Lipids & Cell Membranes Honors Biology
Objectives Construct and revise an explanation based on evidence for how carbon, hydrogen, and oxygen from sugar molecules may combine with other elements to form amino acids and/or other large carbon-based molecules. Plan and conduct an investigation to provide evidence how feedback mechanisms maintain homeostasis.
Lipids
Recall: Macromolecules BIG biological molecules Made of smaller parts Monomers Carbon-based (organic) Carbohydrates Nucleic acids Proteins Lipids
Lipids Monomer? Used for: Examples: Found in: Glycerol head Fatty acid tail Used for: Long term energy storage Insulation Major component of membranes Signaling molecules and hormones Examples: Fats, oils, waxes Found in: All the good tasting foods
Cell Membranes
Cellular Biology Review All cells have cell membranes Some cells (eukaryotes) have membranes surrounding organelles Example: nucleus All cells need to import and export molecules in order to function properly and maintain homeostasis
Cell Membrane Function: Homeostasis! Regulate passage of nutrients, wastes, gases, and water into and out of cell Selectively permeable – “picky” about what passes Separate cell from the environment Allow cells to communicate with other cells via receptors on the surface
Cell membranes are fluid mosaics of lipids and proteins
Structure of the Cell Membrane Made of phospholipid bilayer Phosphate (hydrophilic) “head” Lipid (hydrophobic) “tail” Phospholipid bilayer
Structure of the Cell Membrane Protein channels Allow large molecules to pass through Protein channels
Structure of the Cell Membrane Receptor Protein Receives messages from outside the cell Cell communication is key for homeostasis! Receptor Protein
Structure of the Cell Membrane Cholesterol Lipids that prevent freezing Helps membrane remain fluid (flexible) Cholesterol
Structure of the Cell Membrane Integral proteins Help with cell signaling Act in cell recognition (“name tags”) Integral Protein
Structure of the Cell Membrane Peripheral proteins Give structure to cell Cytoskeleton can anchor Peripheral Protein