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Flashcards in Cell V Deck (71):
1

What is vesicular transport?

a mechanism that uses membrane-bound structures, called transport vesicles, to ferry proteins from the donor compartment to the target membrane

2

How is vesicular transport selective (2)?

Transport vesicles must dock with correct target on membrane

Transport vesicle must package appropriate proteins for delivery

3

What is the protein that coats vesicles and directs them from the ER to the golgi?

COP II

4

What is the protein that coats vesicles, and directs the from the golgi back to the ER?

COP I

5

What is clatharin used for?

Coating incoming vesicles from the plasma membrane

Helps form secretory vesicles and directs to endosomes

6

What are the role of SNARE proteins?

allow the vesicle to recognize its target domain.

7

What are v-SNAREs?

SNARE proteins on vesicles

8

what are t-SNAREs?

SNARE proteins on target membranes

9

Why would you want to have equal flow of vesicles from the ER to the Golgi (3)?

1.Maintain membrane balance
2.Recycle SNAREs
3. Send back misdelivered proteins

10

How do the neurotoxins of tetanus and botulism exert their effects?

enter nerve terminals and proteolyse SNARE proteins

(This prevents vesicles containing neurotransmitters from docking with the pre-synaptic membrane of the nerve cell.

Tetanus toxins enter inhibitory neurons thereby releasing the braking effect on motoneurons)

11

Is the mitochondria acidophilic or basophilic?

Acidophilic

12

What are the only two organelles that have two membranes?

Nucleus and mitochondria

13

What does the term pleomorphic mean? Which organelle does it describe?

ovoid or elongated threadlike structures: are motile and change their shape

Mitochondria

14

How big are mitochondria?

0.5-1 um in length

15

What type of cells have numerous mitochondria?

Cells that have high metabolic activity

16

What are the striations of the plasmalemma? Where can these be seen?

Region

17

What is the characteristic feature that can by used to compare two mitochondria when trying to determine which one is more involved in energy metabolism?

Number of crista

18

What type of cell does not require mitochondria?

RBCs

19

What is the space that the cristie project?

Matrix

20

Which membrane is more selective the inner or outer mitochondiral membrane?

Inner

21

What is the length of the mitchondira?

10 um

22

How many mitochondria do lympocytes have (relatively)?

Few

23

How many mitochondria do hepatocytes have?

1000 (22% of total cell volume)

24

How many mitochondria do cardiac muscle cells have?

40% of cells volume

25

True or false: the number of mitochondira in muscle cells are relatively set and do not change unless as a part of a disease process

False--change with exercise vs sedentary lifestyle

26

True or false: mitochondira are easy to pick out via light microscopy due to their characteristic shape

False--very hard to see them at all with light microscopy unless you used tagged succinate dehydrogenase

27

What are the three components of mitochondira?

Proteins (mainly)
Lipids
RNA and mtDNA

28

Where are most of the mt proteins synthesized? What synthesizes them?

cytoplasm by free polyribosomes

29

About how long do mt last?

short time--some only 10 days

30

How do mts reproduce?

fission or fusion with one another.

31

What are the two outer mt membrane transporters?

TOM complex
SAM complex

32

What are the three inner mt membrane transporters?

TIM 23
TIM 22
OXA complex

33

What causes the decreased permeability of the inner mt membrane?

due to the presence of a high conc. of a phospholipid called cardiolipin

34

Why are mitochondria located next to the tuble in kidneys?

Support energy dependent ion gradient

35

Mitochondria in palisades confer what when stained?

Acidophilic striations

36

mt with tubular criste are involved in what process? What if they are shelf-like?

Cholesterol/steroid synthesis if tubular

ATP generation if shelf like

37

If you see a mitochondria with tubular cristae, what else are you likely to see in the cell nearby?

Deposits of lipids

38

Would you expect to find mitochondria with tubular or shelf-like cristae in hepatocytes?

Shelf-like

39

Would you expect to find mt with tubular or shelf-like cristae in Cardiac/skeltal muscle?

Shelf-like

40

Would you expect to find mt with tubular or shelf-like christae in steroid secreting cells?

Tubular

41

What is released from mitochondria to initiate apoptosis?

Cytochrome C

42

What is MERRF? HOw is it recognized?

At the electron microscopic level, affected mitochondria harbor “parking lot” inclusions. Mitochondria are also observed to assume peculiar shapes and cristal disruption.

43

What is the ping pong process of hormone synthesis?

Cholesterol go to mt to sER, back to mt, secreted

44

What are parking lot inclusions in mt that are seen at the EM level diagnostic of?

MERRF

45

Odd shape mt are diagnostic of what?

Substance abuse (like EtOH)

46

What are the five functions of peroxisomes?

Regulate H2O2
Kill pathogens
Oxidize EtOH
Plasmalogen
Beta FA oxidation

47

Zwellweger syndrome is the result of what?

impaired import of enzymes into the peroxisomes --no ether linkages in plamsa membrane lipids

48

True or false: cytoskeleton elements are considered to be organelles?

True

49

What are the three filaments?

Actin (thin)
Intermediate filaments
Myosin (thick)

50

What are microtubules made up of?

Tublin subunits

51

What are the structural elements that are hallow in cytoplasm?

Microtubules

52

What is Dynein?

ATPase attached to microtubules

53

What is the function of kinesin?

move vesicles on microtubule tracts frmo negative to positive end

54

Why is it important that microtubules are charged?

direct movement of vesicles

55

In what disease do lipids accumulate in the cerebellum?

Zellweger syndrome

56

How do peroxisomes get their enzymes?

From free polyribosome protein synthesis in the cytoplasm

57

What does the enzyme catalase do?

Forms water and oxygen from H2O2

58

True or false: Peroxisomal β-oxidation may equal that of mitochondria in some cell types.

True

59

How do peroxisomes maintain their phospholipid bilayer?

Phospholipid exchange proteins from sER maintain it

60

What is the defect that causes Zellweger syndrome?

Peroxisomal enzymes are not transported into the peroxisome. This is due to a defective import protein on the unit membrane of the peroxisome.

61

What are the four components of the cytoskeleton?

Microtubules
Actin (microfilaments)
Myosin (thick filaments)
Intermediate filaments

62

What is the diameter of microtubules?

24 nm

63

What is the composition of microtubules?

13 longitudinally arranged protofilaments made of tubulin dimers

64

What are the two molecules necessary for microtubule polymerization?

Mg ions and GTP

65

Where does microtubule synthesis occur?

From a ring of γ-tubulin within a microtubule-organizing center possessing many capping proteins.

66

What are three drugs that inhibit microtubule polymerization?

Colchicine, vinblastine, and vincristine

67

What is a drug that inhibits microtubule depolymerization?

Taxol

68

What is the function of inhibiting microtubule synthesis/depolymerization?

Anti-mitotic (CA)

69

What are the five major functions of microtubules?

1. Support cytoplasm
2. Organelle support
3. Cell division
4. Motility of cilia and flagella
5. Long range transport of vesicles by microtubule motor proteins

70

What are the two types of motor proteins used in microtubular transport? Which way does each move along the microtubule?

Kinesin -toward the periphery (neg to pos)

Dynein - toward the nucleus (positive to negative)

71

A sample of cells taken from a 5 mo show an accumulation of VLCFAs, and a biopsy of the cerebellum show lipdi deposits. What is your diagnosis?

Zellweger syndrome