2b- Cell membrane transport Flashcards

1
Q

in

A

Food
- carbohydrates
- sugars,
- proteins
- amino acids
- lipids
- salts
- O2
- H2O

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2
Q

out

A

Waste
- ammonia
- Salts
- CO2
- H2O products

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3
Q

Permeability of plasma membrane

A
  • Differentially (selectively) permable
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4
Q

Materials allowed to pass

A

Water, oxygen, carbon dioxide

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5
Q

prevents other from passing

A

Protein, Carbohydrates

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6
Q

Factors that determine how a substance may be transported across a plasma membrane:

A
  • Size
  • Polar or nonpolar
  • Charge
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7
Q
  • 2nd law of Themodynamics
  • governs biological systems
    – universe tends towards disorder (entropy)
A

Passive diffusion

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8
Q

movement from high to low concentration

A

Passive diffusion

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9
Q

Are the molecules are able to diffuse across a phospholipid bilayer at significant rates by using passive diffusion.

A

Only small, relatively hydrophobic

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10
Q

Gases

A
  • Oxygen
  • carbon dioxide
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11
Q

Water molecules

A
  • rate slow due to polarity
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12
Q

Lipid

A

Steroid Hormones

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13
Q

lipid soluble molecules

A
  • Hydrocarbons
  • alcohols
  • some vitamins
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14
Q

small nonecharged molecules

A
  • NH3
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15
Q

Why is diffusion important to cells and humans?

A
  • Cell respiration
  • Alveoli of lungs
  • Capillaries
  • Red Blood Cells
  • Medications: time
    release capsules
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16
Q

Diffusion through protein channels which do not interact with hydrophobic interior
- no energy needed

A

Facilitated diffusion

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17
Q

with help

A

facilitated

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18
Q

fast transportation

A

Open channel

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19
Q

two kinds of proteins

A
  • Carrier proteins
  • Channel proteins
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20
Q

bind specific molecules, undergo conformational change to release molecule

A

Carrier proteins

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21
Q

example of carrier protein

A

Glucose transporters

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22
Q
  • form open pores for free diffusion
  • found in gap junctions
A

Channel proteins

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23
Q

Molecules will randomly move through the pores in ____ ____

A

Channel proteins

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24
Q

do not extend through the membrane

A

Some carrier proteins

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25
Q

Other carrier proteins ____ ___ to move materials across the cell membrane

A

change shape

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26
Q

How do molecules move through the plasma membrane by facilitated diffusion?

A
  • Channel and Carrier proteins are specific:
  • Channel Proteins allow ions, small solutes, and water to pass
  • Carrier Proteins move glucose and amino acids
  • Facilitated diffusion is rate limited, by the number of
    proteins channels/carriers present in the membrane.
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27
Q
  • provide corridors allowing water molecules to cross the membrane.
  • Allow for fast transpor
  • water channels
  • protein pores used during osmosis
A

Aquaporins

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28
Q

is the diffusion of water across a differentially permeable membrane.

A

Osmosis

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29
Q

is the pressure that develops in a system due to osmosis.

A

Osmotic pressure

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30
Q

Different concentration

A

Hypertonic
Hypotonic
Isotonic

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31
Q

more solute, less water

A

Hypertonic

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32
Q

less solute, more water

A

Hypotonic

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33
Q

equal solute, equal wate

A

Isotonic

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34
Q
  • animal cell immersed in mild saltsolution
  • volume of cell is stable
  • no net movement of water
A

isotonic

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35
Q

a cell in fresh water
- Gains water, swell & can burst

A

Hypotonic

36
Q

plant cell in hypotonic

A

turgid

37
Q

a cell in salt water
- lose water and die

A

Hypertonic

38
Q

plant cells in hypertonic

A

Plasmolysis = wilt

39
Q

Water regulation in Paramecium

A

Contractile vacoule

40
Q

Examples of Osmosis in Cells and Humans

A

Cells:
- Removes water produce by cell respiration

Human:
- Large intestine cells transport water to bloodstream

  • Kidney cells form urine
41
Q

regulates the opening/closing of the channel

A

Member potential (voltage)

42
Q

permit the free passage of ions and small polar molecules through the outer membranes of bacteria.

A

Porins

43
Q

mediate the passage of ions across plasma membranes.

A

Ion channels

44
Q

channels open in response to the binding of neurotransmitters or other signaling molecules.

A

Ligand-gated

45
Q

channels open in response to changes in electric potential across the plasma membrane

A

Voltage-gated

46
Q

open or close depending on the presence or absence of a physical or chemical stimulus.

A

Gated channels

47
Q

Examples of voltage gated channels

A
  • K+ voltage-gated channels
  • Na+ voltage gated channels
48
Q

regulates opening/closing of the channel

A

Membrane potential

49
Q

exist as either open or close depending on the membrane voltage. It has only an activation gate.

A

K+ voltage-gated channels

50
Q
  • opens when the membrane potential depolarizes
  • It has activation and
    inactivation gates
A

Na+ voltage gated channels

51
Q

Cells may need to move molecules against concentration gradient
- costs energy = ATP

A

Active transport

52
Q

Importance active transport

A
  • Bring essential molecules
  • Rid cell of unwated molecules
  • Maintain internal conditions
53
Q

2 groups of active transport

A
  • Primary active transport
  • Secondary active transport
54
Q

Two substances are transported in the same direction across a
plasma membrane.

A

Symporter

55
Q

Two substances are transported across the membrane in opposite directions across the plasma membrane.

A

Antiporter

56
Q

transport only a single molecule using the facilitated diffusion of glucose.

A

Uniport

57
Q

uses active transport to move two molecules in opposite directions.

A

Antiport

58
Q
  • moving things out.
  • Transport of large molecules
A

Vesicle formation

59
Q

Substance transported in Exocytosis

A
  • Neurotransmitters
  • Hormones
  • Digestive enzymes
60
Q

Exocytosis of Proteins

A
  • Vesicle formation -> Golgi body -> ER
61
Q

Vesicles form as a way to transport molecules out of a cell

A

Exocytosis

62
Q

susbtance transported in exocytosis

A

Neurotransmitters, hormones and digestive enzymes.

63
Q

Vesicles form as a way to transport molecules
into a cell.

A

Endocytosis

64
Q

Types of endocytosis

A
  • Phagocytosis
  • Pinocytosis
  • Receptor mediated endocytosis
65
Q

Large,particulate matter (Bacteria, viruses, and aged or dead cells).

A

Phagocytosis

66
Q

Liquids and small particles dissolved in liquid

A

Pinocytosis

67
Q

Ligandreceptor complexes trigger infolding of a clathrin pit that forms a vesicle containing ligands

A

Receptor mediated endocytosis

68
Q

Substance/Products transported by Receptor mediated endocytosis

A
  • Some Vitamins
  • Certain Hormones
  • Antibodies
69
Q

Most common form of
endocytosis

A

Pinocytosis

70
Q

pinocytosis is also called

A

Cell drinking

71
Q

Examples of pinocytosis

A
  • Intestinal cells
  • Kidney cells
  • Plant root cells
72
Q

a form of pinocytosis, provides a mechanism for the selective uptake of specific macromolecules.

A

Receptor-mediated endocytosis

73
Q

Example of materials transported by Receptor mediated endocytosis

A
  • Uptake of cholesterol by animal cells

if with receptors in the surface
- Hormones, Cholesterol

74
Q

are specialized regions of the plasma membrane where specific cell surface receptors are found

A

Clathrin-coated pits

75
Q

a membrane associated GTP-binding protein, assists in the budding off of pits from the plasma membrane.

A

Dynamin

76
Q

Clathrin occupied space

A

About 1-2% of the surface area of plasma membranes

77
Q

What does clathrin formes

A

forming invaginated pits

78
Q

___ assembles into a ____ structure that ____ the membrane

A
  • Clathrin
  • basketlike
  • distorts
79
Q

located at the periphery of the cell, that fuse with clathrin-coated vesicles which have shed their coats

A

Endosomes

80
Q

Important features of early endosomes

A
  • Maintain acidic internal pH as the result of the action of a membrane H+ pump
81
Q

is the major fate of membrane proteins taken up by receptor-mediated endocytosis

A

Recycling to the plasma membrane

82
Q

is a phenomenon where receptor-ligand complexes are removed from the plasma membrane

A

Receptor-down regulation

83
Q

are phagosomes fused to lysosomes, contain lysosomal acid hydrolases that digest the ingested material

A

Phagolysosomes

84
Q

Does not move chloride ions causing sticky mucus to build up on the out side of the cell

A
  • Mutant CFTR channel
85
Q

moves chloride ions to the outside of the cell

A
  • Normal CFTR channel