SBI4U BIOCHEMISTRY Biological Macromolecules

Essential Questions: What are the 4 main types of biological macromolecules and what is their function within cells? How does the structure of each macromolecule contribute to their function within cells?

Carbon: The Central Atom What’s so special about ? The diversity of life relies on carbon!!! Virtually all chemicals of life are carbon based – called organic compounds. It can form four covalent bonds C-C bonds enable carbon to form a variety of geometrical structures (e.g., straight chains, branched chains, rings) Methane CH4 + CH2 Ethane C2H6 + C4 Benzene C6H6

Molecular Isomers: The same, yet different What’s so special about ? Carbon forms isomers! Isomer – an organic compound with the same molecular formula, but different structure Fructose (fruit sugar) Galactose (milk sugar) C6H12O6 Glucose (simple sugar) Example: C Metabolized by cells differently due to structure Structural isomers

Consider the following structures… Are these structures atoms, compounds?

What is the relationship between atoms, bonding and macromolecules? Bond together to form… Molecules Bond together to form… Macromolecules

Macromolecules and their subunits Monomer + = Polymer Macromolecule glucose glycogen smaller subunits that make up a polymer long chain of monomers

Macromolecules and their subunits Carbon Compounds include Which are made of which contain Carbohydrates Lipids Nucleic acids (e.g.,DNA/RNA) Proteins Simple sugars (e.g., glucose) Glycerol & 3 Fatty Acids Nucleotides Amino Acids Carbon, hydrogen, oxygen Carbon, hydrogen oxygen, nitrogen, phosphorus hydrogen, oxygen, nitrogen, 1 2 3 4 main function main function main function main function ENERGY STORAGE ENERGY STORAGE CATALYSIS & STRUCTURE /SUPPORT ENCODING HEREDITARY INFORMATION short-term long-term

Carbohydrates 1 2 3 4 Composition: C, H, and O atoms (1 : 2 : 1 ratio) Main Function: quick and short-term energy storage Composition: C, H, and O atoms (1 : 2 : 1 ratio) Two types: 1. Simple Carbohydrates (monosaccharides and disaccharides) 2. Complex Carbohydrates (polysaccharides) Carbon Compounds include Which are made of which contain Carbohydrates Lipids Nucleic acids Proteins Simple sugars (e.g., glucose) Glycerol & 3 Fatty Acids Nucleotides Amino Acids Carbon, hydrogen, oxygen Carbon, hydrogen oxygen, nitrogen, phosphorus hydrogen, oxygen, nitrogen, 1 2 3 4 main function ENERGY STORAGE short-term

Carbohydrates – Simple (glucose) Monosaccharides Carbohydrate molecule with 3-7 carbon atoms. (mono = one, saccharide = sugar) Broken down quickly in the body to release energy. e.g., GLUCOSE – hexose (six-carbon) sugar with 7 energy-storing C-H bonds C6H12O6 1 2 3 4 5 6 Primary source of energy used by all cells

Disaccharides Disaccharide: A compound composed of 2 monosaccharide subunits ex. lactose, maltose, sucrose Condensation/Dehydration Reaction: Process by which disaccharides are formed Hydrolysis Reaction: Process by which a disaccharide is split into 2 monosaccharides

Making & Breaking Carbohydrates monosaccharide + disaccharide (di = two) Condensation (dehydration) synthesis Hydrolysis Two important biochemical reactions

Carbohydrates – Complex (Polysaccharides) Main Function: quick and short-term energy storage Contain many units of glucose in long chains Examples: Starch, glycogen, cellulose, chitin Starch Granules (purple) in Potato Cells Starch = energy storage in plants

Carbohydrates – Complex (Polysaccharides) Glycogen (polymer) Glucose (monomer) Glycogen = energy storage in animals muscle liver Glycogen (red) in Hepatocytes (liver cells)

Carbohydrates – Complex (Polysaccharides) Cellulose fibers Cellulose = polysaccharide found in plant cell walls giving walls structure and strength Macrofibril Microfibril Chains of cellulose

Carbohydrates – Complex (Polysaccharides) What is the difference between starch and cellulose? Starch Cellulose

Make a Venn Diagram! Starch Cellulose

Glucose repeat units are facing the same direction Starch Cellulose Glucose repeat units are facing the same direction Each successive glucose unit is upside-down in relation to each of the glucose molecules that it is connected to Both polymers Same monomer (glucose) Weaker Structure Stronger (good for building) Enzymes to digest Cannot digest (no enzymes) Insoluble (fiber / roughage) Soluble