1.7 – 1.10 Carbohydrates, Lipids, Proteins, & Nucleic Acids Organic Compounds 1.7 – 1.10 Carbohydrates, Lipids, Proteins, & Nucleic Acids

Carbohydrates Examples Sugars (glucose, sucrose) Starch Cellulose (plants) Glycogen (animals)

Carbohydrates – Structural Formula of the monomer Made up of carbons, hydrogens, & oxygens in a 1:2:1 ratio. Carbon Hydrate (water)

Carbohydrates – Monomers Monomer = Monosaccharide (also gets called “simple sugar”) Contain 3-7 carbons (often in a ring/ but can be straight chain) Common Examples: Glucose (C6H12O6) Fructose (C5H10O5)

Carbohydrates Dimer (Two simple sugars combined) = disaccharide Ex. – Sucrose (made of glucose & fructose) Lactose (made of galactose & glucose) Maltose (made of 2 glucoses) ** Formed by dehydration synthesis. ** Broken down by hydrolysis.

Carbohydrates Polymer (Many simple sugar units combined) = polysaccharide Ex. – starch, glycogen, cellulose Also formed by dehydration synthesis & broken down by hydrolysis.

Cellulose & Humans Cellulose is the major component of the rigid cell walls of plant cells; it is a linear polysaccharide with repeating glucose monosaccharide subunits

Cellulose & Humans The linkage between the glucose molecules in cellulose is called a beta acetal linkage. Humans are unable to digest cellulose because the appropriate enzymes to breakdown the beta acetal linkages are lacking. However, cows, horses, sheep, goats, and termites have symbiotic bacteria in the intestinal tract. These symbiotic bacteria possess the necessary enzymes to digest cellulose in the GI tract, even though the animals, themselves, do not have the enzyme.

Carbohydrates Functions * Short-term Energy source for organisms (glucose = important energy source) - Structural molecules (cellulose found in rigid cell walls) - Act as receptors for chemical messengers (hormones) on cell membranes - Can have long term energy storage uses (cellulose in plants, & glycogen in animals)

Carbohydrates Relating Structure to function Glucose is easily/readily broken down in living things (during a process called cellular respiration) to release energy. It’s structure allows it to easily be broken down into carbon dioxide & water waste products. For the structures in organisms (cellulose in plant cells), it is a large, rigid structure with many straight repeating subunits that provide support.

Lipids – Common names/examples Fats, oils & waxes

Lipids No single specific “monomer name” Building blocks of many fats = fatty acid chains & glycerol Simple fat = Triglyceride (3 fatty acids & glycerol) No dimer/polymer. Made up primarily of carbons & hydrogens with a few oxygens.

Lipids Structure of fatty acid tails Long hydrocarbon chain with a carboxylic acid group at one end.

Lipids Other Information: Can classify them as unsaturated vs. saturated 1 or more Double bonds Oily Liquids @ room temp All Single bonds Solids @ room temp

Lipids in Water Lipids are non-polar; this makes them hydrophobic (they don’t “like” water) When they are put into water, they tend to form either a bilayer or a micelle

Lipids Functions * Long term energy storage * Structural component of cell membranes - Important signaling molecules - Used as insulation in some organisms

Lipids Two other important examples: Phospholipids & Cholesterol 2 fatty acids & a phosphate group Make up cell membranes Part of membranes in animals Imp. Building block of hormones, etc.

Lipids Why is the phosphate head hydrophilic? Why are the fatty acid tails hydrophobic?

Lipids Relating Structure to Function Hydrophobic parts kept away from water; hydrophyllic parts in contact with water – allows many types of molecules to travel through the membrane

Proteins Examples Fibrous proteins: actin, collagen, elastin, keratin… Globular proteins: albumins, hemoglobin Membrane proteins: hydrolases, transferases

Proteins Building Bocks = Amino Acids (contain C, H, O, & N; 2 examples have S) There are only 20 different amino acids, but proteins can be made of amino acid chains that are 1000s of amino acids long.

Amino Acids (Proteins) The R group is a variable group (there are 20 different R groups). It is the R group that determines the characteristics (solubility/polarity) of the amino acid & leads to specific folding patterns in the protein.

Proteins Dimer (made of 2 amino acids) = dipeptide The amino acids are joined by a peptide bond; (dehydration synthesis) When several peptide bonds form, a polypeptide forms (polymer) which usually inc. up to 50 amino acids. Proteins involve a complex combination of polypeptides and other molecules, as well as complex folding.

Proteins Functions - Enzymes that catalyze (speed up) reactions - Structural & Mechanical functions (muscles, hair, nails) - Cell signaling, Immune response, cell division - Component of cell membranes & help with transport of materials.

Protein Folding/Structure Primary Structure – the amino acid order of the protein. Example: gly-gly-ser-ala - Four amino acids: glycine, glycine, serine, & alanine There are only 20 different amino acids, but proteins can be made of amino acid chains that are 100s of amino acids long.

Protein Folding/Structure Secondary Structure – The twists and folds of the amino acid chain (primary structure) Can form alpha helices or beta sheets

Protein Folding/Structure Tertiary Structure – A more complex, globular folding of secondary structures. It is dictated by the location of nonpolar amino acids in the primary sequence. These amino acids will seek the inside of the fold – to get away from the water.

Protein Folding/Structure Quaternary Structure – The structure when two or more tertiary structures combine.

Nucleic Acids Macromolecules that are made of long chains of nucleotides. A nucleotide: Nucleic acids contain the following atoms: C, H, N, O, and P

Nucleic Acids 2 major examples: DNA & RNA

DNA vs. RNA (the sugar) Both DNA & RNA contain a 5 carbon sugar: DNA = deoxyribose RNA = ribose Ribose has 1 additional –OH group.

DNA Nucleotides There are 4 different types of nucleotides in DNA: Phosphate DNA Nucleotides Nitrogen base Deoxyribose There are 4 different types of nucleotides in DNA: Adenine (A) Cytosine (C) Guanine (G) Thymine (T) The part of the nucleotide that differs is the NITROGEN BASE.

Nucleic Acids Functions - Source of genetic information (chemical link between generations) - Determine the sequence of amino acids when proteins are formed Found as chromosomes in the nucleus of a cell; also in viruses & bacteria (but these don’t have nuclei), & in some cell parts besides nucleus

Variations in Organisms Nucleic acids lead to variations in organisms based on the order of the nucleotides. This will code for how proteins get made, which eventually leads to the different traits an organism gets

Differences: DNA vs. RNA Double helix Nitrogen bases: Adenine, Cytosine, Guanine, Thymine Sugar = Deoxyribose Found in nucleus of cell RNA Single-stranded Nitrogen bases: Adenine, Cytosine, Guanine, Uracil Sugar = Ribose Found in nucleus and cytoplasm of cell