The Cell Membrane Cell Membrane Basics Function Controls

The Cell Membrane

Cell Membrane Basics • Function: Controls the passage of materials into and out of a cell • Double layer of phospholipids (bilayer)

Cell Membrane Basics • Function: Controls the passage of materials into and out of a cell • Double layer of phospholipids (bilayer) • Semi-Permeable: only some materials may enter/exit

Phospholipid Composition • 3 Parts phosphate Polar Head • 1) Phosphate Group • 2) Glycerol glycerol Nonpolar Tails • 3) Two chains of fatty acids • Arrangement: – Outside: Polar heads – Inside: Nonpolar Tails Fatty acids

Phospholipid Bilayer

Cell Membrane Contents 1) Cholesterol: strength & flexibility 2) Carbohydrates: identification 3) Various Proteins

Cell Membrane Contents glucose Protein channel glucose 1) Cholesterol: strength & flexibility 2) Carbohydrates: identification 3) Various Proteins

Membrane Proteins • Randomly scattered through the bilayer • Various Functions – Cytoskeleton: internal support – Protein channels: allow objects to pass – Enzymes: speed up chemical reactions – Markers: cell recognition; fight disease

Kobe Kuiz 1) 2) 3) 4) Name the 3 parts to a phospholipid? Which part(s) make up the head of a phospholipid? Which part(s) make up the tails of a phospholipid? Which part of phospholipid always seems to be in contact with a watery environment? Why? 5) Draw and label the components of the cell membrane. 6) Which membrane protein supports the cell membrane? 7) Which membrane protein allows materials to pass through?