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Molecules of Life. Polymers Are Built of Monomers. Organic molecules are formed by living organisms have a carbon-based core the core has attached groups of atoms called functional groups the functional groups confer specific chemical properties on the organic molecules.
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Polymers Are Built of Monomers • Organic molecules are formed by living organisms • have a carbon-based core • the core has attached groups of atoms called functional groups • the functional groups confer specific chemical properties on the organic molecules
Polymers Are Built of Monomers • The building materials of the body are known as macromolecules because they can be very large • There are four types of macromolecules: • Proteins • Nucleic acids • Carbohydrates • Lipids • Large macromolecules are actually assembled from many similar small components, called monomers • the assembled chain of monomers is known as a polymer
Macromolecule Formation • There are 4 major categories of organic molecules in living organisms: • Carbohydrates • Lipids • Protein • Nucleic acids
Macromolecules • A macromolecule is built upon repeating subunits called polymers. • Macromolecules are large and complex. • An organic molecule is based on long chains of carbon with functional groups on the ends that give the molecule its unique chemical properties.
Macromolecules • All four macromolecules consist of a covalent bond between two subunits..a hydroxyl group is removed from one end and a hydrogen group from the other end. • This process is called dehydration. • Dehydration requires the action of an enzyme to facilitate chemical binding. • Adding of water to the polymer too break them into subunits is called hydrolysis.
Carbohydrates • Carbohydrates are energy sources and are made of polymers of simple carbohydrates. • Simple carbohydrates include monosaccharides and disaccharides. • Complex carbohydrates are polysaccharides formed from glucose. • Component of plant cell walls, outer skeletons of insects. • Ex.: chitin, cellulose, glycogen, starch.
Carbohydrates • Carbohydrates are monomers that make up the structural framework of cells and play a critical role in energy storage • a carbohydrate is any molecule that contains the elements C, H, and O in a 1:2:1 ratio • the sizes of carbohydrates varies • simple carbohydrates – consist of one or two monomers • complex carbohydrates – are long polymers
Carbohydrates • Simple carbohydrates are small • monosaccharides consist of only one monomer subunit • an example is the sugar glucose (C6H12O6) • disaccharides consist of two monosaccharides • an example is the sugar sucrose, which is formed by joining together two monosaccharides, glucose and fructose
Carbohydrates • Complex carbohydrates are long polymer chains • because they contain many C-H bonds, these carbohydrates are good for storing energy • these bond types are the ones most often broken by organisms to obtain energy • the long chains are called polysaccharides
Carbohydrates • Plants and animals store energy in polysaccharide chains formed from glucose • plants form starch • animals form glycogen • Some polysaccharides are structural and resistant to digestion by enzymes • plants form cellulose cell walls • some animals form chitin for exoskeletons
Lipids • Fats and all other biological materials that are not soluble in water, but are soluble in oil are lipids. • Used for long term energy storage. • Fats: • Triglycerols are made of glycerol and three fatty acids. • Fatty acids may be saturated or unsaturated with hydrogen along the carbon chain.
Lipids • Fats are used for: • Energy storage; • Components of cell membranes (phospholipids); • Message transmission (steroids); • Pigmentation.
Lipids • Fatty acids have different chemical properties due to the number of hydrogens that are attached to the non-carboxyl carbons • if the maximum number of hydrogens are attached, then the fat is said to be saturated • if there are fewer than the maximum attached, then the fat is said to be unsaturated
Proteins • Proteins may serve as enzymes, play a structural role, and act as chemical messengers. • They are polypeptides made up of amino acids joined by peptide bonds. • Act as catalysts.
Proteins • Protein structure: • The sequence of amino acids within the protein is called the primary structure. • Any folding of the primary chain structure is called the secondary structure. • Globular shapes are the tertiary structure of a protein. • When more than one polypeptide chain composes the protein, it has quaternary structure. • The shape of a protein can be denatured (poor function results).
Proteins • There are four general levels of protein structure • Primary • Secondary • Tertiary • Quaternary
Proteins • Primary structure – the sequence of amino acids in the polypeptide chain • This determines all other levels of protein structure Figure 4.7 Levels of protein structure: primary structure
Proteins • Secondary structure forms because regions of the polypeptide that are non-polar are forced together; hydrogen bonds can form between different parts of the chain • The folded structure may resemble coils, helices, or sheets Figure 4.7 Levels of protein structure: secondary structure
Proteins • Tertiary structure – the final 3-D shape of the protein • The final twists and folds that lead to this shape are the result of polarity differences in regions of the polypeptide Insert Figure 4.7 from TLW 6e
Proteins • Quaternary structure – the spatial arrangement of proteins comprised of more than one polypeptide chain Figure 4.7 Levels of protein structure: quaternary structure
Protein • The shape of a protein affects its function • changes to the environment of the protein may cause it to unfold or denature • increased temperature or lower pH affects hydrogen bonding, which is involved in the folding process • a denatured protein is inactive
Nucleic Acids • Nucleic acids (polynucleotides) store information for cells. • DNA (Deoxyribonucleic acid) exists as a double helix of polynucleotides, using base pairing within the helix. • Base pairing dependent upon hydrogen bonding. • DNA encodes genetic materials and ribonucleic acid (RNA) is involved in protein synthesis.
The Double Helix • The reason for DNA to assume its double helix is because only two base pairs are possible: Adenine-Thymine and Guanine-Cytosine. • The advantage of the double helix is that it contains two copies of the information—one the mirror image of the other.
