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Cell Membrane & Tonicity Worksheet Composition of the Cell Membrane & Functions The cell membrane is also called the PLASMA membrane and is made of a phospholipid BI-LAYER. The phospholipids have a hydrophilic (water attracting) HEADS and two hydrophobic (water repelling) TAILS. The head of a phospholipid is made of an alcohol and GLYCEROL group, while the tails are chains of FATTY ACIDS. Phospholipids can move SIDEWAYS and allow water and other NON-POLAR molecules to pass through into or out of the cell. This is known as simple PASSIVE TRANSPORT because it does not require ENERGY and the water or molecules are moving WITH the concentration gradient. SKETCH AND LABEL a phospholipid coloring the heads red and the tails blue. Another type of lipid in the cell membrane is CHOLESTEROL that makes the membrane more fluid. Embedded in the phospholipid bilayer are PROTEINS that also aid in diffusion and in cell recognition. Proteins called INTEGRAL proteins go all the way through
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Composition of the Cell Membrane & Functions The cell membrane is also called the PLASMA membrane and is made of a phospholipid BI-LAYER. The phospholipids have a hydrophilic (water attracting) HEADS and two hydrophobic (water repelling) TAILS. The head of a phospholipid is made of an alcohol and GLYCEROL group, while the tails are chains of FATTY ACIDS. Phospholipids can move SIDEWAYS and allow water and other NON-POLAR molecules to pass through into or out of the cell. This is known as simple PASSIVE TRANSPORT because it does not require ENERGY and the water or molecules are moving WITH the concentration gradient. SKETCH AND LABEL a phospholipid coloring the heads red and the tails blue. Another type of lipid in the cell membrane is CHOLESTEROL that makes the membrane more fluid. Embedded in the phospholipid bilayer are PROTEINS that also aid in diffusion and in cell recognition. Proteins called INTEGRAL proteins go all the way through the bilayer, while PERIPHERAL proteins are only on one side. Large molecules like PROTEINS or carbohydrates use proteins to help move across cell membranes. Some of the membrane proteins have carbohydrate PARTS attached to help cells in recognize each other and certain molecules. List 4 functions of the cell or plasma membrane: a. CELL SIGNALING b. SELECTIVE TRANSPORT c. EXCRETION OF WASTES d. STRUCTURAL SUPPORT Correctly color code and identify the name for each part of the cell membrane. Letter Name/Color Letter Name/ Color __ A ___ Phospholipid bilayer (no color) __ H ___ Peripheral protein (red) __ B ___ Integral protein (pink) __ I ____ Cholesterol (blue) __ F ___ Fatty acid tails (orange) __ C ___ Glycoprotein (green) __ G ___ Phosphate heads (yellow) __ E ___ Glycolipids (purple) Match the cell membrane structure or its function with the correct letter from the cell membrane diagram. Letter Structure/Function Lette r Structure/Function __ G ___ Attracts water __ F__ Repels water __ I ___ Helps maintain flexibility of membrane _G&F Make up the bilayer
Involved in cell-to-cell recognition __ B__ Help transport certain materials across the cell membrane
Transport Requiring Energy What type of transport is represented by the following picture? ACTIVE What energy is being used? ATP In which direction (concentration gradient), is the movement occurring? AGAINST Color the internal environment of the cell yellow. Color and Label the transport proteins red and the substance being moved blue. One type of active transport is called the SODIUM-POTASSIUM pump which helps muscle cells contract. This pump uses PROTEINS to move ions AGAINST the concentration gradient. The protein that is used to pump the ions through is called a TRANSMEMBRANE (INTEGRAL) protein and it changes its SHAPE to move the ions across the cell membrane. Label and color the carrier proteins red and the ions green. TONICITY AND OSMOSIS Part I – Fill in the blanks. A SOLVENT is a fluid in which a substance is dissolved. A SOLUTE is a substance dissolved in a solvent. A SOLUTION is a combination of solute and solvent. The process by which water diffuses across a membrane called OSMOSIS Part II – Look at the solutions illustrated above and fill in the blanks.