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Biology > transport across cell membranes > Flashcards

transport across cell membranes Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

Plasma membranes

A

Partically permeable which controls which substances can enter and leave the cell. They act as a barrier that can create a separate environment.

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2
Q

What organelles have a single membrane

A

Endoplasmic reticulum, golgi, lysosomes, vesicles and vacuoles

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3
Q

What organelles have a double membrane

A

Mitochondria, chlorplast and the nucleus

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4
Q

Arrangement of phospholipids

A

They are in a bilayer, they have integrated proteins, glycoproteins and glycolipids. Known and fluid mosaic model

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5
Q

the function of the phospholipid bilayer

A

forms a barrier to dissolved substances. its hydrophobic so doesn’t allow water through

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6
Q

function of intrinsic proteins

A

they allow large polar molecules into the membrane

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7
Q

glycoproteins

A

proteins with carbohydrate attached. they act as antigens.

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8
Q

glycolipids

A

lipids and a carbohydrate attached. act as antigens.

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9
Q

function of cholestrol

A

a type of lipid which fits between the phospholipids. gives stability. hydrophobic so is waterproof.

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10
Q

how does temperature affect the membrane

A

below zero degrees- thaws and ice crystals will pierce the membrane making it more permeable. intrinsic proteins denature.
0-45 degrees- more freely and membrane is partially permeable.
over 45 degrees- phospholipid starts to melt and membrane becomes more permeable.

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11
Q

how do solvents impacts membranes

A

they can insert themselves into bilayer. pushes the phospholipids out of their orderly placement and increases their movement.

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12
Q

how to know if membrane is more permeable

A

beetroot cells has red pigment in the vacuole. you know the membrane is more permeable as the water will turn red when boiled.

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13
Q

how to test for membrane permeability

A

colorimeter

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14
Q

how to used a colorimeter

A

select a filter which will maximise the accuracy of the experiment which is opposite to the colour tested on the colour wheel. to determine the concentration of unknown sample, use several solutions you know the concentration of. create a calibration curve. compare unknown with known samples.

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15
Q

what is diffusion

A

the net movement of molecules from an area of high concentration to an area of low concentration.

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16
Q

factors effecting simple diffusion

A

concentration gradient, membrane thickness, surface area, temperature.

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17
Q

how does concentration gradient effect diffusion

A

the greater the concentration gradient the fast the diffusion

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18
Q

how does membrane thickness effect diffusion

A

the thinner the membrane the faster the diffusion.

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19
Q

how does surface area effect diffusion

A

the larger the surface area the faster the rate of diffusion.

20
Q

how does temperature effect diffusion

A

the higher the temperature the faster the diffusion

21
Q

what is facilliated diffusion

A

larger molecules and polar molecules move through intrinsic proteins and through the membrane structure.

22
Q

factors affecting facilliated diffusion

A

concentration gradient, number of intrinsic proteins

23
Q

how does concentration gradient affect facilitated diffusion

A

the greater the concentration gradient the faster the diffusion

24
Q

how does the number of intrinsic proteins affect facilitated diffusion

A

the grater the number of intrinsic proteins the faster the diffusion

25
Q

what is osmosis

A

the diffusion of water molecules across a partially permeable membrane from a high concentration to a low concentration

26
Q

what is water concentration also know as

A

water potential

27
Q

types a water potential

A

the more negative the water potential the solutes it has in it. zero water potential is pure water.

28
Q

higher water potential in animal calls and plant cells

A

in animal cells the cell can become lysed and explode whereas in plant cells the cell becomes turgid was the cell wall prevents it from bursting

29
Q

isotonic solution in animal and plant cells

A

in animal cells the cell becomes normal and in plant cells the cell becomes flaccid

30
Q

lower water potential in animal and plant cells

A

in animal cells the cell becomes shrivelled and in plant cells the cells become plasmolyzed

31
Q

what factors effect the rate of osmosis

A

water potential, membrane thickness, surface area

32
Q

how does water potential affect osmosis

A

the higher the water potential gradient the faster the osmosis

33
Q

how does membrane thickness affect osmosis

A

the thicker the membrane the less osmosis

34
Q

how does surface area affect osmosis

A

the larger the surface area the faster the osmosis

35
Q

how to calculate the serial dilution

A

dilution factor= initial volume of the stock solution/ final solution volume

36
Q

sucrose practical

A

fill test tube with 10cm3 of the 2M sucrose solution. fill 5 test tubes with 5cm3 of distilled water. use a pipette to transfer 5cm3 of sucrose from the test tube of 5cm3 of water.

37
Q

what is active transport

A

moves molecules across a plasma membrane from a low concentration to a high concentration.

38
Q

what do cells which go through active transport have a lot of

A

the have a lot of mitochondria to produce ATP which gives energy to the cells to move molecules up the gradient.

39
Q

what is co transport

A

uses carrier proteins called co transporters. the bind 2 molecules together, one moves down the concentration gradient and the other is brought with it.

40
Q

best example of co transport

A

in the lumen of the ileum with sodium and glucose

41
Q

factors affecting active transport

A

speed of carrier proteins, number of carrier proteins, rate of respiration

42
Q

how does the speed of carrier proteins affect active transport

A

the faster they work the faster the rate of active transport

43
Q

how does the number of carrier proteins affect active transport

A

the more carrier proteins, the faster the rate of active transport

44
Q

how does the rate of respiration affect active transport

A

when there is more respiration there is more energy so a faster rate of active transport

45
Q

what is endocytosis

A

the process of capturing a substance or particle from outside the cell by engulfing it with the cell membrane.

46
Q

what is exocytosis

A

the process by which materials are removed from or transported out of the cells. packed into secretory vesicles formed by the Golgi body.

Biology (12 decks)

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