Cell Bio: Organelles (Week 1) Flashcards Preview

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

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


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)


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


What molecule added to golgi directs proteins to the lysosomes?



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


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



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

Serine and threonine


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.


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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