Biomolecules The Chemical Building Blocks of Life

The Chemistry of Carbon Organic molecules contain carbon Carbon’s four valence electrons allow it to form up to four covalent bonds Hydrocarbons consist only of C and H –Propane CH 8 It can easily bond to itself and form long chains –Linear- Cyclic- Branched

Functional Groups Chemical properties and reactivity are a result of functional groups Functional groups maintain chemical properties no matter where they occur Polar molecules are hydrophilic Nonpolar molecules are hydrophobic The degree to which organic molecules interact with water affects their function Hydroxyl group (-OH) is one of the most common functional groups, it will make a molecule water soluble

Macromolecules – The Sum of the Parts Many complex biological activities require large macromolecules Macromolecules are polymers built by linking together small subunits called monomers –Proteins are polymers of amino acids –Nucleic acids are polymers of nucleotides –Starches are polymers of simple sugars

Condensation It’s not just for the water cycle anymore Macromolecules are constructed by covalently bonding monomers by condensation reactions where water is removed from the functional groups of the monomers Dehydration synthesis (water is removed) A hydroxyl (-OH) from one monomer and a hydrogen (-H) from another are removed Anabolic reaction

Hydrolysis Hydrolysis is the reverse of condensation Results in the break down of polymers Hydration reactions add water and break bonds releasing energy animation

Macromolecules Perform complex tasks with precision Basic structure and function of each family similar in all organisms (bacteria – humans)

Families of Biomolecules Carbohydrates Lipids Proteins Nucleic Acids

Basic Function Carbo’sLipidsN. AcidsProteins Energy Storage Structure Long term storage Insulation Protection Inheritance Blueprint for metabolism Catalysts Hormones Structure Starch Glycogen Glucose Sucrose Cellulose Lipid Fats Oils Waxes DNA RNA ATP Proteins Enzymes

Carbohydrates How Sweet It Is! General formula (CH 2 O) n Simple sugars or large molecules made of sugar monomers Monosaccharides (monomer) are covalently linked by condensation reaction to form polysaccharides (polymers)

Sugars Monosaccharides –Five carbon: Ribose –Six carbon: glucose and fructose Disaccharides –Sucrose –Lactose Polysaccharides –Starch –Cellulose –Glycogen

Polysaccharides Three Types Glycogen – animal storage product that accumulates in the liver - Highly branched GlucoseGlycogenglucosebloodstream Starch – plant energy storage - Helical - Easily digested by animals through hydrolysis

Cellulose Polysaccharide found in plant cell walls For humans cellulose is indigestible and forms dietary fiber Made up entirely of β glucoses –Structure is constrained into straight microfibrils Not an energy source for animals Chitin – insect exoskeletons

So what’s the difference between condensation and hydration reactions? animation

Lipids Long-term energy storage Generally insoluble in water –nonpolar –hydrophobic Structural components of cells (phospholipids) Cellular messengers (hormones)

More FAT Triglycerides are composed of three fatty acids covalently bonded to one glycerol molecule Fatty acids are composed of CH 2 units and are hydrophobic Fatty acids can be saturated (all single bonds) or unsaturated (one or more double bonds) A fat (mostly saturated) is solid at room temp., while an oil (mostly unsaturated) is liquid at room temp.

Glycerol is a molecule with three carbons in a row, each with a hydroxide group Fatty acid chains are hydrocarbons that is, they are composed of mostly carbons and hydrogens. This is a molecule that is VERY hydrophobic. When glycerol combines with the fatty acid chains it forms a carboxyl group between them They link by the loss of a water molecule. Carbon can bond to four different substances, but sometimes it will share more than one pair of electrons. animation video

Phospholipids Important structural component of cell membranes Phosphate group (head) is polar and water soluble (hydrophilic) Two fatty acid tails are hydrophobic This allows the phospholipids to form bilayers and membranes

Other Lipids Steroids –Insoluble in water –Built around a four ringed skeleton Cholesterol –Component for animal cell membranes –Formation of myelin sheath covering nerves Hormones –Chemical messengers Waxes –Many fatty acids linked to a long backbone –Waterproofing in plants, ears, beehives overview

Proteins 50% dry weight of body Mammal cell contains 10,000 proteins Enzymes (regulate chemical reactions) Structural elements (cell membrane, muscles, ligaments, hair, fingernails) Carriers (regulate what goes into/out of cells) Send and receive messages (hormones) Movement

Building Blocks of Proteins Amino Acids Amino acids (monomers) are linked together to form proteins (polymers) –Each unique sequence of amino acids forms a different protein –All living things (even viruses) use the same 20 amino acids 20 different Amino Acids –Amino end (NH 2 ) –Carboxyl end (COOH) –Hydrogen –R group – variable component

Amino Acids Amino Acids are grouped by whether R- group is polar or non- polar Positively charged side chain Negatively charged side chains Polar but uncharged side chains Hydrophobic side chains Special cases

Protein Assembly AA’s are linked together by joining the amino end of one molecule to the carboxyl end of another Peptide bond forms a chain called a polypeptide as/aminocon.html

Protein Structure Primary structure –Specific linear sequence of AA’s in a polypeptide –Determined from code in inherited genetic material –Changes in primary structure can alter proper functioning of the protein

Hormone: Insulin Frederick Sanger (1940s, 50s), discovered the amino acid sequence of Insulin Causes cells to take up more glucose, and liver and muscle cells to create glycogen Diabetes is a deficiency of insulin

Carrier: Hemoglobin -Protein that carries oxygen to your cells -Iron an important co- factor, iron deficiency =anemia

Sickle Cell Disease

Spider silk: a structural protein Spider Silk Video

Enzyme: Salivary Amylase Hydrolyzes starch while chewing

Enzyme: Rubisco Catalyzes first step of carbon fixation in photosynthesis

Movement: Actin and Myosin

Secondary structure - the tendency of the polypeptide to coil or – pleat due to H-bonding between R- groups -  - helix,  -pleated sheet, or random coil

Tertiary structure - shape of entire chain; folded, twisted, or – globular - shape related to function and properties

Quaternary structure - more than one polypeptide chain

Nucleic Acids Polymers composed of monomer units known as nucleotides Information storage –DNA (deoxyribonucleic acid) Protein synthesis –RNA (ribonucleic acid) Energy transfers –ATP (adenosine tri-phosphate) and NAD (nicotinamide adenine dinucleotide)

Nucleotides Structure –Phosphate –Nitrogenous base  Purines (double-rings)  Adenine and Guanine  Pyrimidines (single-rings)  Cytosine, Thymine, and Uracil –Sugar – either ribose or deoxyribose  pentoses in ring form  Deoxyribose lacks one oxygen

Functions of Nucleic Acids DNA – Physical carrier of genetic information –Restricted to nucleus RNA – key component of protein synthesis –Messenger RNA (mRNA) – blueprint for construction of a protein –Ribosomal RNA (rRNA) – construction site where the protein is made –Transfer RNA (tRNA) – truck delivering the proper AA to the site of construction

The End