Copy into journal -Vocab Word list Diffusion Osmosis Selectively permeable Equilibrium Solution Facilitated Diffusion Hypertonic Hypotonic Isotonic Contractile Vacuole 11. Passive Transport 12. Active Transport 13. Endocytosis 14. Phagocytosis 15. Pinocytosis 16. Exocytosis 17. Protein Pump Know all of these words for the test

Transport Across the Cell Membrane Fluid Mosaic Model Video clip https://www.youtube.com/watch?v=Qqsf_UJcfBc Silent video- cell membrane and how it works https://www.youtube.com/watch?v=QQgXfuFyKM4

I. Structure of the Cell Membrane 2 layers (bilayer) of phospholipids with proteins imbedded known as the FLUID MOSAIC MODEL (molecules are in motion) Philic heads = water loving Phobic tails= water fearing This helps the cell interact in its aqueous environment.

II. The FUNCTIONS of the Cell Membrane Cell membranes help organisms maintain homeostasis by controlling what substances may enter or leave cells Boundary between the cell’s external and internal environment (like a Gatekeeper)

3. Selectively permeable – some molecules can cross it; others cannot – often based on size small molecules (H2O, CO2, O2) cross large molecules (starch, protein) cannot small molecule (water, carbon dioxide, oxygen) large molecule (starch, protein) cell membrane

To stay alive, a cell must exchange materials such as food, water, & wastes with its environment Molecules they want to let in: Molecules they want to let out: Molecules they DO NOT want to let in: Some substances can cross the cell membrane without any input of energy by the cell……often based on size The movement of such substances across the membrane is known as passive transport – without the use of energy sugar, oxygen, water carbon dioxide, waste viruses, bacteria

Receives, recognizes & responds to signals from other cells 4. Cell-to-cell communication Receives, recognizes & responds to signals from other cells The proteins attached to the surface of the cell membrane act as receptors for molecules like hormones or neurotransmitters (chemical produced by nerve cells). Cell Membrane Advanced video Click on image

Functions of the Cell Membrane The SHAPE of the cell receptor matches the SHAPE of the chemical signal, like a lock and key or puzzle pieces.

Example of a Cell Receptor: Hormone Signal (ex. hormone) Has receptors that match the hormone The binding of the hormone or neurotransmitter to the receptor results in a change in the cell’s metabolism.

Example of a Cell Receptor: neurotransmitter (signal)

Molecules that stop the signal from binding to the receptors prevent the cell from responding to the signal. These molecules are called inhibitors. (signal)

Specificity In biology, specificity refers to molecules that have a particular affinity for, or attachment to, each other In other words, they must fit together in order to function

YOUR TURN: Match the hormone to its target cell Cell A Cell B Cell C Hormone # 1 Hormone # 2 Hormone # 3 What is the target cell for hormone #1? What is the target cell for hormone #2? What is the target cell for hormone #3 Cell B Cell C Cell A

Question 1. Which statement regarding the functioning of the cell membrane of all organisms is not correct? The cell membrane forms a boundary that separates the cellular contents from the outside environment. The cell membrane forms a barrier that keeps all substances that might harm the cell from entering the cell. The cell membrane controls the movement of molecules into and out of the cell. The cell membrane is capable of receiving and recognizing chemical signals.

Question 2. In the given diagram of a single-celled organism, that arrows indicate various activities taking place. Which systems perform these same activities in humans? Respiratory, nervous and endocrine Excretory, respiratory, and reproductive Digestive, circulatory, and immune Respiratory, excretory, and digestive

Question 3. Cellular communication is illustrated in the diagram below Information can be sent from Cell A to Cell B because cell B is able to recognize signal 1 Cell B to Cell A because cell B is able to recognize signal 2 Cell B to Cell A because cell A is able to recognize signal 1 Cell A to Cell B because cell A is able to recognize signal 2

Question 4. Which substance are found on cell surfaces and respond to nerve and hormone signals? Vitamins and minerals Subunits of DNA Receptor molecules Starches and simple sugars

Question 5. Hormones and secretions of the nervous system are chemical messengers that Store genetic information Extract energy from nutrients Coordinate system interactions Carry out the circulation of materials

Question 6. In multi-celluar organisms, cells must be able to communicate with each other. Structures that enable most cells to communicate with each other are known as Chloroplasts Pathogenic agents Receptor molecules Antibiotics

TYPES OF TRANSPORT Across the Membrane Active & passive transport -http://www.youtube.com/watch?v=kfy92hdaAH0 No energy required Energy required

1. Passive Transport A. Diffusion Requires NO energy https://www.brainpop.com/science/cellularlifeandgenetics/passivetransport/ Requires NO energy A. Diffusion molecules move from an area of high concentration to an area of low concentration Molecules move down the concentration gradient - like going down a slide. Click on image to see How Diffusion works

Dynamic EquilibriuM when molecules “spread out” evenly throughout a space and stay in motion.

The rate of diffusion depends on temperature, size/surface area of the molecules, & type of molecules diffusing Substances that may diffuse: O2, CO2, glucose, amino acids, H2O

B. Osmosis Diffusion of water molecules. Watch How osmosis works: https://www.youtube.com/watch?v=w3_8FSrqc-I

Diffusion Demo – copy into Journal Indicator- substance that changes color in the presence of the substance it tests for Iodine (reddish -brown color) tests for starch. A positive test would change the color to a blue-black BEFORE AFTER Color of bag (cell): _______ Color of bag (cell): _______ Contents of bag: ________ Contents of bag: ________ Time lapse Semi- permeable membrane of cell starch iodine Cloudy white starch

Cells in different osmotic solutions (tonicity) Cells behave differently when placed in different solutions! This is due to OSMOSIS! Most cells are ~ 98% water! Three types of osmotic pressure: Isotonic Hypotonic Hypertonic Basic Rule for Determining types of Osmotic conditions…. Salt “SUCKS” – IT ACTUALLY ATTRACTS THE WATER If the area outside the cell has more salt – then water will be “pulled” out of the cell

Isotonic - "ISO" means the same 90% water 90% water

Let’s see….Isotonic Condition Cell is placed in 98% water Solution outside of cell has SAME water, same amount of other materials (i.e., salt) Therefore, solution is equal strength (iso) Water moves equally; Equilibrium exists 98% CELL STAYS THE SAME! 98%

Hypotonic (Hypo = less) Water moves in the cell Cell may burst, or organelles called “contractile vacuoles” remove excess water 90% water 80% water

Example of Osmosis Condition #1: More Water outside of cell Inside cell = 98% Water, 2% salt Outside cell = 100% Water, 0% salt 98% L Water moves into cell CELL SWELLS or BURSTS! 100% H CLICK HERE FOR DEMO!

HYPERTONIC – “Hyper = above” Water moves out of cell Cell will shrink (Plasmolysis) or die, plants wilt 80% water Why is it dangerous to drink sea water? Why does pouring salt on a slug kill it? 90% water

Example of Osmosis Condition #2: More water inside of cell Inside cell: 98% Water, 2% Salt Outside cell: 95% Water, 5% Salt 98% H Water moves out of cell 95% L CELL SHRIVELS!

Water relations and Cell shape in cells Animal cell: RBC Plant Cell HYPERTONIC HYPOTONIC HYPERTONIC HYPOTONIC

C. Facilitated Diffusion form of passive transport Facilitate- to guide or help. Protein channels help guide some molecules through the cell membrane.

Diffusion Demo – Journal entry Indicator- substance that changes color in the presence of the substance it tests for Iodine (reddish -brown color) tests for starch. A positive test would change the color to a blue-black BEFORE AFTER Color of bag (cell): _______ Color of bag (cell): _______ Contents of bag: ________ Contents of bag: ________ Time lapse Semi- permeable membrane of cell starch Starch & iodine iodine Blue-black cloudy white starch Starch & iodine

2. Active Transport Movement of molecules from areas of low concentration to areas of high concentration. Requires ATP (energy). The molecules move against/up the concentration gradient – like climbing a mountain. Teacher’s Pet video: https://www.youtube.com/watch?v=2-icEADP0J4

Comparing Types of Transport video: https://www.youtube.com/watch?v=2-icEADP0J4

Examples of Active Transport : Endocytosis- bring into the cell. Phagocytosis = Cytoplasm extends out and engulfs material to be brought into the cell. Ex. White blood cells and amoeba. 2. Exocytosis- move out of the cell. Watch phagocytosis animation: http://www2.sluh.org/bioweb/bi100/tutorials/thecell/phago_4.html

Endocytosis and Exocytosis

Watch Summary video http://www.youtube.com/watch?v=moPJkCbKjBs&feature=rel mfu Active & passive transport -http://www.youtube.com/watch?v=kfy92hdaAH0

“Everyday” Examples of Diffusion in the Human Body 1) absorption of nutrients What : nutrients (glucose, amino acids) From : small intestine To : blood Where : villi

What : oxygen carbon dioxide From : lungs blood To : blood lungs 2) gas exchange What : oxygen carbon dioxide From : lungs blood To : blood lungs Where : alveoli 3) in the placenta What : oxygen, carbon dioxide, nutrients wastes From : mom baby To : baby mom   Where : uterus