BELL RINGER What part of the cell controls the materials that enter and exit the cell? What type of biomolecule is this structure made out of?

Movement Through a Membrane Video http://people.eku.edu/ritchisong/301notes1.htm

HOMEOSTASIS REACP VIDEO (3) Answer the first 4 questions on your unit 6 notes while watching the short 3 min recap/review/intro video.

Cell Membrane Function: Regulates what enters and leaves the cell and provides support. Made of: phospholipid: Support/Structure Proteins: Act as channels and pumps Carbohydrates: Act like ID cards. Selectively Permeable: some substances can pass across and others cannot.

Phospholipid Bilayer Outside of cell Water Inside of cell Water membrane Proteins Protein channel Lipid bilayer Carbohydrate chains Inside of cell Water

Phospholipid Polar Head Hydrophilic Non polar Tail Hydrophobic

Diffusion Diffusion: movement of molecules from high to low concentration directly across the membrane Simple Diffusion Passive Transport: Does not require energy Molecules move with the concentration gradient Molecules continue until they reach equilibrium (equal concentrations on both sides of the membrane).

Concentration Gradient Movement from high concentration to low concentration

Facilitated Diffusion Facilitated Diffusion: protein channels help some LARGE molecules diffuse across the membrane. Large molecules are unable to cross the cell membrane. Protein channels are specific for large molecules. Only occurs if there is a concentration gradient. Does not require energy.

Facilitated Diffusion Glucose molecules High Concentration Cell Membrane Protein channel Low Concentration

Video Recap

HIGH LOW

Concentration Gradient High Concentration Molecules moving from high concentrations to low Low Concentration

Bell Ringer What is diffusion? Diffusion is movement of molecules across a membrane. What is a concentration gradient? Concentration gradient is movement of molecules from high concentration to low concentration. What are two ways that molecules can get into a cell? Two ways that molecules can get into a cell are diffusion and facilitated transport.

POTATO LAB!! What will keep potatoes fresh and why? Understand how cells maintain homeostasis through cell transport.

Bell Ringer How do small molecules move across the membrane? In your potato lab what was causing the potatoes to lose “freshness”. How are potato cells similar to human cells?

Osmosis VIDEO (10) Osmosis: diffusion of water through a selectively permeable membrane from high to low concentration. Isotonic: same amount of water and solute on both sides Hypotonic: less solute side Hypertonic: more solute side Example of a solute in a solution would be SALT in saltwater. Salt is a SOLUTE remember solutes SUCK!

Osmosis Cell membrane Water molecules Higher Concentration of Water Lower Concentration of Water Sugar molecules

SAME SAME Swell Swell Shrink Shrink

Question: What kind of solution is salt water compared to a cell? Hypertonic because it has a higher salt concentration compared to a cell. Question: What happens to a cell if we put it in salt water? Water will leave the cell by osmosis causing the cell to shrink. Hypotonic Hypertonic Isotonic

Osmosis The video clip explains you can also think of water as moving to a _______ concentration of solute molecules Why can it also be viewed this way? Solutes suck water towards them Higher

Fish Hypertonic- Water moves out of the fish and fish shrinks SAVE ME! Hypo

Brain swelling treatment- adding a hypertonic saline Explain ….

Active Transport LOW TO HIGH Active Transport: the movement of molecules against the concentration gradient (uphill). Requires energy (ATP) Often compared to a pump Example: The Sodium (Na+) Potassium (K+) Pump in the cell membrane pumps sodium out of the cell and potassium into the cell. AGAINST

Concentration Gradient High Concentration Molecules moving from low concentrations to high Energy Low Concentration

Active Transport http://www.youtube.com/watch?v=STzOiRqzzL4&feature=player_detailpage Molecule to be carried Low Concentration Cell Membrane High Concentration Molecule being carried Low Concentration Cell Membrane High Concentration ATP Energy

Movement Direction: Endocytosis: (enter) particles are taken into the cell Exocytosis: (exit) particles are removed from the cell

Bell ringer How does water move across the membrane? What is an isotonic solution? What is a hypotonic solution? What will happen if a blood cell is placed into a hypertonic solution? Amoeba sisters video review

Bell Ringer Define Osmosis: Diffusion: Active transport: Passive transport: Semipermeable: movement of water across a membrane towards the area of higher solute concentration. Movement of molecules from high to low concentration Movement of molecule from low to high concentration using energy Movement of molecule from high to low concentration without using energy Some molecules can pass through while others cannot

Bell Ringer Hydrophilic: Hydrophobic: Solute: Isotonic: Hypertonic: Hypotonic: Equilibrium: Water loving, polar head of phospholipid Water hating, non-polar tail of phospholipid Substance that sucks water towards it in solution, Sugar or salt Equal amount of solute and water Side with more solute Side with less solute Amount of all molecules on both sides of membrane are equal

Bell Ringer: What are cell membranes made of? What happens to a cell if it is placed in salt water? What is the function of the ribosome? Where does aerobic respiration take place in plant and animal cells? Which organelle controls the cell? What is the term for water moving through a membrane? How does oxygen pass into or out of a cell?

Bell Ringer: If a molecule is moving down the concentration gradient, is it going from high concentration to low concentration or low to high concentration? Does diffusion require energy? What will happen to a cell if you put it in a hypertonic solution? Molecules continue to move down the gradient until they reach what? Draw and label a cell membrane.

Bell Ringer: What are the 3 parts of Cell Theory? Which organelle is the Control Center of the cell? Which organelle controls the passage of materials in and out of the cell? Which organelle is where proteins are made? What are 2 organelles that are in plant cells and not animal cells? What is the main difference between a prokaryotic and a eukaryotic cell?

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