chemistry
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Chemistry
Macromolecules
Macromolecules
• Small molecules linked together to create large molecules
– Have shape created by hydrogen bonding, sulfhydryl bonding, polarity, etc.
• FORM FITS FUNCTION
– Ex. Proteins do ‘everything’
Protein
Stanley Miller Linus Pauling
Carbon bonds 4 times in multiple ways
Creates great variety
Hydrocarbons
ISOMER
Isomers = molecules
with the same formula but
different structural
formulae; not isotope
AMP
ATP
GTP
Differences in functional groups
What is a functional group?
Ethane
Ethanol
Functional group
Functional groups -Create the necessary variety of shapes of macromolecules for life to exist
Dehydration synthesis =
enzymatically controlled
formation of large molecules by
removal of water
Macromolecules
• Monomers + monomers + monomers = polymers
• Produced by DEHYDRATION SYNTHESIS
• Hydrolysis – breakdown of macromolecules by the addition of water
• Enzymes
Macromolecules• What do you need to know for each
macromolecule important to life:
– Structure
– Monomers
– Function in organisms
Macromolecules
• Carbohydrates
• Lipids
• Proteins
• Nucleic acids
Carbohydrates
• Carbon + water (hydrate)
• Basic formula: CH2O(n)
• Monomers = monosaccharide (‘one sugar’)
• End in ‘ose’
Monosaccharides
• Glucose C6H12O6
• Many monomers form rings in aqueous solutions to become more stable
• Monomers may be functional:
– Glucose is primary source of energy for organisms
Carbohydrates• Monomer + monomer = dimer• Monosaccharide + monosaccharide = disaccharide • Glucose + glucose = maltose• Glucose + fructose = sucrose• Glucose + galactose = lactose
Polysaccharides
• Polymers of monosaccharides
• Type of monosaccharide and arrangement creates variation in polysaccharides
• Starch (Amylose, amylopectin) = plants
• Glycogen = energy storage for animals
• Cellulose = plant cell walls
• Chitin = exoskeleton of arthropods, some fungi
Carbohydrates: Function
• Energy; stored energy (which?)
• Structure – (which?)
• Cell-to-cell communication, identification (glycoproteins, glycolipids)
– Antigens /antibodies
Lipids • InsolubleInsoluble in water; (long, nonpolar
hydrocarbon chains) • Basic formula: C50H70O6
• Three types:– Fats, oils, waxes– Phospholipids – Steroids
Lipids: Fats
• Macromolecules of glycerol + 3 fatty acids
• Glycerol = glyc = ‘sugar’ C3H8O3
• Fatty acids = hydrocarbon chain (16-18 carbons)– Hydrocarbon chain is hydrophobic
Lipids: Fats
• Fats = triglycerides (3 fatty acids)
• Structure of the fatty acid chains creates variety in types of fats
– Saturated – full of hydrogen atoms; no double bonds
– Unsaturated – not full; double bond(s)
Types of Fats
• Saturated
• No double bonds• Saturated• Solids @ (200)• Animal fats• Bacon grease, lard,
butter
• Unsaturated • Double bond(s)• Unsaturated• Liquids @ (200)• Plant fats (oil)• Corn, peanut, olive
oils
Link between an acid and a sugar
Triglycerides
• Important to diet
• Limit amount of saturated fats
• Hydrocarbon chains are high in energy
• More difficult to breakdown
• Link to triglycerides and arteriosclerosis
Lipids: Phospholipids
• Glycerol + 2 fatty acids • 3rd position on the glycerol is taken by a phosphate
group (PO4)
Phospholipids
• Major component of cell membrane
• ‘head’ end (glycerol) is polar (term?)• Hydrophilic = “water loving”• ‘tail’ end is non-polar (term?)• Hydrophobic = “water fearing”
Phospholipids• Phospholipids in water form a micelle
• First prokaryotes evolved when phospholipids formed micelles in water (?)
• Abiogenesis
Steroids
• 4 fused carbon rings + functional group
• Insoluble in water
• Ex. Cholesterol
– Between fatty acids tails of phospholipids
– Help to moderate the effects of extreme temperatures
Steroids
• Precursors of sex hormones
• Too much causes atherosclerosis (?)
Importance
• Energy (?)• Padding (?)• Insulation (?)• Structure (?)• Hormones (?)
Proteins
• Many shapes = many functions
• ‘first place’
• Polymers of AMINO ACIDS
• Linked by PEPTIDE BONDS
• POLYPEPTIDES
• Proteins = folded, shaped polypeptides
Proteins: Amino Acids
• 2 carbon skeleton
– Amino group
– Carboxyl group
– H atom
• Side group (R group)
Proteins: Amino Acids
• R group determines properties of the aa– Some are polar, some are nonpolar– Polar may be acidic or alkaline
• 20 different amino acids• Essential = body cannot produce on its own
Proteins
• Peptide bonds are the result of dehydration synthesis
• Amino group reacts with carboxyl group of adjacent amino acid
• Polypeptide - string of polypeptide bonds
Proteins• Function depends upon shape
• Conformation – 3d shape caused by H-bonds
– Fold and twist the amino acids
• Globular
– Insulin, enzymes
• Fibrous = ‘stringy’
– Silk, muscle
Proteins
• Four levels of protein structure that give a protein its unique shape:
– Primary
– Secondary
– Tertiary
– Quaternary
Proteins: Primary Structure
• Sequence of amino acids
– Determined by genetic code
– ‘goof’ in sequence can have harmful or lethal effects
Secondary Structure
• Folds or twists created by H-bonding in the carbon backbone; NOT the R group
• 2 types: both may be in a protein – Alpha - helix – Beta - pleated sheet
Tertiary Structure• Irregular contortions caused
by bonding of R groups:– Ionic, hydrogen, disulfide
bridges (covalent)• Hydrophobic interaction -
nonpolar portions tend to line up in core of the protein
Quaternary Structure
• Multiple polypeptides in one giant protein
– Hemoglobin (heme + globin)
Protein Shape
• Primary – (?)• Secondary – (?)• Tertiary – (?) • Quaternary – (?)
Denaturation
• Alteration of conformational shape
• Caused by:
– pH, salinity, organic solvents (alcohols, carbon tetrachloride, acetone, etc.), heat, inorganic chemicals that dissolve bonds (HCl)
• Some change shape to function
– Receptor, contractile
Denatured proteins are the cause of….
Polypeptide to Protein
• Polypeptides are NOT proteins– Need to be folded into conformational
shape• Chaperonins = proteins that aid in the
folding into conformational shape• Knowledge of protein folding helps to
manufacture proteins
Determining the Structure of Molecules
• X-ray diffraction
• Electron density map
• Computer
Rosalind Franklin: X-ray diffraction of
DNA
Nucleic Acids
• DNA, RNA
• Polymers of nucleotides
• Nucleotide:
– Simple sugar (ribose or deoxyribose)
– Nitrogenous base
– Phosphate group (PO3)
4 nitrogenous bases: Purines Pyrimidines
Nucleic Acids
• Nitrogenous bases are complimentary
• A-T
• C-G
• Hydrogen bonds
• Sugar-phosphate backbone
H bonding
Relationship between
nucleic acids and proteins
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