Cell Bio: Organelles (Week 1) Flashcards Preview

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Flashcards in Cell Bio: Organelles (Week 1) Deck (9):
1

What must be present on a protein in order to gain entry into the nucleus?

Nuclear localization signal

* is 4-8 a.a. long; contains arginine, lysine, proline

2

What two CDK/cyclin pairs are responsible for G1--> S?

1. Cyclin D + CDK4 (phosphorylates RB--> frees E2F, allowing transcription of elements needed for synthesis)
2. Cyclin E + CDK2 (allows progression through G1/S checkpoint)

3

What two CDK/cyclin pairs are needed for progression from G2--> M?

1. Cyclin A + CDK2 --> mitotic prophase
2. Cyclin B + CDK1--> breakdown of the nuclear envelope

4

What molecule added to golgi directs proteins to the lysosomes?

Mannose-6-phosphate

5

What dz results from deficiency of mannose-6 phosphate?

I-cell disease--> corneal clouding, coarse facies, restricted joint movmement; death by age 8
*lysosomes swell with undigested materials, b/c lysosomal enzymes cant make in into the lysosomes

6

What residues are N-oligosaccharides added to in the golgi?

Asparagine

7

What residues are O-oligosaccharides added to in the golgi?

Serine and threonine

8

Other than beta oxidation of long chain fatty acids and brached amino acids, what other two important things occur in peroxisomes?

1. Synthesis of plasmalogens--> important phospholipids found in myelin
2. Oxidases and catalase for metabolizing ethanol and other toxic substances.

9

What enzyme deficiency leads to inability to make mannose-6 phosphate in I-cell disease?

Phosphotranseferase--> required for mannose-6 phosphate production

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