10/15/13
Objective: What are the properties of Lipids?
Chapter 5: The Molecules of Life
Do Now: What can happen to sugar if not used for energy?
Lipids
• lipids: class of compounds that are hydrophobic (water-fearing) and nonpolar– Made of glycerol and
fatty acid– Part of cell membrane– store energy
Fatsfats(triglyceride):) made of glycerol attached to 3 fatty acids(long
hydrocarbon chains)– Solid or liquid– Fatty tissues cushion organs and provide body with insulation
• saturated fats: all fatty acid chains contain the maximum possible number of hydrogen atoms– All single bonds– Animal fats (solid at room temp)
• unsaturated: less than max. number of H atoms in one or more fatty acid chains
– Some double bonded– Most plant and fish oils
(liquid at room temp)
Steroids
steroids: carbon skeleton forms 4 fused rings– Different functional
groups attached to rings
• Examples: Cholesterol, Sex hormones
Cholesterol
• cholesterol: essential molecule found in cell membranes– Help maintain membrane
structure
Phospholipids
• Major part of cell membrane
5.4 Proteins
• protein: a polymer constructed from monomers called amino acids.– Ex: Enzymes, hormones,
cell receptors, immune defense
Protein Structure
• amino acid: monomer that consists of a central carbon atom bonded to four partners (carbon forms 4 bonds)- a carboxyl and amino group
• Polypeptide: chain of amino acids that make up a protein– Made by dehydration synthesis
Shape
• polypeptides are precisely twisted, folded, and coiled into a unique shape for each protein
• Shape of protein determines how it will function
Denaturation
• Denaturation: unfavorable change in pH, temperature, or other quality of the environment that causes the protein to unravel and lose shape– (ex. frying an egg;
albumin is egg white which turns from clear to white)
Enzymes
• enzymes: proteins that act as organic catalysts– Lowers activation energy
• pH and temp can affect function
Catalysts
• Catalysts: compounds that speed up chemical reactions
How Enzymes Work
• substrate - a specific reactant acted upon by an enzyme
the shape of the enzyme fits the shape of only particular substrate
• active site - where enzymes binds to substrate
Substrates are the reactants. Lactose is the substrate, lactase is the enzyme.
Enzyme Function
Describe what is occurring in the picture:
Enzyme Function
Nucleic Acids
• DNA: dexoyribose nucleic acid
• RNA: ribose nucleic acid
Top Related