AS Biology, Cell membranes and Transport 1 My Future Plan 1. Write 3 things that motivate you to be successful in what you are doing 2. What do you want to do when you grow up? (in 10 years time) 3. What do you need to get there? 4. Draw a flow chart of how you intend to achieve your future goal (use different colors to represent each stage) 5. What do you wish I know about you?

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3 RootwordsQuiz

4 1. prokaryote pro / karyo 1. / 2. eukaryote eu / karyo 2./ 3. symbiosis sym / bio / osis 3.together / / 4. endoplasm endo / plasm 4. / 5. cytoplasm cyto / plasm 5. / Rootwords Quiz

AS Biology, Cell membranes and Transport5 Bell warm up Draw and color a picture that demonstrates Diffusion  Fill up your agenda for the week Mon:Cell Transport Tue: Osmosis Wed/Thurs: Lab Fri: Review Cell Tranport Rootwords quiz Rootwords quiz Mon (9 th ): TEST (Cell Transport)

AS Biology, Cell membranes and Transport 6 Cell Boundaries and Transport through cell membranes

AS Biology, Cell membranes and Transport7 Cell membranes Cell membranes Function  Encloses the cell  Provides protection and support  Regulates what goes in and out of the cell

AS Biology, Cell membranes and Transport8 Structure: 1. Phospholipid bilayer 2. Proteins embedded in it: many form channels and pumps that move molecules across the membrane. 3. Cholesterol – adds stability 4. SELECTIVELY PERMEABLE 4. SELECTIVELY PERMEABLE

AS Biology, Cell membranes and Transport 9 Lipid bilayer Cell membrane is composed of : a phospholipid bilayer (2 layers of lipid) a phospholipid bilayer (2 layers of lipid) proteins and carbohydrates proteins and carbohydrates Also called the fluid mosaic Also called the fluid mosaic Selectively permeableSelectively permeable

AS Biology, Cell membranes and Transport10 Types of Transport Passive Transport  No energy required  Flows from high concentration to low 1. DIFFUSION 2. OSMOSIS 3. FACILITATED DIFFUSION Active Transport  Requires energy  Flows from low concentration to high 1. MOLECULAR TRANSPORT 2. ENDOCYTOSIS 3. EXOCYTOSIS page (Biology book) page (Biology book)

AS Biology, Cell membranes and Transport11 Diffusion Diffusion Movement of molecules from a region of high concentration to a region of low concentration. The molecules are usually small Examples: Oxygen(O 2 ), Carbon dioxide (CO 2 ) Alcohol

AS Biology, Cell membranes and Transport12  Diffusion Diffusion

AS Biology, Cell membranes and Transport13 Diffusion of liquids

AS Biology, Cell membranes and Transport 14 Diffusion is the net movement of molecules (or ions) from a region of their high concentration to a region of their lower concentration. The molecules move down a concentration gradient. Molecules have kinetic energy, which makes them move about randomly. As a result of diffusion molecules reach an equilibrium where they are evenly spread out. This is when there is no net movement of molecules from either side.Diffusion is the net movement of molecules (or ions) from a region of their high concentration to a region of their lower concentration. The molecules move down a concentration gradient. Molecules have kinetic energy, which makes them move about randomly. As a result of diffusion molecules reach an equilibrium where they are evenly spread out. This is when there is no net movement of molecules from either side.

AS Biology, Cell membranes and Transport15 DIFFUSION Diffusion is a PASSIVE process which means no energy is used to make the molecules move, they have a natural kinetic energy.

AS Biology, Cell membranes and Transport16 Diffusion of Bromine

AS Biology, Cell membranes and Transport17 Diffusion of Bromine

AS Biology, Cell membranes and Transport18 Diffusion through a membrane Cell membrane Inside cell Outside cell

AS Biology, Cell membranes and Transport19 Diffusion through a membrane Cell membrane Inside cell Outside cell diffusion

AS Biology, Cell membranes and Transport20 Diffusion through a membrane Cell membrane Inside cell Outside cell EQUILIBRIUM

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AS Biology, Cell membranes and Transport23 What determines the rate of diffusion? There 4 factors: 1.. The bigger the difference between the two sides of the membrane the quicker the rate of diffusion. 1. The steepness of the concentration gradient. The bigger the difference between the two sides of the membrane the quicker the rate of diffusion. 2.. Higher temperatures give molecules or ions more kinetic energy. Molecules move around faster, so diffusion is faster. 2. Temperature. Higher temperatures give molecules or ions more kinetic energy. Molecules move around faster, so diffusion is faster. 3. The greater the surface area the faster the diffusion can take place. This is because the more molecules or ions can cross the membrane at any one moment. 3. The surface area. The greater the surface area the faster the diffusion can take place. This is because the more molecules or ions can cross the membrane at any one moment. 4.. Large molecules need more energy to get them to move so they tend to diffuse more slowly. Non-polar molecules diffuse more easily than polar molecules because they are soluble in the non polar phospholipid tails. 4. The type of molecule or ion diffusing. Large molecules need more energy to get them to move so they tend to diffuse more slowly. Non-polar molecules diffuse more easily than polar molecules because they are soluble in the non polar phospholipid tails.

AS Biology, Cell membranes and Transport24 Molecules that diffuse through cell membranes 1. Oxygen – Non-polar so diffuses very quickly. 1. Carbon dioxide – Polar but very small so diffuses quickly. 2. Water – Polar but also very small so diffuses quickly.

AS Biology, Cell membranes and Transport25 Bell warm up 11/11/08 1. Define diffusion 2. Draw a diagram to illustrate (show) diffusion

AS Biology, Cell membranes and Transport26 Facilitated diffusion Facilitated diffusion  Movement of molecules from high concentration to low concentration with the help of membrane proteins.  Do NOT require energy!!!!!  The proteins serve as carriers.  Ex: Glucose moves by this method

AS Biology, Cell membranes and Transport27 Facilitated Diffusion through a membrane Cell membrane Inside cell Outside cell Protein channel diffusion

AS Biology, Cell membranes and Transport28 Facilitated diffusion  Large polar molecules such as glucose and amino acids, cannot diffuse across the phospholipid bilayer. Also ions such as Na + or Cl - cannot pass.  These molecules pass through protein channels instead. Diffusion through these channels is called FACILITATED DIFFUSION.  Movement of molecules is still PASSIVE just like ordinary diffusion, the only difference is, the molecules go through a protein channel instead of passing between the phospholipids.

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AS Biology, Cell membranes and Transport30 Facilitated Diffusion through a membrane Cell membrane Inside cell Outside cell Protein channel

AS Biology, Cell membranes and Transport31 Facilitated Diffusion through a membrane Cell membrane Inside cell Outside cell Protein channel diffusion

AS Biology, Cell membranes and Transport32 Facilitated Diffusion through a membrane Cell membrane Inside cell Outside cell Protein channel diffusion EQUILIBRIUM

AS Biology, Cell membranes and Transport33 Facilitated Diffusion: Molecules will randomly move through the opening like pore, by diffusion. This requires no energy, it is a PASSIVE process. Molecules move from an area of high concentration to an area of low conc. Facilitated Diffusion: Molecules will randomly move through the opening like pore, by diffusion. This requires no energy, it is a PASSIVE process. Molecules move from an area of high concentration to an area of low conc.

AS Biology, Cell membranes and Transport34 Facilitated diffusion

AS Biology, Cell membranes and Transport35 Osmosis ‘The diffusion of water from an area of high concentration of water molecules (high water potential) to an area of low concentration of water (low water potential) across a SELECTIVELY permeable membrane.’ ‘The diffusion of water from an area of high concentration of water molecules (high water potential) to an area of low concentration of water (low water potential) across a SELECTIVELY permeable membrane.’

AS Biology, Cell membranes and Transport36 Osmosis Cell membrane partially permeable. Inside cell Outside cell VERY High conc. of water molecules. High water potential. VERY Low conc. of water molecules. High water potential. Sugar molecule DILUTE SOLUTION CONCENTRATED SOLUTION

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AS Biology, Cell membranes and Transport38 Osmosis Cell membrane partially permeable. Inside cell Outside cell High conc. of water molecules. High water potential. Low conc. of water molecules. High water potential. OSMOSIS

AS Biology, Cell membranes and Transport39 Osmosis Cell membrane partially permeable. Inside cell Outside cell OSMOSIS EQUILIBRIUM. Equal water concentration on each side. Equal water potential has been reached. There is no net movement of water

AS Biology, Cell membranes and Transport40 Osmosis Solution is made up of : Solute (solid)+ Solvent (liquid) Solution can be Isotonic, Hypotonic or Hypertonic  Iso means EQUAL (the same)  Hypo means LESS (less solute  more water)  Hyper means MORE (more solute)

AS Biology, Cell membranes and Transport41 Isotonic Solution  The solute concentration outside the cell is EQUAL to the solute concentration inside the cell.  Water will move back and forth EQUALLY but have no affect on the overall amount of water on either side.  No change in turgor pressure.

AS Biology, Cell membranes and Transport42 Isotonic Solution  Effect on Animal Cell: No overall effect. The cell is healthy.

AS Biology, Cell membranes and Transport43 Isotonic Solution  Effect on Plant Cells No overall effect.

AS Biology, Cell membranes and Transport44 Hypotonic Solution  The solute concentration outside the cell is LESS than the solute concentration inside the cell.  Water will move INTO the cell.  Causes increase in turgor pressure

AS Biology, Cell membranes and Transport45 Hypotonic Solution  Effects on Animal Cell: Cells can LYSIS from increased water pressure. Some cells have contractile vacuoles to pump out excess water.

AS Biology, Cell membranes and Transport46 Hypotonic Solution  Effect on Plant Cells: The central vacuole will fill with WATER and the cells will become stiff and rigid or TURGID. Cell walls keep the plant cells from bursting.

AS Biology, Cell membranes and Transport47 Hypertonic Solution  The solute concentration outside the cell is MORE than the solute concentration inside the cell.  Water will move OUT OF the cell  Decrease in turgor pressure.

AS Biology, Cell membranes and Transport48 Hyptertonic Solution  Effect on Animal Cells: Cells will SHRIVEL and become DEHYDRATED. Cells may die.

AS Biology, Cell membranes and Transport49 Hypertonic Solution  Effect on Plant Cells: The central vacuole loses WATER and the cell shrinks, causing wilting. This is called PLASMOLYSIS. Cells may die.

AS Biology, Cell membranes and Transport50 Animal Cells

AS Biology, Cell membranes and Transport51 Active Transport Active Transport  Requires energy  Moves from low concentration to high concentration  Will not reach dynamic equilibrium Types 1. MOLECULAR TRANSPORT 2. ENDOCYTOSIS 3. EXOCYTOSIS

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AS Biology, Cell membranes and Transport56 Molecular Transport Molecular Transport  Movement of small molecules and ions across a membrane against concentration gradient with help of energy requiring protein pumps.  Ca, K and Na ions are carried this way.  A lot of energy is required!!!!!!

AS Biology, Cell membranes and Transport57 These are carrier proteins. They do not extend through the membrane. They bond and drag molecules through the bilipid layer and release them on the opposite side.

AS Biology, Cell membranes and Transport58 Endocytosis is the case when a molecule causes the cell membrane to bulge inward, forming a vesicle. Phagocytosis is the type of endocytosis where an entire cell is engulfed. Pinocytosis is when the external fluid is engulfed.Endocytosis is the case when a molecule causes the cell membrane to bulge inward, forming a vesicle. Phagocytosis is the type of endocytosis where an entire cell is engulfed. Pinocytosis is when the external fluid is engulfed.EndocytosisPhagocytosisEndocytosisPhagocytosis Remember: Endo  within/inside Phago  eat up Pino  drink up

AS Biology, Cell membranes and Transport59 Cell Membrane - Function - Endocytosis The cell membrane can also engulf structures that are much too large to fit through the pores in the membrane proteins this process is known as endocytosis. In this process the membrane itself wraps around the particle and pinches off a vesicle inside the cell. In this animation an ameba engulfs a food particle.

AS Biology, Cell membranes and Transport60 Exocytosis The opposite of endocytosis is exocytosis. Exocytosis is the term applied when transport is out of the cell. Large molecules that are manufactured in the cell are released through the cell membrane. Exocytosis Exo  outside

AS Biology, Cell membranes and Transport61 Draw a flow chart of cellular transport

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AS Biology, Cell membranes and Transport65 Cellular Transport flow chart

AS Biology, Cell membranes and Transport66 Osmosis Lab Osmosis is the movement of water from a region of high concentration to a region of low concentration through a selectively permeable membrane Cucumber Triple beam balance Salt water Distilled water

AS Biology, Cell membranes and Transport67 Plasmolysis Lab Plasmolysis: Shrinkage or contraction of the cell content from the cell wall caused by loss of water through osmosis Elodea in distilled water Elodea in salt water

AS Biology, Cell membranes and Transport68 Elodea in distilled water Elodea in salt water