Cell biology V Flashcards

1
Q

Is vesicular transport selective or general?

A

Selective

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2
Q

What is the direction of transport for COP II?

A

Anterograde - from ER to Golgi

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3
Q

What is the direction of transport for COP I?

A

Retrograde - from Golgi to ER

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4
Q

What is the purpose of retrograde transport?

A

To return membrane, v-SNARE, and missorted proteins back to the ER

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5
Q

What are two examples of v-SNAREs?

A

Synaptotagmin and synaptophysin

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6
Q

What is the purpose of SNARE proteins?

A

Allow vesicle to recognize its target domain

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7
Q

What effect do the neurotoxins of tetanus and botulism have on SNAREs?

A

The toxins enter nerve terminals and proteolyse SNARE proteins, preventing vesicles containing neurotransmitters from docking with pre-synaptic membranes of the nerve cell

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8
Q

What effect do tetanus toxins have on neurons?

A

Enter inhibitory neurons, proteolyse SNAREs, and release brake on the neuron

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9
Q

Are mitochondria acidophilic or basophilic?

A

Acidophilic

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10
Q

Define pleomorphic

A

Ovoid or threadlike structures - motile and can change shape

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11
Q

What is the diameter of a typical mitochondrion?

A

0.5 - 1 um

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12
Q

How many mitochondria are there in erythrocytes?

A

None

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13
Q

What is the lifespan of a typical mmitochondrion?

A

10 days

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14
Q

How do mitochondria reproduce?

A

Fission (can also fuse with each other)

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15
Q

Which mitochondrial membrane is selectively permeable?

A

Inner mitochondrial membrane

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16
Q

Which molecule is responsible for the decreased permeability of the inner mitochondrial membrane?

A

Cardiolipin

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17
Q

The cristae of mitochondria are shelf-like in what cell type?

A

Hepatocytes, cardiac, and muscle cells

18
Q

The cristae of mitochondria are tubular in what cell type?

A

Steroid-secreting cells

19
Q

Does the morphology of cristae have an effect on mitochondria function?

A

No

20
Q

What cellular processes occur in the mitochondrial matrix?

A

TCA cycle, fatty acid B-oxidation

21
Q

Which disease displays “parking lot inclusions” in affected mitochondria?

A

Myoclonic epilepsy with ragged red fibers (MERRF)

22
Q

What does catalase do?

A

Enzymatically forms water and oxygen from hydrogen peroxide

23
Q

Where does plasmalogen synthesis occur?

A

Peroxisome

24
Q

Where are peroxisomal enzymes synthesized?

A

Cytoplasm

25
Q

What causes Zellweger syndrome?

A

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

26
Q

What happens to peroxisome levels during chronic administration of antilipidemics?

A

Increase

27
Q

What process in nerve cells is impaired due to defective plasmalogen synthesis?

A

Myelination

28
Q

What are the components of the cytoskeleton?

A

1) Microtubules2) Microfilaments3) Thick filaments4) Intermediate filaments

29
Q

What is the diameter of microtubules?

A

24 nm

30
Q

How many longitudinally arranged protofilaments make up a microtubule?

A

13

31
Q

What makes up the protofilaments of microtubules?

A

Tubulin dimer subunits

32
Q

What cofactors are required for microtubule synthesis?

A

1) GTP2) Mg ions

33
Q

What role does gamma-tubulin have in microtubule synthesis?

A

Microtubules polymerize from a ring of gamma-tubulin

34
Q

What drugs inhibit polymerization of microtubules?

A

1) Colchicine2) Vinblastine3) Vincristine

35
Q

What drug inhibits depolymerization of microtubules?

A

Taxol

36
Q

What are the functions of microtubules?

A

1) Structural support of cytoplasm2) Organelle support3) Cell division4) Motility of cilia and flagella5) Long-range transport of vesicles via motor proteins

37
Q

What is the function of kinesin?

A

Long-range transport of vesicles toward the periphery

38
Q

A defect in kinesin has been shown to decrease the transport of receptors for what hormone?

A

Serotonin

39
Q

What is the function of dynein?

A

Long-range transport of vesicles toward the nucleus

40
Q

What molecule is responsible for long-range transport of vesicles toward the periphery of the cell?

A

Kinesin

41
Q

What molecule is responsible for long-range transport of vesicles toward the nucleus?

A

Dynein