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Chemical basis of molecular interactions
Polar and nonpolar moleculesWater
Universal solvent
O-H bonds are polarizedPartial positive and negative charges
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Chemical basis of molecular interactions
Polar and nonpolar molecules
Hydrocarbons are nonpolar
Properties are conferred by functional groups
A functional groupBehaves as a unit
Confers physical properties, chemical reactivity, & solubility
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Chemical basis of molecular interactions
Noncovalent bondsNot based on electron sharing
Attractive forces – readily broken and reformed
Major classesIonic bonds
Hydrogen bonds
Hydrophobic interactions and van der Waals forces
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Chemical basis of molecular interactions
Classification of Bio-Molecules by functionMacromolecules
Four major categoriesCarbohydrates
Lipids
Proteins
Nucleic Acids
Metabolic intermediates (metabolites)
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Classification of Bio-Molecules
CarbohydratesSimple sugars (monosaccharides)
Small chains (oligosaccharides)
Long chains (polysaccharides)
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Classification of Bio-Molecules
CarbohydratesSimple sugars (monosaccharides)
Linking simple sugars by covalent glycosidic bonds – form :
Small chains (oligosaccharides)
Long chains (polysaccharides)
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CarbohydratesGlycogen
Branched polymer containing only one type of monomer – glucose
Starch – in plants Amylose
Unbranched, helical
Amylopectin
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Lipids
Fats – Fatty AcidsLong, unbranched hydrocarbon chains
Single terminal carboxyl group
Each end has very different structure and properties
Hydrocarbon chain is hydrophobic
Carboxyl end group is hydrophilic
Termed amphipathic
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Lipids
Fats A Fat molecule may have the same FA or mixed FA
High energy reserve
One gram of fat contains over twice the energy of one gram of carbohydrate – lack water.
Stored in specialized cells – adipocytes
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Lipids
Steroids Built around a characteristic four ring hydrocarbon skeleton
Cholesterol
Precursor for steroid hormones
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Lipids
Phospholipids A diacylglycerol structure
Third hydroxyl group on the glycerol is covalently bonded to a phosphate group – then linked to a small polar group (eg. Choline)
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Nucleic AcidsMacromolecules – long strand of monomer nucleotides
Primary function – storage and transmission of genetic information
Also structural and catalytic roles
Two typesDeoxyribonucleic acid – DNA
Ribonucleic acid - RNA
Classification of Bio-Molecules
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Nucleic AcidsRNA
Each nucleotide has three partsA five-carbon sugar – ribose
A nitrogenous base (having N in the ring structure of the molecule)
A phosphate group
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Nucleic AcidsRNA
Each nucleotide has three partsPhosphate linked to the 5’ carbon of ribose
The nitrogenous base is linked to the 1’ carbon of ribose
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Nucleic AcidsRNA
During the assembly of the nucleic acid strand
The OH group on the 3’ carbon of ribose on one nucleotide is linked by an ester bond to the phosphate group of its neighbor
The nucleotides are connected by sugar-phosphate linkages
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Nucleic AcidsRNA
Nitrogenous basesTwo groups
Pyrimidines – smaller – single ring
Purines – larger – two rings
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Nucleic AcidsRNA
Nitrogenous basesTwo groups
Pyrimidines – smaller – single ring
cytosine and uracil
Purines – larger – two rings
adenine and guanine
DNAThymine replaces uracil