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bio > module 2.5 mr hill > Flashcards

module 2.5 mr hill Flashcards

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Biology 101 flashcards
1
Q

what are the 5 reasons why plasma membranes are essential

A

1-partially permeable (to allow particles to pass)
2-signalling to other cells
3-compartmenalizing organelles (forms a boundary of an organelle)
4-allows electrical signals to pass
5-provide attachment sites for enzymes etc…

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2
Q

draw the most basic structure ever of a plasma membrane

A

========== (double membrane)

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3
Q

what is the plasma membrane made out of

A

phospholipids

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4
Q

what is the glycocalyx

A

the combined layer of glycolipids and glycoproteins - carbohydrate groups on the exterior

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5
Q

what are glycoproteins

A

proteins with carbohydrates attached

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6
Q

what are glycolipids

A

lipids with carbohydrates attached

-phospholipid or lipid with chains of carbohydrate molecules

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7
Q

what is the plasma membrane held together by and what does this allow for

A

held by cholesterol-> maintains membrane fluidity

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8
Q

what are the 6 factors that affect rate of diffusion

A

temp, distance travelled, pressure, ph, conc., sa

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9
Q

what is equilibrium?

A

situations where concentrations are balanced and no net movement.

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10
Q

what’s a biological example of diffusion

A

gas exchange

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11
Q

what is diffusion

A

the net movement of molecules/substances from a high conc to a low conc down a concentration gradient

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12
Q

what can rapidly diffuse across a cell membrane

A

small non-polar molecules e.g C02 and O2

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13
Q

talk about facilitated diffusion

A
  • charged particles (ions) cannot diffuse across a membrane, even if they are very small.
    -if the molecule is to large or charged to diffuse across on its own…
    it can diffuse if there is a specific transport protein (channel)
    -with an addition of a protein that helps it out if the molecule is large, charged or both.
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14
Q

what are the two types of proteins (pm)

A

channel proteins and carrier proteins

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15
Q

channel proteins -state 2 points abt them

A
  • form pores in the membrane

- many only let 1 type of molecule through

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16
Q

carrier proteins -state 2 points abt them

A
  • molecules fit in at membrane +specific molecule fits into carrier e.g glucose
  • protein changes shape to pass molecule through
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17
Q

solute?

A

any substance dissolved in a solvent

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18
Q

solvent?

A

any fluid which can dissolve a solute

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19
Q

solution?

A

A liquid that consists of a dissolved solute in a solvent

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20
Q

what’s osmosis

A

osmosis is the net movement/diffusion of water. it is the movement of water molecules from a region of high water potential to a region of low water potential, through a partially- permeable membrane.

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21
Q

water potential?

A

the tendency for water to move(diffuse). unit= kPa

22
Q

hypotonic?

A

higher water potential outside the cell (water moves in)

23
Q

hypertonic?

A

lower water potential outside the cell (water moves out the cell)

24
Q

what happens when water moves into plant cell via osmosis

A

membrane pushes against wall.

TURGID

25
Q

what happens when water moves into animal cell via osmosis

A

animal cell bursts open

CYTOLISED

26
Q

what happens when water moves out plant cell

A

cell membrane pulls away from cell wall as water leaves.
the cell is PLASMOLYSED
-the tissue becomes FLACID

27
Q

what happens when water moves out animal cell

A

animal cell shrinks and appears wrinkled

the cell is CRENATED

28
Q

what is active transport used to do

A

used to move molecules and ions across a membrane against their concentration gradient

29
Q

what does active transport require

A
  • transport proteins( carrier proteins) (which require ATP to function)
30
Q

what do transport proteins use ATP to make

A

to make a conformational change (change shape) to allow molecules to pass.

31
Q

what 4 processes is active transport used in

A
  • uptake of glucose and amino acids in the small intestine
  • absorption of mineral ions by plant roots
  • excretion of hydrogen ions and urea by kidneys
  • excretion of sodium and potassium ions in neurones and muscle cells
32
Q

what do cells that undertake active transport on a large scale have a lot of

A

many mitochondria

33
Q

when is bulk transport used

A

when extremely large substances need to be moved across a cell membrane

34
Q

what are the 2 types of bulk transport and what do they involve

A

endocytosis and exocytosis (both involve changes to membrane shape)

35
Q

what is exocytosis

A

movement of volume out of cell

-vesicles fuse with plasma membrane and contents are released

36
Q

what is endocytosis

A

bulk transport of material into a cell

37
Q

what are the two processes within endocytosis

A

phagocytosis and pinocytosis

38
Q

endocytosis: what’s phagocytosis

A

engulfing of SOLIDS

uses pseudopodia to surround and engulf target

39
Q

endocytosis: what’s pinocytosis

A
  • engulfing of LIQUIDS
40
Q

what are examples of proteins that could be attached to carrier proteins

A

function as:

  • enzymes
  • antigens
  • receptor sites for complimentary shaped signalling chemicals such as hormones
41
Q

in neurones (nerve cells), what do the channel proteins and carrier proteins allow for

A

-entry and exit of ions to bring about the conduction of electrical impulses along their length.

42
Q

what is the myelin sheath wrapped around in a neurone

A

its wrapped around the axon

43
Q

what does the plasma membrane of white blood cells contain

A

special protein receptors that enable them to recognise the antigens on foreign cells.

44
Q

what do root hair cells have many of

A
  • many carrier proteins to actively transport nitrate ions from soil to roots
45
Q

can fat-soluble molecules such as steroid hormones diffuse across the lipid bilayer

A

-yes as they can dissolve in the lipid bilayer (dont need a channel protein)

46
Q

what specific water channels allow water to move across cell membrane

A

-specific channel proteins called aquaporins

47
Q

how is conc across a cell membrane obtained?

A
  • many molecules entering the cells then pass into organelles and are used for metabolic reactions
    (o2 for mitochondria and co2 for chloroplasts)
48
Q

5 factors that affect rate of simple diffusion

A
  • temperature ( more k energy)
  • diffusion distance (thicker membrane=slower)
  • sa (more diffusion can take place across a larger sa)
  • size of diffusing molecules
  • conc gradient
49
Q

how is glucose moved through phospholipid bilayer

A

via a transmembrane carrier protein (its a large molecule)

50
Q

what do neurone plasma membranes have many channels specific for

A

-sodium ions or potassium ions

51
Q

what do epithelial cells have many channels specific for

A

-chloride ions

bio (29 decks)

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