MEMBRANE GET OUT YOUR LAB s GET OUT

MEMBRANE - GET OUT YOUR LAB ? s

GET OUT YOUR VOCABULARY NOTES!

PHOTOGRAPH OF A CELL MEMBRANE

HOMEOSTASIS • BALANCED INTERNAL CONDITION OF CELLS • MAINTAINED BY CELL MEMBRANE

SELECTIVELY PERMEABLE • ONLY CERTAIN MATERIALS ALLOWED TO CROSS THE CELL MEMBRANE • “BOUNCER”

STRUCTURE OF THE CELL MEMBRANE

Membrane Components 1. Phospholipids 3. Proteins (peripheral and integral) 2. Cholesterol 7 4. Carbohydrates (glucose)

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PHOSPHOLIPIDS -MAKE UP THE MAJORITY OF CELL MEMBRANE -Each contains 2 fatty acid tails & polar head 9

PHOSPHOLIPIDS CONTINUED heads are hydrophilic “water loving” tails are hydrophobic “water fearing”

LIPID BILAYER • 2 LAYERS OF PHOSPHOLIPID THAT MAKE UP CELL MEMBRANE

FLUID MOSAIC MODEL -NAME OF CELL MEMBRANE MODEL FLUID- B/C INDIVIDUAL PHOSPHOLIPIDS & PROTEINS MOVE LIKE IN A LIQUID MOSAIC- B/C OF THE PATTERN PRODUCED BY THE SCATTERED PROTEIN

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SOLUTION • 2 OR MORE SUBSTANCES MIXED EVENLY TOGETHER • EX) CYTOPLASM

2 PARTS TO A SOLUTION • 1) SOLVENT • 2) SOLUTE

SOLVENT • SUBSTANCE IN SOLUTION THAT THERE IS MORE OF • EX) IN CYTOPLASM SOLVENT IS WATER

SOLUTE SUBSTANCE(S) IN SOLUTION THAT THERE IS LESS OF EX) IN CYTOPLASM SOLUTE INCLUDES: SALT, K+, GLUCOSE

SOLUTION PROBLEM • A SOLUTION IS 75% WATER, 10% SALT, AND 15 % SUGAR. • SOLVENT? • SOLUTE?

CONCENTRATION • RATIO OF SOLUTE MOLECULES TO SOLVENT MOLECULES IN A SOLUTION • SOLUTE &/OR SOLVENT = CONC • SOLUTE &/OR SOLVENT = CONC

COMPARING CONCENTRATION OF 2 SOLUTIONS 1)BOTH ISOTONIC 2) 1 IS HYPERTONIC & 1 IS HYPOTONIC

ISOTONIC • 2 SOLUTIONS HAVE EQUAL CONCENTRATION

HYPERTONIC • SOLUTION W/ HIGHER CONCENTRATION (MORE SOLUTE)

HYPOTONIC • SOLUTION W/ LOWER CONCENTRATION (LESS SOLUTE)

TYPES OF TRANSPORT ACROSS CELL MEMBRANES 1. 2. 3. 4. 5. SIMPLE DIFFUSION OSMOSIS FACILITATED DIFFUSION ACTIVE TRANSPORT ENDOCYTOSIS 1. 2. PINOCYTOSIS PHAGOCYTOSIS 6. EXOCYTOSIS

DIFFUSION • SMALL SOLUTE MOLECULES MOVE FROM SOLUTION W/ HIGH CONCENTRATION (HYPERTONIC) TO SOLUTION W/ LOW CONCENTRATION (HYPOTONIC) • NO ENERGY (PASSIVE) • PASS THROUGH LIPID BILAYER

DIFFUSION

DIFFUSION OF LIQUIDS 27

DIFFUSION THROUGH A MEMBRANE Cell membrane Solute moves DOWN concentration gradient (HIGH to LOW)

OSMOSIS • DIFFUSION OF WATER ACROSS A MEMBRANE • SOLVENT MOVES FROM HYPOTONIC TO HYPERTONIC SOLUTION • NO ENERGY • PASSAGE THROUGH Diffusion across a membrane Semipermeable membrane 29

DIFFUSION OF H 2 O ACROSS A MEMBRANE High H 2 O potential Low solute concentration High solute concentration 30

AQUAPORINS • WATER CHANNELS • PROTEIN PORES USED DURING OSMOSIS WATER MOLECULES

OSMOTIC PRESSURE • THE AMOUNT OF PRESSURE THAT IS PLACED ON A SOLUTION TO KEEP IT FROM PASSING THROUGH THE MEMBRANE.

OSMOTIC PRESSURE 33

CELL IN ISOTONIC SOLUTION 10% Na. CL 90% H 2 O Extra Cellular Fluid CELL(Cytoplasm) 10% Na. CL 90% H 2 O NO NET MOVEMENT What is the direction of water movement? The cell is at equilibrium.

What is the direction of water movement? 10% Na. CL 90% H 2 O CELL 20% Na. CL 80% H 2 O

What is the direction of water movement? 15% Na. CL 85% H 2 O Extra. Cellular Fluid CELL 5% Na. CL 95% H 2 O

CELLS IN SOLUTIONS

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

CYTOLYSIS & PLASMOLYSIS Cytolysis Plasmolysi s

OSMOSIS IN RED BLOOD CELLS Isotonic Hypertonic

WHAT HAPPENS TO BLOOD CELLS?

hypotonic hypertonic isotonic hypotonic 42

Three Forms of Transport Across the Membrane 43

Facilitated Diffusion vtransports large solute molecules from hypertonic to hypotonic solution v. Doesn’t require energy v. Through protein channels

PROTEIN CHANNELS • PROTEINS THAT ARE IN THE CELL MEMBRANE & HAVE A PORE FOR MATERIALS TO CROSS

Proteins Are Critical to Membrane Function

Active Transport v. Solute molecules materials from hypotonic to hypertonic solution v. Requires energy or ATP v. Through protein channels

EXOCYTOSIS • MOVING BULK SOLUTE & SOLVENT OUT OF CELL • REQUIRE ENERGY • USE VESICLES

Exocytosis Exocytic vesicle immediately after fusion with plasma membrane. 49

Endocytosis -Large or bulk molecules brought into the cell -require energy -use vesicles

Pinocytosis -bringing in bulk amount of liquid -most common form of endocytosis

Example of Pinocytosis pinocytic vesicles forming mature transport vesicle Transport across a capillary cell (blue). 52

Phagocytosis -Used to engulf large particles such as food, bacteria, etc. into cell (form of endocytosis) -Called “Cell Eating”

TAB 1 - HYPERTONIC • DRAW A CELL that has a 10% Na. Cl (salt) solution in an ENVIRONMENT with a 15% salt solution. COLOR the cell yellow and the environment light blue. In RED INK, write the percent of water inside and outside the cell. Use RED INK, and draw arrows showing the direction of movement of water into or out of the cell.

TAB 2 - ISOTONIC DRAW A CELL that has a 10% Na. Cl (salt) solution in an ENVIRONMENT with a 10% salt solution. COLOR the cell yellow and the environment light blue. In RED INK, write the percent of water inside and outside the cell. Use RED INK, and draw arrows showing the direction of movement of water into or out of the cell.

TAB 3 - HYPOTONIC DRAW A CELL that has a 6% Na. Cl (salt) solution in an ENVIRONMENT with a 3% salt solution. COLOR the cell yellow and the environment light blue. In RED INK, write the percent of water inside and outside the cell. Use RED INK, and draw arrows showing the direction of movement of water into or out of the cell.

INSIDE THE FOLDABLE- NOT ON THE BACK OF THE TAB In SECTION 1, bullet and answer each of the following questions about HYPERTONIC solutions: In HYPERTONIC solutions, water moves _______ the cell. Hypertonicity causes cells to ______. Plants cells _____ water and start to _W_ ___ ___. The process of water moving out of a cell is called P_____.

INSIDE THE FOLDABLE- NOT ON THE BACK OF THE TAB In SECTION 2, bullet and answer each of the following questions about ISOTONIC solutions: ____ cells need isotonic solutions to be at homeostasis. Water DOES or DOES NOT stop moving. Cells reach a point called Dynamic _______ in isotonic solutions. Equal amounts of water are ______ and _____ the cell.

INSIDE THE FOLDABLE- NOT ON THE BACK OF THE TAB In SECTION 3, bullet and answer each of the following questions about HYPOTONIC solutions: In HYPOTONIC solutions, water moves _____ a cell. Animal cells _____ in size and _____ or lyse in these solutions Bursting of cells is called C_____. ______ cells need this tonicity to be at homeostasis. _________ results from water inside a plant cell pushing the cell membrane out against the plant’s cell wall. 59

CORRECT YOUR ANSWERS! In SECTION 1, bullet and answer each of the following questions about HYPERTONIC solutions: In HYPERTONIC solutions, water moves OUT OF the cell. Hypertonicity causes cells to SHRINK. Plants cells LOSE water and start to WILT. The process of water moving out of a cell is called PLASMOLYSIS.

CORRECT YOUR ANSWERS! In SECTION 2, bullet and answer each of the following questions about ISOTONIC solutions: ANIMAL cells need isotonic solutions to be at homeostasis. Water DOES NOT stop moving. Cells reach a point called Dynamic EQUILIBRIUM in isotonic solutions. Equal amounts of water are ENTERING and EXITING the cell.

CORRECT YOUR ANSWERS! In SECTION 3, bullet and answer each of the following questions about HYPOTONIC solutions: In HYPOTONIC solutions, water moves INTO a cell. Animal cells INCREASE in size and BURST or lyse in these solutions Bursting of cells is called CYTOLYSIS. PLANT cells need this tonicity to be at homeostasis. HYDROSTATIC PRESSURE results from water inside a plant cell pushing the cell membrane out against the plant’s cell wall.

OSMOSIS & DIFFUSION IN AN EGG Objective: In this investigation, you will use a fresh egg to determine what happens during osmosis and diffusion across membranes. 63

EACH ROW WILL BE ONE GROUP! Here’s what you need: • BEAKER • EGG • EYEGLASS • TAPE • SHARPIE 64

DAY 1 1. Label the beaker with your lab group and the word “vinegar. ” 2. Determine the mass of your egg using the balance & record it in the data table. 3. Carefully place the raw egg into the jar & cover the egg with vinegar. 4. Cover the top of the beaker with an eyeglass.

EGG LAB DAY 2 1. Remove the eyeglass and pour off the vinegar. 2. CAREFULLY remove the egg and dry it with a paper towel. 3. Record the size and appearance of your egg in the data table. 4. Determine the mass of the egg by placing it on a balance and record the value in the data table.

DAY 2 (cont. ) 5. Clean and re-label your beaker with your lab group and “ water. ” 6. Carefully place the egg into the jar and cover it with distilled water. 7. Cover the beaker with an eyeglass. 67

EGG LAB DAY 3 1. Remove the eyeglass and pour off the distilled water. 2. CAREFULLY remove the egg and dry it with a paper towel. 3. Record the size and appearance of your egg in the data table. 4. Determine the mass of the egg by placing it on a balance and record the value in the data table.

DAY 3 (cont. ) 5. Clean and re-label your beaker with your lab group and “syrup. ” 6. Carefully place the egg into the jar and cover it with clear syrup. 7. Cover the beaker with an eyeglass. 69

DAY 4 1. Remove the eyeglass. CAREFULLY remove the egg rinse the excess syrup under slow running water. 2. Pat the egg dry with a paper towel. 3. Record the size and appearance of your egg in the data table. 4. Determine the mass of the egg by placing it on a balance and record the value in the data table. 5. Clean up your work area and put away supplies. (THROW THE CUP AWAY)