DSA 1: Cell Organelles

Question 1

What is the role of the plasma membrane?

Answer 1

Outer bilayer of cells

• protective
• transporters
• signaling

Question 2

What is the role of the nucleus?

Answer 2

Contains genome

-principal site for DNA and RNA synthesis

Question 3

What is the role of the cytoplasm?

Answer 3

Intermediary Metabolism

Question 4

What is the role of the endoplasmic reticulum?

Answer 4

Rough ER

• protein synthesis and folding
• segregation of proteins for intracellular use
• export from cell

Smother ER

• lipid synthesis
• glycogen metabolism
• phospholipid synthesis
• detoxifcation
• steroidogenesis
• calcium regulation

Question 5

What is the role of the golgi apparatus?

Answer 5

Post translational changes on proteins and lipids

• attach carbohydrates to glycoproteins and proteoglycans
• polysaccharide and oligosaccharide synthesis

Question 6

What is the role of the mitochondria?

Answer 6

POWERHOUSE OF THE CELL

-ATP production, signaling, cell differentiation and cell death

Question 7

What is the role of the lysosome?

Answer 7

Digestive enzymes that degrade organelles and biomolecules

-acidic

Question 8

What is the role of the peroxisomes?

Answer 8

Has enzymes for oxidation reactions

• synthesis and degradation of hydrogen peroxide
• B oxidation of long chain fatty acids
• bile acids and cholesterol synthesis
• detoxify alcohol

Question 9

How does the lumen of cellular compartments communicate with each other and the exterior of the cell?

Answer 9

Membrane budding and fusion

Question 10

What does the ER consist of?

Answer 10

Flat sacs (cisternae)
Tubules
Vesicles

Lumen/Cisternal compartment
Cytoplasmic/Cytosolic compartment

Question 11

Where are proteins from Rough ER transported to?

Answer 11

Cis portion of Golgi apparatus

Question 12

What is the difference between smooth and rough ER?

Answer 12

Smooth ER Lacks:
-ribosomes-
tubular cisternae

Question 13

Where does the cis and trans side of Golgi Apparatus face?

Answer 13

cis: adjacent to ER
trans: toward plasma membrane and nucleus

Question 14

What are the two types of vesicle transport mechanisms?

Answer 14

Clathrin Coated
-transport from golgi apparatus to lysosomes or products from exterior of cell to lysosome

COP coated vesicles
transport from Golgi and ER

Question 15

What surrounds invaginated coated pit in clathrin coated vesicles?

Answer 15

Dynamin

Question 16

What is the lysosomal sorting pathway?

Answer 16

1. Synthesis of lysosomal enzymes
2. Phosphorylation of lysosomal enzymes by M6-P
   - IMPORTANT
3. Inter-golgi transporting vesicles
4. Binding of lysosomal enzymes to M6P receptor
   - IMPORTANT
5. Clathrin-coated transporting vesicles
6. Clathrin coat is lost

Question 17

What is difference between primary and secondary lysosomes?

Answer 17

Primary: Storage site of lysosomal hydrolases

• No digestive events
• Homogeneous
• Inactive Enzymes

Secondary: Engaged in catalytic processes

• Digestive Enzymes
• Heterogenous
• Active Enzymes

Question 18

What are the 3 pathways for intracellular degradation?

Answer 18

Phagocytosis
Autophagy
Receptor-mediated endocytosis

Question 19

What is familial hypercholesterolemia?

Answer 19

Elevation of LDL

-gene encoding LDL receptor is mutated

Question 20

What are Zellweger spectrum disorders?

Answer 20

Peroxisome biogenesis disorders

-defects in assembly