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