Cell Membrane (chapter 7)
Facilitated Diffusion
Channel protein let water molecules or a specific solute pass. A carrier protein alternates between two shapes, moving a solute across the membrane during the shape change. Passive (no energy); molecules move from high to low concentrations. Molecules are usually hydrophilic and/or large ex. ions, sugars, salts
CO2/O2: D, O, FD, and/or AT
D
Small hydrophobic: D, O, FD, and/or AT
D
Isotonic
Parts are in equilibrium
Phospholipid bilayer
Polar heads and non-polar tails. Diffusion of small atoms/molecules
Active Transport
Powered by ATP, takes energy. Moves solute from low to high concentration. Goes against concentration gradient. Requires transport protein. Ex. H+ ions, Na+/K+ pump, contransport of large hydrophillic molecules
Water potential equation
Pressure potential + Solute potential
Peripheral protein (outer surface)
Receptors, cell signaling, cell recognition, enzymes
Hypertonic solution effect on plant cell
Shrivels and membrane pulls away from cell wall
Diffusion
Small hydrophobic molecules move across the lipid bilayer from the high concentration area to the low concentration area. It doesn't need any extra energy- uses energy from environment.
Endocytosis
Takes in biological molecules by forming new vesicles from the plasma membrane. Cell membrane folds around particles that need to enter the cell, enclosing them in a vesicle
Integral protein
Transport large, hydrophillic molecules though lipid bilayer
osmosis
movement of water from areas of low solute concentration (and therefore high water) to high solute concentration (and therefore low water)
A red blood cell placed in a hypertonic medium will
shrink.
Hypertonic solution effect on animal cell
shriveled
Which of the following will pass through a cell membrane most easily?
small nonpolar molecules
The rate of diffusion is affected by which of the following?
temperature, size of molecules, and steepness of the concentration gradient
When sugar is mixed with water, equilibrium is reached when
the dissolved sugar molecules are evenly distributed throughout the solution.
Water potential is
the tendency of water to move from 1 area to another. Moves from high (less negative) water potential to a low (more negative) water potential
A 5% urea solution is hypotonic to a 10% urea solution.
true
Diffusion is one of the processes whereby materials are exchanged between a cell and its environment.
true
If a cell is placed in an isotonic medium, there will be no net movement of water.
true
Hypotonic solution effect on plant cell
very firm; normal
Osmosis is best defined as the movement of
water molecules across a membrane from an area of high water concentration to an area of lower concentration.
solution
whole mixture of solute and solvent
Isotonic solution effect on animal cell
Normal
From low to high solute concentration: D, O, FD, and/or AT
O, AT
Water: D, O, FD, and/or AT
O, FD
Large hydrophillic (ex. sugar): D, O, FD, and/or AT
O, FD, AT
Hypotonic solution effect on animal cell
burst
aquaporin
channel in phospholipid bilayer for water to travel though
solvent
does the dissolving
concentration
equals amount of solute
The molecules in a solid lump of sugar do not move.
false
Solute
gets dissolved
Gradient
gradual difference in concentration of solutes in a solution between two regions
Hypertonic
high solute, low free water; will cause the cell to lose water; is more concentrated than other parts
Active: D, O, FD, and/or AT
AT
Bulk flow: D, O, FD, and/or AT
AT
H+: D, O, FD, and/or AT
AT
Na+/K+ pump: D, O, FD, and/or AT
AT
Requires energy: D, O, FD, and/or AT
AT
From high to low solute concentration: D, O, FD, and/or AT
D, FD
Passive: D, O, FD, and/or AT
D, O, FD
Requires no energy: D, O, FD, and/or AT
D, O, FD
Bulk Transport kinds
Exocytosis, endocytosis
Glycoprotein
Involved in cell ID and cell to cell communication
Isotonic solution effect on plant cell
Limp
Peripheral protein (inner surface)
Maintain cell shape, enzymatic roles
Cytoskeleton
Maintain internal cellular shape
Cholesterol
Membrane stability
Exocytosis
Vesicles fuse with the plasma membrane and dumps out the contents of the vesicle
Hypotonic
low solute, high free water; will cause the cell to take up water; is less concentrated
Simple diffusion is defined as the movement of
molecules from areas of higher concentration to areas of lower concentration