Macromolecules Goal Know the structure and function of all 4 macromolecules

Macromolecules : The Molecules of Life Within cells, small organic molecules called monomers are joined together to form larger molecules, known as Macromolecules. Each cell has thousands of different kinds of macromolecules. Macromolecules vary among cells of an organism, vary more within a species, and vary even more between species.

Function: What do macromolecules do? Carbohydrates - short term energy storage; structure of some organisms Lipids - (also known as fats) - long term energy storage Nucleic Acids (DNA and RNA) - the instructions the cell uses to build proteins Proteins (Polypeptides): The highly variable macromolecules that make each organism unique

Carbohydrates Sugars & Starches Used for energy in all organisms and for structure in plants.

Sugars Function: Monosaccharides serve as a major fuel for cells and as raw material for building molecules Monosaccharides have molecular formulas that are usually multiples of CH2O – 1:2:1 ratio Glucose is the most common monosaccharide Structure: though often drawn as a linear skeleton, in aqueous solutions they form rings

LE 5-4 Linear and ring forms Abbreviated ring structure

Monosaccharides (simple sugars)= monomer of carbohydrates Mono- = one • Glucose (C6H12O6) = sugar used as an energy source in all cells. • Other Examples: Fructose (Fruit sugar) & Galactose (Milk sugar)

Disaccharides (sugars) = 2 monosaccharides linked together. Di- = two Examples: Lactose (milk sugar) & Sucrose (table sugar)

Storage and Structure Polysaccharides 3 or more monosaccharides linked. Poly- = Many Glycogen = Used as energy storage in animals. • Cellulose = Used to form the cell wall of plants. Chitin- is found in the exoskeleton of arthropods and the cell walls of many fungi

Storage Polysaccharides Starch, a storage polysaccharide of plants, consists entirely of glucose monomers Plants store surplus starch as granules within chloroplasts and other plastids

Starch: a plant polysaccharide LE 5-6a Chloroplast Starch 1 µm Amylose Amylopectin Starch: a plant polysaccharide

Cellulose microfibrils in a plant cell wall LE 5-8 Cellulose microfibrils in a plant cell wall Cell walls Microfibril 0.5 µm Plant cells Cellulose molecules b Glucose monomer

Enzymes that digest starch by hydrolyzing alpha linkages can’t hydrolyze beta linkages in cellulose Cellulose in human food passes through the digestive tract as insoluble fiber Some microbes use enzymes to digest cellulose Many herbivores, from cows to termites, have symbiotic relationships with these microbes

Used for long-term energy storage. Lipids (fats) Steriods Used for long-term energy storage.

Lipids are a diverse group of hydrophobic molecules Lipids are the one class of large biological molecules that do not form polymers The unifying feature of lipids is having little or no affinity for water Lipids are hydrophobic becausethey consist mostly of hydrocarbons, which form nonpolar covalent bonds The most biologically important lipids are fats, sterols and phospholipids.

When phospholipids are added to water, they self-assemble into a bilayer, with the hydrophobic tails pointing toward the interior The structure of phospholipids results in a bilayer arrangement found in cell membranes Phospholipids are the major component of all cell membranes

LE 5-14 WATER Hydrophilic head Hydrophobic tails WATER

Steroids Considered lipids because they are hydrophobic!! Consist of 4 fused rings Cholesterol is a steroid

DNA – your genetic code RNA – used to make proteins Nucleic Acids DNA – your genetic code RNA – used to make proteins

Nucleotide = monomer of nucleic acids. Nucleotide has 3 parts: - phosphate - 5-carbon sugar - nitrogen base.

DNA & RNA = Polymers of nucleic acids DNA – di=2 (α-helix) carries the information on how to make proteins. Mostly 2 strands ( 1 found in viruses) RNA is directly involved in making proteins.( mostly 1 , two found in viruses )

Proteins The major building block in living things. Muscles, enzymes, antibodies, cell structure

Proteins have many structures, resulting in a wide range of functions Proteins account for more than 50% of the dry mass of most cells Protein functions include enzymes*,structural support, storage, transport, cellular communications, movement, and defense against foreign substances Different functions=different shapes

Structure of Proteins Protein = Polypeptide (polymer) comprised of monomers (amino acids). There are 20 different amino acids. Amine Group (NH2)-Basic Carboxylic Acid Group (COOH) – Acidic The center asymmetrical carbon is called the alpha carbon. The R group (think random) is variable for each amino acid! Also called the side chain.

Four Levels of Protein Structure Primary structure of a protein is its unique sequence of amino acids. Secondary structure, found in most proteins, consists of coils and folds in the polypeptide chain. The sequence of amino acids converts into 1 of 2 forms α-helix β-pleated sheets

1’ and 2’ Levels Protein Structure

Tertiary structure is determined by interactions among various side chains (R groups) Quaternary structure results when a protein consists of multiple polypeptide chains Not found in all proteins Same bonds/interactions as tertiary level

Tertiary & Quaternary Levels

Protein Denaturation

Protein Denaturation Denaturation Structure & Function Protein unravels and loses its native conformation Structure & Function Change in the protein’s structure = loss of function Denaturation occurs: Organic solvent Any chemical that disrupts the tertiary structure Heat (excessive)

R E V I W

Macromolecules Macromolecule Function Structure Carbohydrate Lipid Nucleic Acids Proteins

Sample MC Which molecule stores the largest amount of energy? A. Fat B. Starch C. Protein D. Glycogen

Sample Question A molecule with the chemical formula C16H32O16 is probably a A) carbohydrate. B) lipid. C) protein. D) nucleic acid. E) hydrocarbon.

Sample MC Amino acids are the building blocks of Proteins Lipids Carbohydrates Nucleic Acids

Sample MC Which polymer carries genetic information? Protein Lipid Carbohydrate Nucleic Acid

Sample MC Unlike carbohydrates and fats, proteins contain _____. A) nitrogen B) carbon C) hydrogen D) oxygen

Sample MC . Which of these elements is NOT part of a carbohydrate molecule? A) hydrogen B) oxygen C) carbon D) magnesium