entry and which is the exit?

Answer 9

cis = entry
trans = exit
- cis is adjacent to the ER, trans is closer in range to the nucleus and plasma membrane

Question 10

in clathrin-coated vesicle transport, what mediates clathrin binding to the vesicle memebrane?

Answer 10

adaptins

Question 11

what type of vesicle transport, transports products between stacks of the golgi - and from the ER to the golgi?

Answer 11

COP vesicles (coat protein vesicles)

Question 12

how do lysosomes maintain a acidic intracellular enviroment?

Answer 12

through the use of a ATP-dependent H+ pump

Question 13

three pathways for intracellular digestion

Answer 13

1. phagocytosis
2. autophagy “self-eating”
3. receptor-mediated endocytosis

Question 14

Familial hypercholesterolemia

Answer 14

• mechanism of cholesterol uptake is disrupted
• characterized by: increase in LDL, the predominant cholesterol transport protein in the PLASMA
• primary defect: mutation in the gene encoding for the LDL receptor – receptor is incapable of binding LDL, receptors that bind are at reduced capacity, or receptors bind normally but are incapable of internalization
• high levels of LDL lead to atherosclerotic plaques

Question 15

functions of peroxisomes

Answer 15

• synthesis/ degradation of hydrogen peroxide
• beta-oxidation of FAs
• bile acid and cholesterol synthesis
• detoxify alcohol

Question 16

Zellweger spectrum disorders

Answer 16

• peroxisome biogenesis disorders
• cause a defect in the assembly of the peroxisome through a defect in any of the 12 genes that encode for proper assembly
• most serious: absence or reduced number of peroxisomes in the cell
• if present in patients at birth – no cure of effective treatment – aka: death with the first year

Question 17

mutations in mitochondria RNA have been linked to over 200 disease– often, what do these mutations prevent?

Answer 17

tRNA aminoacetylation