Slide 30 (Answer) / 74 12 Which solute(s) will exhibit a net diffusion out of the cell? A sucrose environment Cell: 0.01M 0.05M B glucose sucrose sucrose 0.01M 0.02M C fructose Answer glucose glucose B 0.01M D sucrose, fructose glucose, and fructose E sucrose and [This object is a pull tab] glucose
Slide 31 / 74 13 When diffusion has occurred until there is no longer a concentration gradient, then _______________ has been reached. A equilibrium B selective permeability C phospholipid bilayer D homeostasis
Slide 31 (Answer) / 74 13 When diffusion has occurred until there is no longer a concentration gradient, then _______________ has been reached. A equilibrium B selective permeability Answer A C phospholipid bilayer D homeostasis [This object is a pull tab]
Slide 32 / 74 14 When equilibrium is reached, what is the concentration of fructose outside the cell? environment Cell: 0.01M 0.05M sucrose sucrose 0.01M 0.02M glucose glucose 0.01M fructose
Slide 32 (Answer) / 74 14 When equilibrium is reached, what is the concentration of fructose outside the cell? environment Cell: 0.01M 0.05M sucrose sucrose Answer 0.01M 0.02M 0.005M glucose glucose 0.01M fructose [This object is a pull tab]
Slide 33 / 74 Osmosis Return to Table of Contents
Slide 34 / 74 Osmosis Osmosis is the diffusion of free water molecules across a selectively permeable membrane.
Slide 35 / 74 Two ways to Describe Osmosis The water is moving with its concentration gradient from an area with lots of free water molecules to an area with fewer free water molecules. OR The water moves from areas of low solute concentration to areas of high solute concentration until the solute concentrations are in equilibrium.
Slide 36 / 74 Osmosis solute molecule water molecule If the solution on the outside of H 2 O the membrane has a higher solute concentration than the solution inside, we say that the outside solution is hypertonic. This means that water will diffuse from the inside solution to the outside solution.
Slide 37 / 74 Osmosis If too much water leaves the cell, due to its being in a hypertonic solution, it can shrink or shrivel up. solute molecule water molecule H 2 O
Slide 38 / 74 Osmosis If the solution on the outside of the membrane has a lower solute concentration than the solution inside the membrane we say that the outside solution is hypotonic. This means that water will diffuse from the outside solution to the inside solution. solute molecule water molecule H 2 O
Slide 39 / 74 Osmosis solute molecule water molecule If too much water enters a cell due to its being in a hypotonic solution it can swell, and if it swells too much H 2 O it can _________, or burst.
Slide 40 / 74 Osmosis solute molecule water molecule If the solution on the outside of the membrane has an equal solute concentration to the H 2 O solution inside the membrane we say that the outside solution is isotonic to the inside solution. This means that water will diffuse equally across the membrane in either direction.
Slide 41 / 74 15 The diffusion of water molecules across a selectively permeable membrane is called what? A diffusion isotonic B C osmosis D hypotonic
Slide 41 (Answer) / 74 15 The diffusion of water molecules across a selectively permeable membrane is called what? A diffusion Answer isotonic B C C osmosis D hypotonic [This object is a pull tab]
Slide 42 / 74 16 Water molecules diffuse from inside the plasma membrane to outside only A outside the plasma membrane to inside only B from areas of high solute concentration to C areas of low solute concentration from areas of low solute concentration to D areas of high solute concentration
Slide 42 (Answer) / 74 16 Water molecules diffuse from inside the plasma membrane to outside only A outside the plasma membrane to inside only B from areas of high solute concentration to C areas of low solute concentration from areas of low solute concentration to Answer D areas of high solute concentration D [This object is a pull tab]
Slide 43 / 74 17 Diffusion and osmosis are both types of active transport. True False
Slide 43 (Answer) / 74 17 Diffusion and osmosis are both types of active transport. True False Answer FALSE [This object is a pull tab]
Slide 44 / 74 18 What type of environment has a higher concentration of solutes outside the plasma membrane than inside the plasma membrane? A hypertonic B isotonic C normal D hypotonic
Slide 44 (Answer) / 74 18 What type of environment has a higher concentration of solutes outside the plasma membrane than inside the plasma membrane? A hypertonic B isotonic Answer C normal A D hypotonic [This object is a pull tab]
Slide 45 / 74 19 What type of environment has an equal amount of solute on the inside and outside of the plasma membrane? A hypertonic B isotonic C normal D hypotonic
Slide 45 (Answer) / 74 19 What type of environment has an equal amount of solute on the inside and outside of the plasma membrane? A hypertonic B isotonic Answer C normal B D hypotonic [This object is a pull tab]
Slide 46 / 74 20 What type of solution has a greater flow of water to the inside of the plasma membrane? A hypertonic B isotonic C normal D hypotonic
Slide 46 (Answer) / 74 20 What type of solution has a greater flow of water to the inside of the plasma membrane? A hypertonic B isotonic Answer C normal D D hypotonic [This object is a pull tab]
Slide 47 / 74 21 The membrane is permeable to water and to the simple sugars glucose and fructose but completely impermeable to the sucrose. Is the solution outside the cell isotonic, hypotonic, or hypertonic? A Hypertonic environment B Hypotonic 0.02M sucrose C Isotonic Cell: 0.04M 0.03M glucose sucrose 0.01M 0.03M fructose glucose
Slide 47 (Answer) / 74 21 The membrane is permeable to water and to the simple sugars glucose and fructose but completely impermeable to the sucrose. Is the solution outside the cell isotonic, hypotonic, or hypertonic? A Hypertonic environment B Hypotonic 0.02M sucrose C Isotonic Cell: 0.04M 0.03M glucose sucrose 0.01M Answer 0.03M fructose A glucose [This object is a pull tab]
Slide 48 / 74 22 In which direction will there be a net osmotic movement of water? In A Out B No net osmosis C environment Cell: 0.02M sucrose 0.05M sucrose 0.04M glucose 0.03M glucose 0.01M fructose
Slide 48 (Answer) / 74 22 In which direction will there be a net osmotic movement of water? In A Out B No net osmosis C Answer A environment Cell: 0.02M sucrose 0.05M sucrose 0.04M glucose 0.03M glucose 0.01M fructose [This object is a pull tab]
Slide 49 / 74 Plasma Membrane of Cells, Transport through Proteins Return to Table of Contents
Slide 50 / 74 Plasma Membrane of Cells Early cells were simple lipid bilayers, relying only on passive transport. Later cells developed more complex membranes that included proteins. These proteins act as doorways to allow for more molecules to enter and leave the cell. Most small molecules can diffuse without membrane proteins. Larger molecules need to be facilitated (helped) to diffuse across a membrane by these proteins.
Slide 51 / 74 Phospholipid Bilayer Remember that membranes are made up mostly of phospholipids. Phospholipids are __________________ molecules, containing hydrophobic and hydrophilic regions.
Slide 52 / 74 2 Types of Membrane Proteins The plasma membrane also contains two types of proteins: Peripheral proteins are not embedded in the membrane, but instead stay on only one side of the membrane. Integral proteins pass through the hydrophobic core and often span the membrane from one end to the other, also called transmembrane proteins.
Slide 53 / 74 Fluid Mosaic The plasma membrane is sometimes referred to as a fluid mosaic. Fluid because the phospholipids can move sideways within the membrane and do not stay in one stationary position. Proteins can also move around in the membrane but they are much larger than lipids and move more slowly.
Slide 54 / 74 Fluid Mosaic The plasma membrane is sometimes referred to as a fluid mosaic. Mosaic means the membrane contains many different proteins spread throughout.
Slide 55 / 74 23 Which of the following statements about the role of phospholipids in forming membranes is correct? A They are completely insoluble in water. B They form a single sheet in water. They form a structure in which the hydrophobic C portion faces outward. D They form a selectively permeable structure.
Slide 55 (Answer) / 74 23 Which of the following statements about the role of phospholipids in forming membranes is correct? A They are completely insoluble in water. B They form a single sheet in water. They form a structure in which the hydrophobic Answer C portion faces outward. D D They form a selectively permeable structure. [This object is a pull tab]
Slide 56 / 74 24 Which best describes the structure of a cell's plasma membrane? A proteins sandwiched betweeen two layers of phospholipids B proteins embedded in two layers of phospholipids C phospholipids sandwiched between two layers of proteins D a layer of protein coating two layers of phospholipids
Slide 56 (Answer) / 74 24 Which best describes the structure of a cell's plasma membrane? A proteins sandwiched betweeen two layers of phospholipids B proteins embedded in two layers of phospholipids Answer C phospholipids sandwiched between two layers of B proteins D a layer of protein coating two layers of phospholipids [This object is a pull tab]
Slide 57 / 74 25 The fluid-mosaic model of membrane structure refers to _____. the fluidity of phospholipids and the pattern of A proteins in the membrane the fluidity of proteins and the pattern of phospholipids B in the membrane C the ability of proteins to switch sides in the membranes the fluidity of hydrophobic regions, proteins, and the D mosaic pattern of hydrophillic regions
Slide 57 (Answer) / 74 25 The fluid-mosaic model of membrane structure refers to _____. the fluidity of phospholipids and the pattern of A proteins in the membrane the fluidity of proteins and the pattern of phospholipids B in the membrane Answer C the ability of proteins to switch sides in the membranes A the fluidity of hydrophobic regions, proteins, and the D mosaic pattern of hydrophillic regions [This object is a pull tab]
Slide 58 / 74 Membrane Protein Functions Proteins serve several important functions in the cell membrane. Transport Signal transduction Cell-cell recognition Enzymatic activity
Slide 59 / 74 Transport Proteins can act as doorways for nutrients and waste. There are two types of transport which require proteins: · Facilitated Diffusion (a type of passive transport) · Active Transport (requires energy)
Slide 60 / 74 Facilitated Diffusion Small molecules like O 2 and CO 2 readily diffuse through all plasma membranes because they are small and non-polar; they can squeeze between the phospholipids. However...... Larger molecules and ions, charged particles, cannot squeeze between the phospholipids, they need the help of a transport protein. This is called Facilitated Diffusion .
Slide 61 / 74 Facilitated Diffusion Just like regular diffusion, particles in Facilitated Diffusion move from an area of high to low concentration. Unlike regular diffusion these particles move through the membrane with the help of a integral protein. Since the substances are going with their concentration gradient, this is a type of Passive Transport: no energy is needed.
Slide 62 / 74 Examples of Transport Proteins Channel proteins are one type of transmembrane transport protein that provide corridors that allow a specific molecule or ion to cross the membrane. Carrier proteins are another type of transmembrane transport protein that change shape slightly when a specific molecule binds to it in order to help move that molecule across the membrane.
Slide 63 / 74 Examples of Transport Proteins
Slide 64 / 74 26 Which of the following molecules is most likely to diffuse freely across the lipid bilayer of the plasma membrane without the involvement of a transport protein? A carbon dioxide B glucose C sodium ion D DNA E all of the above
Slide 64 (Answer) / 74 26 Which of the following molecules is most likely to diffuse freely across the lipid bilayer of the plasma membrane without the involvement of a transport protein? A carbon dioxide Answer B glucose A C sodium ion D DNA E all of the above [This object is a pull tab]
Slide 65 / 74 27 Which of the following processes includes all others? A osmosis B diffusion of a solute across a membrane C facilitated diffusion D passive transport
Slide 65 (Answer) / 74 27 Which of the following processes includes all others? A osmosis B diffusion of a solute across a membrane Answer C facilitated diffusion D D passive transport [This object is a pull tab]
Slide 66 / 74 28 Facilitated diffusion moves molecules _____. A against their concentration gradients using energy against their concentration gradients without the B use of energy C with their concentration gradients using energy D with their concentration gradients without the use of energy
Slide 66 (Answer) / 74 28 Facilitated diffusion moves molecules _____. A against their concentration gradients using energy against their concentration gradients without the B use of energy C with their concentration gradients using energy Answer D D with their concentration gradients without the use of energy [This object is a pull tab]
Slide 67 / 74 29 Carrier proteins are an example of integral proteins. True False
Slide 67 (Answer) / 74 29 Carrier proteins are an example of integral proteins. True False Answer TRUE [This object is a pull tab]
Slide 68 / 74 Active Transport Active Transport uses energy to move solutes through a transport protein against their concentration gradients. Carrier proteins can be used in active transport for specific molecules. energy
Slide 69 / 74 Comparing Facilitated Diffusion and ActiveTransport Passive Active Transport Transport (REQUIRES ENERGY) Click here for a comparison of the different forms of membrane transport
Slide 70 / 74 30 Which one of the following is not in some way involved in facilitated diffusion? A a concentration gradient B a membrane C a protein D an energy source E all of the above are components of facilitated diffusion
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