DSA: Cell Organelles

Question 1

4 functions of the ER

Answer 1

1. Protein synthesis
2. Lipid synthesis
3. Protein folding
4. Storage of calcium

Question 2

Golgi apparatus functions

Answer 2

Post translational changes on proteins and lipids, trafficking

Question 3

% of pancreatic exocrine cell membrane that is rough ER

Answer 3

60%

Question 4

% of liver hepatocyte membrane that is mitochondria inner membrane

Answer 4

32%

Question 5

3 topological categories of cell

Answer 5

1. Nucleus and cytosol
   - communication through nuclear pore complex
2. Organelles in secretory and endocrine pathway
   - ER, golgi, endosomes, lysosomes
3. Mitochondria

Question 6

What two compartments does the ER divide the cytoplasm in to

Answer 6

Luminal or cistern always compartment

Cytoplasmic or cytosolic compartment

Question 7

3 important functions of rough ER

Answer 7

1. Proteins modification and assembly
2. Segregation of proteins for intracellular use
3. Export proteins from the cell

Question 8

How do most proteins exit the rough ER and where do they go

Answer 8

In vesicles transported to the cis portion of the Golgi apparatus

Question 9

5 functions of smooth ER

Answer 9

1. Glycogen metabolism
2. Lipid and phospholipid synthesis
3. Detoxification
4. Steroidogenesis
5. Calcium regulation

Question 10

5 functions of the Golgi apparatus

Answer 10

1. Modification of carbohydrates attached to glycoproteins and proteoglycans
2. Polysaccharide and oligosaccharide synthesis
3. Synthesis of sphingomyelin and glycosphingolipids
4. Sorting secretory products
5. Packaging and storing secretory products into secretory granules or vesicles

Question 11

When does the golgi disassemble and reassemble

Answer 11

Disassembles during mitosis/meiosis

Reassembles in interphase

Question 12

Clathrate coated vesicles

Answer 12

Vesicles are coated in clathrin; these vesicles are seen in the exocytosis/secretory and endocytosis pathway

Transport products from:
Golgi apparatus —> lysosomes

products from the exterior of the cell —> lysosomes

Question 13

COP-coated vesicles

Coat protein

Answer 13

Transport products:

Between stacks of the Golgi apparatus (COP 1)

ER —> Golgi apparatus (COP 2)

Question 14

2 important steps in the lysosomal sorting pathway

Answer 14

1. Phosphorylation of lysosomal enzymes

2. Binding of lysosomal enzymes to M6P receptor

Question 15

Primary lysosome

Answer 15

Storage site of lysosomal hydrolases

• no digestive enzymes
• homogenous
• inactive enzymes

Question 16

Secondary lysosomes

Answer 16

Engaged in a catalytic process

• digestive enzymes
• heterogenous
• active enzymes

Question 17

Important step in endosome maturation

Answer 17

Lower internal pH to 5.5

Question 18

Familial hypercholesterolemia

Answer 18

Mechanism of cholesterol uptake is disrupted; characterized by elevated LDL (predominant cholesterol transport protein in the plasma)

High levels of LDL lead to atherosclerotic plaques

Question 19

4 functions of peroxisomes (micro bodies)

Answer 19

1. Synthesis and degradation of H202
2. Beta oxidation of long chain FA
3. Bile acid and cholesterol synthesis
4. Detoxify alcohol

Question 20

Zellweger spectrum disorders

Answer 20

Peroxisome biogenesis disorders caused by defect in assembly of the peroxisome; normally causes death within first year of life

Question 21

What type of cells typically would have lots of rough ER

Answer 21

Cell that make secreted proteins

Question 22

Lysosomes contain enzymes that are most active when

• what do they do

Answer 22

At acidic pH

Break down proteins, carbs, lipids, nucleus acids