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•Macromolecules - larger molecules made from smaller ones.
• 4 major classes of macromolecules: carbohydrates, lipids, proteins, and nucleic acids.
• 3 of these are polymers because they are made from individual building blocks called monomers.
http://www.diabetes.org.nz/pics/carbohydrate_foods.jpg
•Monomers - joined together through condensation or dehydration reaction (form macromolecules)
• Requires energy; uses covalent bonds (links together monomers)
• Water produced.
Water produced as by-product
•Hydrolysis breaks polymers into monomers.
• Water added to polymer; breaks bonds, creates monomers (i.e. digestive process in animals)
Carbohydrates• 1Carbohydrates - sugars
(monomers) and polymers.
• AMonosaccharides - simple sugars.
• BDisaccharides - double sugars (monosaccharides linked together)
• CPolysaccharides - polymers of monosaccharides.
• Sugars named with –ose.
• Monosaccharides needed for cellular work.
• Help to synthesize other macromolecules.
• Maltose - 2 glucose molecules.• Sucrose - 1 glucose, 1 fructose.
•Polysaccharides - energy storage.
• Starch - energy storage polysaccharide for plants.
• Cellulose – polysaccharide; plant cell walls.
• Animals store energy as glycogen.
• Chitin - polysaccharide - makes up exoskeleton of arthropods (like crustaceans and our sowbugs!).
Chitin is used in surgery
Lipids•Lipids - no polymers (exception)• Lipids nonpolar (no affinity for
water)• Fat made from glycerol and fatty
acids.
•Saturated fatty acid - No carbon-carbon double bonds in carbohydrate chain. (hydrogen at every possible position)
• Form bad fats - solid at room temperature (butter, lard)
No double-double bonds
•unsaturated fatty acid - 1+ carbon-carbon double bonds.
• Formed by removal of hydrogen atoms from carbon skeleton.
• Form good fats - liquid at room temperature (oils)
• Purpose of fat - energy storage. • Gram of fat stores 2X as much
energy as gram of polysaccharide.
• Fat also cushions vital organs.• Layer of fat can also function as
insulation.
http://www.healthline.com/blogs/diet_nutrition/uploaded_images/fat-cat-712938.jpg
• MOST IMPORTANT LIPID IN BIOLOGY = Phospholipid
• Phospholipids have 2 fatty acids attached to glycerol.
• Fatty acid tails are hydrophobic, phosphate group and attachments form hydrophilic head.
• When phospholipids added to water, self-assemble with hydrophobic tails pointing toward center, hydrophilic heads on outside.
• Phospholipids in cell form bilayer; major component of cell membrane.
Hydrophilic
Hydrophobic
Other Lipids
•Steroids - lipids with carbon skeleton consisting of 4 fused carbon rings.
• Cholesterol - component in animal cell membranes and hormones.
Cholesterol
Proteins
•Proteins - support, storage, transport, defenses, and enzymes.
• Made in ribosomes in cell.• Proteins - amino acids linked
together to form polymer.• 20 different amino acids that can
be linked together to form thousands of different proteins.
http://images.foodnetwork.com/webfood/images/gethealthy/nutritionalallstars/LeanProteins_header.jpg
• Amino acids link - polypeptides - combine to form proteins.
• Amino acids made of hydrogen atom, carboxyl group, amino group, variable R group (or side chain).
• R group makes amino acids different from one another.
• Shape of protein determines function.
• Shapes - 3 dimensional - determined by sequence of amino acids.
•Primary structure of protein - linear sequence of amino acids determined by genetics.
•Secondary structure - two shapes are usually formed: alpha coils or beta sheets.
•Tertiary structure determined by interactions among R groups.
•Quarternary structure - joining of 2+ polypeptide subunits.
• Collagen and hemoglobin examples.
• Protein’s shape can change due to environment.
• pH, temperature, or salinity (salt concentrations) change - protein can denature (starts to fall apart)
• Some proteins can return to functional shape after denaturation, others cannot.
Nucleic acids
• Amino acid sequence of polypeptide programmed by a gene.
• 2 types of nucleic acids: ribonucleic acid (RNA) and deoxyribonucleic acid (DNA).
http://www.uic.edu/classes/bios/bios100/lecturesf04am/nucleotides.jpg
• DNA gives information so RNA can create proteins.
• Flow of genetic information - DNA -> RNA -> protein.
• Protein synthesis occurs in ribosomes.
• Monomers of nucleic acids - nucleotides.
• Nucleotides made up of 3 parts: nitrogen base, five-carbon sugar, and phosphate group.
• Nitrogen bases, rings of carbon and nitrogen, come in 2 types: purines and pyrimidines.
•Pyrimidines - cytosine (C), thymine (T), and uracil (U in RNA only).
•Purines - adenine (A) and guanine (G).
• Pyrimidines - single six-membered ring; purines - five-membered ring.
http://library.med.utah.edu/NetBiochem/pupyr/pupy3.gif
• In RNA - sugar is ribose; DNA - sugar is deoxyribose.
• Difference between sugars is lack of oxygen atom in deoxyribose.
http://members.aol.com/logan20/ribose.gif
• RNA single-stranded - linear shape.
• DNA forms double helix.• Sugar and phosphate forms
backbone of double helix while nitrogen bases form connection between backbones.
• Adenine (A) always pairs with thymine (T) guanine (G) with cytosine (C).
• Due to six and five membered rings – shapes are compatible.
• Two strands are complementary.
http://www.emunix.emich.edu/~rwinning/genetics/pics/dna2.gif
• DNA used to show evolutionary similarities between species.
• Two species that appear to be closely-related based on fossil and molecular evidence also more similar in DNA and protein sequences than more distantly related species.
