Transport of Cell Membrane

HIGH Concentration LOW Concentration

High Concentration LOW Concentration

HIGH Concentration LOW Concentration

Diffusion and osmosis

Types of Cellular Transport  Passive Transport cell does NOT USE ENERGY 1.Diffusion 2.Facilitated Diffusion 3.Osmosis  Active Transport cell USES ENERGY 1.Protein Pumps 2.Endocytosis 3.Exocytosis high low This is gonna be hard work!! high low Weeee!!! How “stuff” gets into and outside of the cell membrane

Bacon Frying… What do you smell? Why do you smell this?

Bacon Frying… Fat droplets are released into the air by the steam coming off of the bacon Causes the fat droplets (particles) to collide and disperse. In science terms… DIFFUSION IS OCCURING!

The bacon fat droplets (particles) diffuse from the area of high concentration (directly above the frying pan), to areas of low concentration (the room) Continues until equilibrium is reached  Particles equally distributed throughout the space (room) In the cell this is called HOMEOSTASIS!!

Diffusion Diffusion - Defined as the movement of particles from areas of high concentration to areas of low concentration (down the concentration gradient) – Particles spread out – Ex: Solute = perfume Solvent = the air Low Solute Concentration High Solute Concentration

Diffusion

What Can go through? Oxygen Carbon dioxide

What 3 things effect the rate of diffusion? (how fast diffusion occurs)

Diffusion rate (how fast it occurs) depends on: 1. Size- smaller molecules move more easily 2. Concentration- high concentration = faster spread Ex: The more bacon you have (=more fat droplets released), the faster the smell will spread throughout the room 3. Temperature- high temps speed up the process Which will cause the smell to disperse faster? Cold bacon in a frying pan and the stove is OFF OR Bacon in a frying pan and the stove in ON

What is a semi-permeable membrane? A membrane that allows certain molecules to pass through it by diffusion or osmosis Think about a Ping-Pong net.. Which would pass through?

Cell membranes are semi-permeable Water and some gases move through the membrane easily, while larger molecules like proteins and sugars do not. Cells must regulate- molecules move from internal environment to external environment (and vice versa) so that both environments have equal concentrations. – Animation: How Osmosis Works Animation: How Osmosis Works

Osmosis water Diffusion that involves water. Movement of water across a semi-permeable membrane  WATER moves across the cell membrane Water moves across the cell membrane from areas of low solute concentration to high solute concentration

Osmosis water Diffusion that involves water. Movement of water across a semi-permeable membrane Water moves from areas of low solute concentration to areas of high solute concentration Why do your fingers “shrivel–up” when you are in the water?

Effects of Osmosis on Life Osmosis- diffusion of water through a selectively permeable membrane. There are 3 types of solutions (=Tonicity) 1.) Isotonic 2.) Hypertonic 3.) Hypotonic

Solution Cell Solution Cell

Isotonic Solution Solutions that contain the same concentration of solutes as the cytoplasm are called isotonic (or normal saline) solutions. There is no net movement of water either into or out of the cell. Cells maintain their normal shape.

Isotonic Solution Isotonic Isotonic  The concentration of solutes in the external solution is equal to the concentration of solutes inside the cell. Result  Water moves equally in both directions and the cell remains same size! (Dynamic Equilibrium)

Hypertonic Solution A hypertonic solution is a solution that contains more solutes than the cytoplasm of the cell. (hyper) Has less water than the cell and water moves out of the cell. The cells shrink.

Hypertonic Solution Hypertonic: The solution has a higher concentration of solutes and a lower concentration of water than inside the cell. (High solute; Low water) Result: Water moves from inside the cell into the solution: Cell shrinks (Plasmolysis/crenation)! shrinks

Hypotonic Solution A hypotonic solution contains less solute (thus, more water) than the cytoplasm of the cells. The water will move into the cells resulting in the swelling and lysis of the cells.

Hypotonic Solution Hypotonic: The solution has a lower concentration of solutes and a higher concentration of water than inside the cell. (Low solute; High water) Result: Water moves from the solution to inside the cell): Cell Swells and bursts open (cytolysis)!

Let’s take a closer look! Z8MtF3C6M

What type of solution are these cells in ? A C B

A CB Hypertonic Isotonic Hypotonic

Tonicity  Used to compare different solutions  Hypertonic- higher solute concentration relative to another *think hyperactive  Hypotonic- lower solute concentration relative to another *think hypothermia  Isotonic- equal solute concentrations between two solutions

39 CELL 10% NaCL 90% H 2 O 10% NaCL 90% H 2 O What is the direction of water movement? The cell is at _______________. ENVIRONMENT

40 Cell in Isotonic Solution CELL 10% NaCL 90% H 2 O 10% NaCL 90% H 2 O What is the direction of water movement? The cell is at _______________. equilibrium ENVIRONMENT NO NET MOVEMENT

41 CELL 10% NaCL 90% H 2 O 20% NaCL 80% H 2 O What is the direction of water movement??

42 Cell in Hypotonic Solution CELL 10% NaCL 90% H 2 O 20% NaCL 80% H 2 O The cell is HYPERTONIC and the solution is HYPOTONIC

43 CELL 15% NaCL 85% H 2 O 5% NaCL 95% H 2 O What is the direction of water movement? ENVIRONMENT

44 Cell in Hypertonic Solution CELL 15% NaCL 85% H 2 O 5% NaCL 95% H 2 O The cell is HYPOTONIC and the solution is HYPERTONIC ENVIRONMENT

45 Cells in Solutions

46 Isotonic Solution NO NET MOVEMENT OF H 2 O (equal amounts entering & leaving) Hypotonic Solution CYTOLYSIS Hypertonic Solution PLASMOLYSIS

47 Cytolysis & Plasmolysis Cytolysis Plasmolysis

48 Osmosis in Red Blood Cells Isotonic Hypotonic Hypertonic

What Happens to Blood Cells? 49