Unit 4: The chemistry of life Macromolecules Unit 4: The chemistry of life NCSCOS 2.01 TSWBAT Compare and contrast the structure and functions of the following organic molecules: carbohydrates, proteins, lipids, nucleic acids

Organic Molecules Organic molecules are the chemicals of life, compounds composed of more than one type of element, that are found in, and produced by, living organisms. The feature that distinguishes an organic from inorganic molecule is that organic contain carbon- hydrogen bonds, whereas inorganic molecules do not. The four major classes of organic molecules include carbohydrates, proteins, lipids and nucleic acids.

Carbohydrates = sugars Monomer of a carbohydrate = Monosaccharide Primary energy source inside cells; “quick” energy Ex: Glucose ( C6H12O6)

Complex sugars Disaccharide = two or simple sugars bonded together Ex: maltose, sucrose

Even more complex sugars Polysaccharides = long chains of monosaccharides linked together Primarily used for energy storage Cellulose and chitin are used for structural support

Functions of polysaccharides Starch: stores energy in plants Plants make glucose (monomer) during photosynthesis, and the glucose molecules join together to form starch Cellulose: structural support in plants Compose cell wall Glycogen: stores energy in animals Chitin : composes the exoskeletons of insects and makes up cell walls of fungi

Lipids = fats, oils, waxes Make up cell membranes Long term energy molecules Monomers= Fatty acids and glycerol

Lipids = fats, oils, waxes This large fat molecule is called a triglyceride It is a saturated fat

Saturated vs. Unsaturated Fats The difference is the whether or not single or double bonds exist in the fatty acid chain

Concentration fatty acids

Function and Examples Fats Insulation, Cushion, Long-term energy storage Phospholipids Make up cell membrane Steroids Chemical Messengers (hormones, cholesterol)

Cholesterol is another example of a lipid Cholesterol is another example of a lipid. Other lipids include some hormones such as testosterone, and estrogen cholesterol Estrogen Testosterone

Proteins Varied functions include: provide raw materials for cell structure, assist in transport, catalyze chemical reactions Polymer: Polypeptide/Protein Monomer: Amino Acids

Peptide bonds link amino acids to build polypeptides A peptide bond holds the two amino acids together to form a polypeptide chain

Polypeptides

Examples of Proteins Enzymes: speed up chemical reactions by lowering activation energy Insulin: hormone that controls the level of glucose in the blood Hemoglobin: protein molecule in red blood cells that transports oxygen from the lungs to all the cells of the body

Enzymes are special proteins They help speed up chemical reactions = catalysts Each kind of enzyme will help only one chemical reaction occur Starch (amylose) amylase maltose

Nucleic Acids Polymer: Nucleic Acid Monomer: Nucleotide Ex: DNA, RNA Nucleotide has three parts Sugar Nitrogen Base Phosphate Group

Examples DNA: stores hereditary information RNA: Transmits hereditary information

DNA Structure The order and the sequence of the N- bases is the genetic code. Weak Hydrogen (H) bonds between the N- bases hold the double helix together The shape of the DNA polymer is called a double helix