CHAPTER 5 Biological compounds play an important role in life processes

Most molecules of a cell are carbon based These “biomolecules”- backbones of carbon atoms bonded to one another – called “organic molecules”, can be gigantic in size Carbon+hydrogen – “hydrocarbons”-methane (CH³)-in natural gas

Functional group – group of atoms within a molecule that interacts in a predictable way Carbon skeleton + attached functional group determines the properties of an organic molecule Hydroxyl group – hydrophilic: attracts water molecules Hydrophobic water avoiding molecules

Monomer - Small building block of a larger molecule Polymer – straight chain of monomers, about a total of 50 in number  Carbohydrates  Lipids  Proteins  Nucleic Acids Protein that makes up a spider’s web

Dehydration Reaction or Dehydration Synthesis – two monomers bond to each other, making a polymer chain longer, The Hydroxyl group(OH) of one monomer reacts with the Hydrogen(H) atom from another monomer.The reaction releases a water molecule.

Hydrolysis - Cells break bonds between monomers by adding water to them Water (hydro) is used to break down( lysis ) a molecule

Inorganic compounds no carbon exception - carbon dioxide, calcium carbonate, examples - water, salts

CARBOHYDRATES – “energy source”  Organic compound made up of 1 carbon :2 hydrogen:1 Oxygen Molecular formula CH2O Ring shaped carbon skeleton Monosaccharide – simple sugars with 1 sugar unit : glucose(main fuel supply for cells), fructose Disaccharide – “double sugar”: sucrose Glucose Polysaccharide – long polymer chains,complex carbohydrates : starch Glycogen – animal cells, stored in liver Cellulose – plant cell walls

LIPIDS (FATS) – Three carbon backbone called “glycerol” attached to 3 “fatty acids”which contain long hydrocarbon chains Some solid at room temperature Oils – liquid at room temperature Function – stores energy, cushions organs, insulation “Saturated fat” – all three fatty acid chains contain the maximum possible number of hydrogen atoms : animal fats,butter,lard “Unsaturated fat” – less than the maximum number of hydrogen atoms in one or more of it’s fatty acid chains : corn oil, olive oil

Cholesterol animal products like butter and meat buildup of deposits that narrow arteries ;leads to heart attacks and strokes

Steroids – lipid molecule in which the carbon skeleton forms four fused rings. While all steroids have the core of 4 rings, they differ in the kinds and locations of functional groups Circulate in the body as chemical signals

Nucleic Acids carbon, hydrogen, oxygen, phosphorous, nitrogen DNA(Deoxyribonucleic Acid)- transmits genetic information that is passed from one generation to the next- double helix RNA (Ribonucleic Acid)

structure long chains of repeating units called NUCLEOTIDE (a) 5 carbon sugar - deoxyribose (b) phosphate group © nitrogenous base - adenine=thymine; cytosine=guanine

Structure of RNA single strand each nucleotide (a) 5 carbon sugar - ribose (b) phosphate group © nitrogenous bases - adenine=uracil ; cytosine=guanine

PROTEIN from the Greek word meaning “first place”- suggests the importance of this class of polymers. Each one has a unique 3-dimensional structure that corresponds to a specific function Texture of animals coat Powerful muscles Food value in nuts Responsible for the day to day function of organisms Example – hair,fur,muscles control chemical reactions in the cell

Protein is a polymer constructed from a set of 20 kinds of monomers called “amino acids” Each amino acid consists of a central carbon atom bonded to 4 partners : amino group, carboxyl group,hydrogen atom 4 th group is a “side group” or “R-group” is responsible for the particular chemical properties of each amino acid. hydrocarbon

Cells create proteins by linking amino acids together in a chain called a “polypeptide” Each link is created by the dehydration reaction between the amino group of one amino acid and the carboxyl group of the next amino acid in the chain. Proteins are composed of one or more polypeptide chains,usually at least 100 amino acids in length

Protein Shape – a functional protein consists of one or more polypeptides precisely twisted, folded,and coiled into a unique shape Influenced by the surrounding environment Unfavorable change in the environment (pH,temperature) can cause the protein to unravel.This is called “denaturation ”

The chemical reactions within a cell requires “activation energy”(start-up energy) Provided indirectly by “catalysts”(compounds that speed up a chemical reaction without themselves changing) “Enzymes” or “organic catalysts” are specialized proteins example - maltase acts on maltose Enzymes lowers the energy requirement barrier so that the reaction can proceed at normal cell temperatures

Enzyme action - Lock and key on surface of the protein is the active site substrate molecule fits the active site forms a temporary enzyme-substrate complex - Lock and Key mechanism

Induced Fit Mold enzyme, not with rigid shape, changes slightly so that the it can fit snugly around the substrate

Factors affecting the Rate of Enzyme reaction small amount of enzyme for large amounts of substrate rate of reaction dependent on enzyme:substrate concentration coenzymes may be required sometimes

allow optimal reactions at normal temperature-36* works best at certain pH -7 ex. Pepsin in stomach acts only when HCL is present