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Flashcards in Zaidi Deck (109)
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1

what is gated transport

between nucleus and cytosol through nuclear pore complexes (active transport and free diffusion)

2

what is transmembrane transport

membrane protein translators directly transport specific proteins from cytosol across an organelle membrane

3

what is vesicular transport

membrane enclosed transport intermediates move proteins between various compartments via vesicles

4

protein transfer/transport to various compartments guided by ______

sorting signals

5

describe sorting signals

stretch of amino acids, typically 15-60 residues long with localization on N or C terminus within protein sequence

6

multiple scattered sequences in protein may form ______

signal patch

7

what removes signal after protein reaches final destination?

signal peptidase

8

Signal sequences are both necessary and sufficient for what?

protein targeting

9

What are signal sequences recognized by?

complementary receptors

10

Describe nuclear transport

bidirectional, selective and gated

11

what are sorting signals called for nuclear?

nuclear localization sequence

12

nuclear localization sequences are rich in what amino acids?

lysine and arginine

13

what are nuclear pore complexes?

perforate nuclear envelope in eukaryotic cells which transports molecules in both directions, passive diffusion of small molecules and facilitated transport

14

transport of the nuclear pore complex is facilitated by the binding of particles to _____ extending from NPC

fibrils

15

what are nuclear localization signals (NLS)

sorting signals that direct molecules to nucleus, rich in lysine and arginine

16

look at nuclear import and export pictures

slide 9

17

the mitochondrial signal sequence is made up of _______ and _____ signal sequences

n terminal and internal

18

In the mitochondrial signal sequence specific receptor proteins recognize a configuration which is what?

positively charged residues cluster on one end and uncharged hydrophobic on the other end to form an amphiphilic alpha helix

19

review the translators in mitochondrial membrane slide

slide 12

20

Where is the tom complex located?

outer mitochondrial membrane

21

where is the Sam complex located

outer mitochondrial membrane

22

Where is the Tim22 and tim23 complexes located?

inner mitochondrial membrane

23

Where is the Oxa membrane complex located?

inner mitochondrial membrane

24

What does the TOM do?

import of all nuclear encoded proteins to insert them in the outer membrane

25

what does TIM 23 do?

transports soluble proteins into matrix and helps insert membrane proteins in inner membrane space

26

what does TIM 22 do?

mediates the insertion of a specific subclass of proteins

27

What are the two components of the tom and Tim complexes?

receptors for mitochondrial precursor proteins
translocation channels

28

What does the sam complex do?

translocates and inserts/folds beta barrel proteins in the outer membrane

29

What does the oxa complex do?

mediates insertion of all proteins synthesized in mitochondria. Also some proteins already present in matrix brought from outside

30

ER signal sequence guided to ER membrane by 2 components:

-signal recognition particle (SRP)
- SRP receptor