3 Membrane Transport Flashcards Preview

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Flashcards in 3 Membrane Transport Deck (28)
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1
Q

can ions cross the plasma membrane freely?

A

no, they need a transporter

2
Q

what types of molecules can cross the PM freely?

A

hydrophobic, small molecules, O2, CO2, N2, benzene

3
Q

when a molecule crosses the membrane freely, down its gradient, what is this called?

A

simple diffusion

4
Q

when something is actively transnported, what is the key distinction between this and other transport?

A

ATP is being used (up a gradient)

5
Q

what type of trasnport does the glucose permease use?

A

facilitated diffusion: there is a confromation change after glucose binds, bringing it into the cell
-this is not coupled

6
Q

how does a symporter work? give a key example

A

one molecule goes down its gradient, deriving enough energy to push one molecule up its gradient - they are both going in the same direction though
-Na-glucose symporter

7
Q

how does an antiporter work? give an example

A
  • one molecule goes in, the other goes out, one is down its gradient, the other is up
  • Band 3 anion antiporter (anion exchanger)
8
Q

what is the exchange rate of the Na/K ATPase?

A

3 Na out for every 2 K in

9
Q

the CFTR is an example of what type of protein?

A

ABC transporter

10
Q

what is the signifigance of the MDR complex?

A

it pumps chemo drugs out of the cell and in cancer cells this can be upregulated, making them harder to treat

11
Q

P glycoprotein is aka what?

A

MDR complex, it is the transporter

12
Q

severe HDL deficiency in the plasma is characteristic of what disease?

A

tangiers

13
Q

accumulation of cholesterol ester in various tissues is characteristic of what disease? what does this lead to?

A

tangiers

-lymphadenopath, hepatosplenomegaly, peripheral neuropathy, and severe cardiovascular disease

14
Q

mutations in ABC-1 leads to what?

A

tangiers disease
-this ABC is responsible for the transport of cholesterol out of the cell. without cholesterol, HDL has nothing to pick up

15
Q

what is pinocytosis?

A

the cell sampling bits of the environment by taking in some of the cell membrane and engulfing some of the ECM in the process

16
Q

phagocytosis is mediated by what filament molecule?

A

actin

17
Q

virus particles and smaller particles are taken into the cell by what mechanism?

A

endocytosis

18
Q

bacteria and larger macromolecules are taken into the cell by what mechanism?

A

phagocytosis

19
Q

T/F phagocytosis is receptor mediated?

A

True

20
Q

toxoplasmosis/coccidiosis enters the cell via what mechanism?

A

phagocytosis

21
Q

walk through the endocytosis of LDL

A
  • LDL binds to LDL receptor
  • receptor and ligand are endocytosed
  • uncoating takes place via H pumps
  • receptor and ligan fuse with endosome
  • LDL is metabolized and cholesterol released into cell
  • LDL receptor buds off and is returned to the membrane
22
Q

what is the significance of familial hypocholesterolemia?

A

LDL receptor mediated endocytosis does not work and cells can not endocytose LDL to get cholesterol

23
Q

what is the significance of influenza and rabies with regard to RME?

A

the enter the cell via RME, fuse with the endosome, and then their genetic material is released into the cell to be replicated.

24
Q

what is the significance of leishmaniasis?

A

enters the cell via phagocytosis

25
Q

what is the significance of listeriosis?

A

phagocytosed

26
Q

what is the significance of TB?

A

phagocytosed

27
Q

what is the significance of streptococcus?

A

phagocytosed

28
Q

significance of mesothelioma?

A

filaments are phagocytosed, inhibiting the cell from dividing properly and leading to malignancies