Structure of the Cell or Plasma Membrane The cell membrane is like a mosaic of many parts

Structure of the Cell or Plasma Membrane


The cell membrane is like a mosaic of many parts



It is made of a layer of

studded with .



It is made of a double (bi-) layer of

studded with .



It is made of a double (bi-) layer of phospholipids studded with

.




proteins .




proteins .Why are membranes made of two layers of phospholipids?



It is made of a double (bi-) layer of phospholipids studded with proteins .

Why are membranes made of two layers of phospholipids?The two layers create a strong but flexible layer protecting the cell. The fatty inside of the membrane prevents many substances from entering or leaving the cell uncontrollably.

Selectively Permeable Cell MembraneThe plasma membrane is selectively permeable meaning that

Selectively Permeable Cell MembraneThe plasma membrane is selectively permeable meaning that only some things can go through .


Called a fluid mosaic model because it has many different parts to allow molecules through



A substance’s ability to pass through the membrane depends on its and .



A substance’s ability to pass through the membrane depends on its size and

.



A substance’s ability to pass through the membrane depends on its size and charge .

Nonpolar molecules

Small polar molecules

Large polar molecules

Ions

O2

H20

C6H12O6

H+, Na+, Cl-

Movement of MoleculesConcentration:

Movement of MoleculesConcentration: The mass of a solute in a given volume of solutions (mass/volume)

Movement of MoleculesConcentration: The mass of a solute in a given volume of solutions (mass/volume)Substances moves so that

can be reached or when the concentration is the same across a space.

Movement of MoleculesConcentration: The mass of a solute in a given volume of solutions (mass/volume)Substances moves so that equilibrium can be reached or when the concentration is the same across a space.


Concentration gradient:


Concentration gradient: the difference in concentration on one side of a barrier and another

Movement of MoleculesA substance tends to move WITH or DOWN its concentration gradient, meaning it moves from an area where its concentration is

to an area where its concentration is , until equilibrium is achieved.

Movement of MoleculesA substance tends to move WITH or DOWN its concentration gradient, meaning it moves from an area where its concentration is high to an area where its concentration is , until equilibrium is achieved.

Movement of MoleculesA substance tends to move WITH or DOWN its concentration gradient, meaning it moves from an area where its concentration is high to an area where its concentration is low , until equilibrium is achieved.



Movement of MoleculesA substance reluctantly moves AGAINST its concentration gradient, meaning it moves from an area where its concentration is ___ to an area where its concentration is .

Movement of MoleculesA substance reluctantly moves AGAINST its concentration gradient, meaning it moves from an area where its concentration is high to an area where its concentration is .

Movement of MoleculesA substance reluctantly moves AGAINST its concentration gradient, meaning it moves from an area where its concentration is low to an area where its concentration is high.

Movement of MoleculesWhen substances move against their concentration gradients, equilibrium will NOT be reached. Substances don’t like moving that way. To coax them into moving, energy has to be used.

Review some terms:Solute:

Review some terms:Solute: a substance that is dissolved in a solvent to make a solution


Solvent:


Solvent: substance in which a solute is dissolved to form a solution

Words to compare the concentrations of SOLUTES in two areas:Hypertonic:

Words to compare the concentrations of SOLUTES in two areas:Hypertonic: when comparing two solutions, the solution with the greater concentration of solutes


Hypotonic:


Hypotonic: when comparing two solutions, the solution with the lesser concentration of solutes



Isotonic:



Isotonic: when the concentration of two solutions is the same

Does not require energy

Diffusion or Passive TransportMovement of materials from high concentrations ( solutions) to low concentrations ( solutions)

Diffusion or Passive TransportMovement of materials from high concentrations (hypertonic solutions) to low concentrations (

solutions)

Diffusion or Passive TransportMovement of materials from high concentrations (hypertonic solutions) to low concentrations (hypotonic solutions)

Diffusion or Passive TransportWhat types of molecules can passively diffuse through the membrane and why?

Diffusion or Passive TransportWhat types of molecules can passively diffuse through the membrane and why?Nonpolar molecules and small polar molecules; small molecules can pass through small spaces; nonpolar molecules are not repelled and so can easily pass through.

Facilitated DiffusionDiffusion of substances across a membrane through

.

Facilitated DiffusionDiffusion of substances across a membrane through protein channels .


To facilitate means to so these molecules get help crossing the membrane through proteins.


To facilitate means to help so these molecules get help crossing the membrane through proteins.

Facilitated DiffusionDiffusion of substances across a membrane through protein channels.

To facilitate means to help so these molecules get help crossing the membrane through proteins.

Protein channels can be open all of the time or gated, meaning some sort of stimulus is need to open the channel in the protein.

Facilitated DiffusionWhat types of molecules diffuse through protein channels and why?

Facilitated DiffusionWhat types of molecules diffuse through protein channels and why?Specific substances that fit the specific shape of a protein (like glucose). They need help because they are too big to pass through the membrane otherwise.

OsmosisDiffusion of water through a membrane


Water moves from an area of water concentrations to water concentrations


Water moves from an area of high water concentrations to low water concentrations



Hypertonic solutions (high solute concentration) have concentrations of water.



Hypertonic solutions (high solute concentration) have low concentrations of water.

OsmosisDiffusion of water through a membraneWater moves from an area of high water concentrations to low water concentrations


Hypotonic solutions (low solute concentrations) have concentrations of water.



Hypotonic solutions (low solute concentrations) have high concentrations of water.




So water moves from solutions to solutions




So water moves from hypotonic solutions to solutions




So water moves from hypotonic solutions to hypertonic solutions

= solute molecule

= water molecule

Requires energy

Active TransportMovement of materials from low concentrations (

solutions) to high concentrations ( solutions).

Active TransportMovement of materials from low concentrations (hypotonic solutions) to high concentrations (

solutions).

Active TransportMovement of materials from low concentrations (hypotonic solutions) to high concentrations (hypertonic solutions).

Active TransportMovement of materials from low concentrations (hypotonic

solutions) to high concentrations (hypertonic solutions).

Small molecules must pass through a protein pump to enter the cell.



This process requires energy, often in the form of



This process requires energy, often in the form of ATP

Bulk TransportMovement of large molecules or large groups of molecules into or out of cells through vesicles.

Moves molecules from low concentrations to high concentrations

Bulk TransportEndocytosis:

Bulk TransportEndocytosis: the process of taking material into the cell by means of infoldings, or pockets of the cell membrane


Phagocytosis:


Phagocytosis: “cell eating;” when the cell takes in solids



Pinocytosis:



Pinocytosis: “cell drinking;” when the cell takes in liquids

Bulk TransportExocytosis:

Bulk TransportExocytosis: the process of releasing material from the cell; membrane vesicle fuses with the cell membrane, forcing the contents out of the cell

Bulk TransportExocytosis: the process of releasing material from the cell; membrane vesicle fuses with the cell membrane, forcing the contents out of the cell

Documents

Structure of the Cell or Plasma Membrane The cell membrane is like a mosaic of many parts