Unit One “Science Introduction & Cellular Function” “Molecules of Life”

Monomers and Polymers Organic Molecule – a molecule formed by living organisms that consist of a carbon backbone with other elements bonded to it All four categories of macromolecules, which are organic, are made from monomers that combine to form polymers Macromolecules – very large molecules that are necessary for the maintenance of the structure and function of the cell Monomer – a subunit or “train car” that when connected to others forms a polymer or “train”

Monomers and Polymers Polymer – a large molecule composed of many subunits (“train cars”) All four categories of macromolecules connect their monomers (subunits) in the same way: – “Dehydration Synthesis” – making polymers from monomers OH group is removed from one subunit and an H group is removed from the other subunit Both the OH and H groups together compose water (H 2 O); this is why this process is called “Dehydration” An enzyme (protein) is used to facilitate this reaction

Monomers and Polymers To breakdown a polymer the opposite of Dehydration Synthesis occurs and is called “Hydrolysis” – Hydrolysis – reducing a polymer to its monomer parts An OH and H group are added to opposite sides of a subunit, therefore causing the polymer to be broken into its monomer parts

Proteins Monomer = Amino Acid Polymer = Protein 20 common amino acids which differ by their functional group Amino Acids are linked by “Peptide Bonds” (a type of covalent bond), and are formed via Dehydration Synthesis Long chains of amino acids linked by Peptide Bonds are called “Polypeptides”

Proteins The way in which proteins function is determined by the shape of the protein, which in turn, is determined by what monomers bond with each other There are four levels of protein structure that determine functionality: – Primary – long chain – Secondary – long chain folds – Tertiary – long chain folds and twists – Quaternary – more than one polypeptide chain

Proteins Proteins can only function in a specific range in reference to temperature and pH If the temperature is too high, or the environment is too acidic (low pH), then the protein unfolds and no longer functions = “Denatured” Proteins are extremely important because they serve as the “local government”: they ensure the proper function of the cell Tertiary Proteins are Enzymes Enzymes act as catalysts, which govern cellular reactions

Proteins

Nucleic Acids Monomer = Nucleotide Polymer = Nucleic Acid (RNA & DNA) The 5 Carbon Sugars of each Nucleotide are linked by Phosphate Groups to form Polynucleotide Chains = RNA and DNA RNA is found in viruses, and both RNA and DNA are found in other species RNA is single-stranded DNA is double-stranded

Nucleic Acids Polynucleotide Chains (RNA and DNA) function is essentially that of a library: these macromolecules possess all the information necessary to both form an individual and maintain that individual throughout life

Nucleic Acids

Carbohydrates Monomer = Simple Carbohydrate Polymer = Complex Carbohydrate Carbohydrates purpose is to serve as an energy supply for cells, and in some cases (polysaccharides), to serve as a structural support to organelles in cells Simple Carbohydrates – Monosaccharides – one monomer/subunit, Glucose is an example C 6 H 12 O 6 – Disaccharides – two monomers/subunits linked together via dehydration reaction, Lactose is an example

Carbohydrates Complex Carbohydrates – Polysaccharides – long polymer chains; Starch, Glycogen, Chitin, and Cellulose Starch (plants) and Glycogen (animals) are storage macromolecules for energy when energy is not immediately needed by the organism’s cells Cellulose (plants) and Chitin (animals) are carbohydrate macromolecules that assist with structural support of organelles within the organism’s cells

Carbohydrates “Glucose”

Lipids Monomer = Fatty Acids and Glycerol Polymer = Lipid or “Triglyceride” Lipids are “Fats” They are not soluble in water because of the chemistry of their structure They are soluble in oil Lipids are composed primarily of Carbon and Hydrogen atoms bonded to each other

Lipids Saturated Fat – each carbon is bonded to as many hydrogen atoms as is possible Unsaturated Fat – not every carbon is bonded to all hydrogens as is possible, and therefore, double and triple bonds form between carbon atoms Lipids serve as long term energy storage for cells, and also serve as the primary component of all cells plasma membrane (barrier to outside world)

Lipids