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MED 103- BIOLOGY I > 24. PASSIVE TRANSPORT > Flashcards

24. PASSIVE TRANSPORT Flashcards

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1
Q
  1. What are the two types of transport of molecules through the plasma?
A
  1. active transport
  2. passive transport
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2
Q
  1. Which process usually allows for energy to be invested?
A
  • hydrolysis of ATP
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3
Q
  1. What is active transport?
A
  • it is the transport of a substance across a membrane
  • it requires energy investment
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4
Q
  1. What is Passive Transport?
A
  • it is the transport of a substance across a membrane
  • it has no energy investment
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5
Q
  1. What does Passive Transport result in?
A
  • it results in the equalisation of the concentration of a substance
  • this happens in both the internal and the external membrane region
  • this is known as dynamic equilibrium
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6
Q
  1. What are the two types of passive transport processes?
A
  1. Diffusion
  2. Osmosis
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7
Q
  1. What is Diffusion?
A
  • it is the movement of the solute molecules across the plasma membrane
  • they then move down their concentration gradient
    (they move from a high Sodium region to a low sodium
    region)
  • this is done until equilibrium is reached
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8
Q
  1. What is Osmosis?
A
  • it is the movement of solvent (water) molecules
  • across the plasma membrane
  • against the solute concentration gradient
    (this means that it moves from a low sodium area to a high sodium area)
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9
Q
  1. What are 4 qualities of moving from a low sodium region to a high sodium region?
A
  • there is more water present
  • there is less solute
  • there is less concentration
  • there is dilution
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10
Q
  1. How can small molecules diffuse?
A
  • they diffuse through the biological membranes
  • they do not require any help
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11
Q
  1. How can larger molecules and ions be diffused?
A
  • they need to be transferred
  • this is done by transport proteins
  • this is called Facilitated Diffusion
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12
Q
  1. What are two examples of transfer proteins?
A
  • ions channels
  • carrier proteins
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13
Q
  1. What can be said about Diffusion in terms of tendency?
A
  • it is the tendency for molecules of any substance to be spread out evenly
  • they do this into any available space
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14
Q
  1. What can be said about the molecules of dynamic equilibrium?
A
  • the same number of molecules is crossing one way
  • as is crossing in the other direction
  • this means there is equal molecule distribution
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15
Q
  1. Explain how the diffusion of one solute happens?
A
  • the membrane has pores that are large enough for the molecules of dye to pass through
  • the random movement of dye molecules will cause some of them to pass through the pores
  • this happens more often on the side with more molecules
  • the dye diffuses from the place where it is more concentrated
  • to the place where it is less concentrated
    (this is called diffusing down a concentration gradient)
  • this leads to a dynamic equilibrium
  • the solute molecules continue to cross the membrane
  • but they do it at equal rates in both directions
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16
Q
  1. Provide a definition for Diffusion in terms of concentration gradients?
A
  • the substances diffuse down their concentration gradient
  • they do this from the high concentration side to the low
    concentration side
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17
Q
  1. Provide a definition for the concentration gradient?
A
  • it is the difference in the concentration of a substance from one area to another
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18
Q
  1. Explain the process of the dilution of two solutes?
A
  • the solutions of two different dyes are separated by a membrane
  • this membrane is permeable to both dyes
  • each dye diffuses down its own concentration gradient
  • there will be a net diffusion of the purple dye towards the left
  • even though the total solute concentration was initially greater on the left side
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19
Q
  1. What are three qualities of facilitated diffusion?
A
  • the transport proteins speed up the movement of the molecules
    across the plasma membrane
  • it is a form of passive transport
  • this means that no energy is spent
  • the movement of the molecules is always down their concentration gradient
  • this is from a high solute concentration to a low solute concentration
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20
Q
  1. What are two examples of transport proteins?
A
  • channel proteins
  • carrier proteins
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21
Q
  1. What are Channel Proteins?
A
  • they are the channels that allow a specific molecule or ion to cross the membrane
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22
Q
  1. What are two examples of transport proteins?
A
  1. water channels
    (aquaporins)
  2. ion channels
    (gated)
    (they have a gate that opens as soon as it comes in
    contact with an ion)
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23
Q
  1. What are Carrier Proteins?
A
  • they bind to the solution
  • they undergo a change in shape
  • thus translocates the solute-binding site across the membrane
  • these proteins shuttle molecules across
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24
Q
  1. What is an example of a Carrier Protein?
A
  • a glucose transporter

(GLUT)

  • there are ten forms of it
25
Q
  1. What can diseases be caused by?
A
  • malfunctions in specific transport proteins
  • these are mutations in the gene of the protein
  • they are a mutated protein
26
Q
  1. What are two diseases that are caused by transport proteins malfunctions?
A
  1. Cystic Fibrosis
  2. Cystinuria
    (kidney disease)
27
Q
  1. What is the mutation that causes Cystic Fibrosis?
A
  • a mutation of the chloride ion channel protein
28
Q
  1. What are the effects of Cystic Fibrosis?
A
  • is leads to viscous secretions in the respiratory tract
  • this leads to pulmonary infections
29
Q
  1. What mutations causes Cystinuria?
A
  • the mutations of the renal membrane carrier protein
  • this happens in the kidney
30
Q
  1. What are the effects of Cystinuria?
A
  • it prevents the cysteine reabsorption into the blood
    (cysteine is an amino acid)
  • the cysteine the concentrates in the urine
  • kidney stones then form
  • these are forms of crystals
31
Q
  1. Provide a definition of Osmosis with regards to water?
A
  • it is the movement of the water across a semipermeable membrane
32
Q
  1. What is Osmosis affected by?
A
  • it is affected by the concentration gradient of the dissolved substances
  • these substances are known as the solute
33
Q
  1. With regards to Osmosis, in which direction does water move?
A
  • water moves from an area of lower solute and higher water concentration
    (a hypotonic condition)
  • to an area with a higher solute and a lower water concentration
    (a hypertonic condition)
34
Q
  1. What is the result of Osmosis?
A
  • the substance concentrations of the two areas become equal
  • equilibrium is reached
    (the concentrations are now isotonic)
35
Q
  1. When does Osmosis occur?
A
  • when the molecules/ions of a solute CANNOT pass through the plasma membrane
  • it becomes semi-permeable
  • there is no available transport molecule
36
Q
  1. Explain how the Osmosis of Sucrose Disaccharide happens?
A
  • the selectively permeable membrane does not allow sugar molecules to pass through the pores
  • it does allow the water molecules to pass through these pores
  • there is more free water molecules
  • the water concentration is higher
  • OSMOSIS THEN HAPPENS:
    - the water moves from an area of higher free water
    concentration
    - to an area of lower free water concentration
  • there are now fewer free water molecules in the solution
  • the water concentration is lower
  • the water molecules will cluster around the sugar molecules
37
Q
  1. What is Tonicity?
A
  • it is the ability of a solution to cause a cell to gain or to lose water
38
Q
  1. What does Tonicity depend on?
A
  • it depends on the concentration of the solutes that cannot penetrate the membrane
  • (EG: sucrose)
39
Q
  1. What does Tonicity have a large impact on?
A
  • it has a large impact on cells without walls
    (such as animal cells)
  • the cell walls protect cells against Osmotic Pressure
  • EG: plant and fungal cells
40
Q
  1. What are the three different types of Tonicities/Solutions?
A
  1. Isotonic Solution
    (equal solution)
  2. Hypertonic Solution
    (higher solution)
  3. Hypotonic Solution
    (lower solution)
41
Q
  1. What is an Isotonic Solution?
A
  • it is when the concentration of the solutes in the solution is the same as it is inside the cell
  • there will be no net movement of water
42
Q
  1. What is a Hypertonic Solution?
A
  • it is when the concentration of the solutes in the solution is greater than it is inside the cell
  • the cell will lose water
43
Q
  1. What is a Hypotonic Solution?
A
  • it is when the concentration of the solutes in the solution is less than it is inside the cell
  • the cell will gain water
  • this is to dilute the solute inside the cell
44
Q
  1. What is Osmoregulation?
A
  • it is the control of water balance
  • it is a cell property that relates to homeostasis
45
Q
  1. Which organisms have special adaptations for osmoregulation?
A
  • animals
  • other organisms without cell walls
  • these organisms live in either:
    - hypertonic environments
    - hypotonic environments
46
Q
  1. In which condition are cells without cell walls happier?
A
  • in isotonic solutions
47
Q
  1. What happens to animal cells in Hypotonic solutions?
A
  • they absorb too much water (H2O)
  • they become lysed
  • they expand
  • they can burst
  • they then die
48
Q
  1. What happens to animal cells in Isotonic Solutions?
A
  • there is an equal amount of water within the cell
    as there is in the environment surrounding the cell
  • there is no loss or absorption of water
  • the cell remains normal
  • and in desirable condition
49
Q
  1. What happens to animal cells in Hypertonic solutions?
A
  • they lose water
  • they become shrivelled
  • they shrink
  • they can die if these conditions persist
  • this condition is lethal upon prolonged exposure
  • or they can bounce back to their original condition if they
    are placed in water for a sufficient period of time
50
Q
  1. Where does the protist Paramecium usually live?
A
  • it lives in a hypotonic pond water environment
51
Q
  1. What feature does Paramecium have that allows it to act as a water pump?
A
  • it has a contractile vacuole
52
Q
  1. What are the two types of Paramecium Contractile Vacuoles?
A
  • filling vacuole
  • contracting vacuole
53
Q
  1. What does the filling vacuole of the Paramecium do?
A
  • it fills with fluid that enters from a system
  • this system has canals
  • these radiate throughout the cytoplasm
54
Q
  1. What does the contracting vacuole of the Paramecium do?
A
  • when the contractile vacuole is full:
    - the vacuole contracts
    - the canals contract
    - this expels fluid from the cell
55
Q
  1. What helps to maintain water balance?
A
  • cell walls
56
Q
  1. Name four organisms that have cell walls?
A
  1. Plant Cells
  2. Prokaryotes
  3. Fungi
  4. Algae
57
Q
  1. What happens to plant cells in a hypotonic environment?
A
  • they absorb the water from their surroundings
  • they become firm
    (turgid)
  • they are happiest in this environment
  • it leaves them in a healthy state
  • this is there optimum (normal) state
58
Q
  1. What happens to plant cells in an Isotonic environment?
A
  • they cannot uptake any water from the surroundings
  • the cell has a balance between the water in the cell and with water surrounding the cell
  • they become flaccid and limp
59
Q
  1. What happens to plant cells in a Hypertonic environment?
A
  • they will lose water
  • this environment leads to plasmolysis
  • they can get plasmolyzed
  • this means that they cell membrane will shrink
  • it will then detach from the cell wall
  • this is lethal for the plant cell

MED 103- BIOLOGY I (53 decks)

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