*remember* - regulates what moves in and out of the cell cells transport various molecules ( water,...
TRANSCRIPT
Cellular Transport
Cell Membrane
*Remember* - regulates what moves in and out of the cell
Cells transport various molecules ( water, ions, salts, carbohydrates, lipids, proteins, etc) into and out of the cell
Diffusion Through the Membrane
All living cells exist in a liquid environment
Even in the desert, cells of cacti and scorpions are bathed in liquid
•Most important features of cell membrane is to regulate movement of molecules
Surface Area to Volume Ratio Homeostatsis must be achieved for cells to
survive
Raw materials must be taken in
Waste must be removed
Cells must be small to function correctly
The human body is composed of about 100 trillion cells
Cells range from 1 um – 100 um, with few exceptions
Small cells can exchange substances more rapidly than larger cells
Substances entering a small cell do not have to travel as far to get to the center
Materials travel the same speed, no matter the size of cell
Materials entering a larger cell take longer to reach the center
Cube Demonstration - Surface area Calculate the SA and V for the following cubes:
1 m x 1m x 1m 2m x 2m x
2m
3m x 3m x 3m
Cell membrane
In phospholipids bilayer – various proteins allow for materials to move in an out of cell
Different types of proteins play a vital role in life of cell
Cell Membrane
Marker proteins – attracted to a carbohydrate on cell surface
Helps other cells recognize their cell type – liver cell, heart cell, etc.
Cell Membrane
Receptor proteins – recognize and bind to specific substances ( ex: signal molecules outside of cell)
Cell Membrane
Transport proteins – aid in the movement of substances into and out of the cell
Complete Frayer model – 2 mins
Diffusion
Definition Characteristics
Examples Non-examples
Cell membrane surrounds the cell, and selectively allows center materials to leave or enter
Selective permeability – ability of the cell to determine what enters and leaves
Membrane is a highly fluid double layer called the phospholipid bilayer
Draw a phospholipid bilayer
Why does the cell membrane have to be selective?
-Needs to be able to regulatewhat goes in and out of cell- Maintain homeostasis!!!
Phospholipids
Head = hydrophilic = which means?
Tails = hydrophobic = which means?
Water-loving
Water-fearing
Proteins in the cell membrane
Marker proteins = identify cells
Transport proteins = transport large particles across membrane
Receptor proteins = capture signal molecules and cause a change in cell behavior
Cell Membrane Diagram
Simple Diffusion
Describe why an entire room can smell like a candle burning even the smell was all contained in a jar when purchased ?
Diffusion
In a solution, particles move constantly
Particles move from areas of high concentrations low concentrations = Diffusion
How does the model demonstrate one place where your body uses diffusion to its advantage?
Movement of materials across a membrane is called = transport
Passive transport – materials move down concentration gradient without the use of energy
2 Types:Unassisted: ( diffusion)Protein assisted: ( facilitated
diffusion)
Active Transport
occurs only when materials are transported across the membrane WITH energy
Describe the major difference between active and passive transport?
Active Transport
- Requires energy
- The energy is called ATP
- (adenine triphosphate )
Diffusion
Diffusion Video
Diffusion Simulation
Diffusion
In the space provided: create a higher concentration of circle in area 1 and a lower concentration in area 2. Draw an arrow indicating how the molecules.
Diffusion
Occurs until concentrations are equal on both sides
a.) State of equality is called equilibrium - That is what your cells want
Dynamic State of Equlibrium
when materials are passing in each direction, but not enough to upset the balance
Osmosis
diffusion of H2O molecules across the cell membrane
Osmosis - Aquaporins
Aquaporins – channels specific to water
Salt Water has a lower concentration of water than pure water
---that just means more SALT than WATER MOLECULES!
What do the prefixes shown below mean?
Hypo –
Hyper –
Iso -
Below
Above
Equal
Hypertonic
a solution with a higher concentration of dissolved particles than the inside of the cell
- AKA = LESS WATER in cell
HYPOTONIC
a solution with a lower concentration of dissolved particles than inside the cell – AKA more water!!
ISOTONIC
a solution with the same concentration of dissolved particles as the inside of the cell – AKA same concentration of water
Tonic – dissolved particles, not the water
Draw 3 containers with the 3 types of water concentration and identify solution types:
a.) Isotonic b.) Hypertonic c.) Hypotonic
Identify solution types
Type 1: Isotonic
-Cell remains normal size
- Equal amount of water inside and outside of cell
Type 2Hypertonic-Cell shrinks
- More water outside of cell than inside
Type 3: Hypotonic
-Cell Swells
- More water inside cell than in solution
Diffusion vs. Osmosis
Diffusion Osmosis
-Movement of materials(proteins, ATP, carbohydrates, etc)
-Two types:Unassisted and Assisted (Facilitated Diffusion)
-Movement of WATER
-Still considered a type of diffusion but just with WATER
