36 terms

Amino Acids, Sugars, nucleotides and Lipids

Chapter 3:
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Proteins
Monomer: amino acid
polymer: protein/polypeptide
20 possible amino acids, linear polymers, complex sequences possible
Carbohydrates
Monomer: simple sugars monosaccharides
polymer: polysaccharides
numerous sugars with modification. polymer can be branched
Nucleic Acid
Monomer: nucleotide
Polymer:polyribonucleic acid, polydeoxyribonucleic acid. 4 possible nucleotides
Functional Groups
groups of atoms with specific chemical properties and consistent behavior
Hydroxyl
Alcohols ex: ethanol. Polar. Hydrogen bonds with water to help dissolve molecules. Enables linkages to other molecules by dehydration.
Aldehyde
ex: Acetaldehyde. Important in building molecules and in energy-releasing reactions. C=O group is very reactive.
Keto
Ketones ex: Acetone C=O group is important in carbohydrates and energy reactions
Carboxyl
ionizable. Carboxylic Acid ex: Acetic Acid. Enters into dehydration synthesis by giving up OH- Ionizes in living tissue to form COO- and H+
Amino
Amines, ex: Methylamine. Accepts H+in living tissues to form NH3 and enters dehydration synthesis by giving up H+
Isomers
molecules with the same chemical formula but atoms are arranged differently
structural isomers
differ in how their atoms are joined together
Optical Isomers
carbon atom has four different atoms or groups of atoms attached to it.
Functional group of Amino Acids
Carboxyl and Amino. function as both acid and a base. Chiral/assymetrical
D-amino Acids
amino acid in its right isomeric form
L-Amino acids
amino acid in its left isomeric form and exists in organisms
Charged
Amino acids can be grouped based on side chains
Hydrophilic amino acids attract ions of opposite charges
+: R, H, K, amines (Arginine, Histidine, lysine)
-:D, E, carboxyls (Aspartic Acid, Glutamic Acid)
polar uncharged
hydrophilic amino acid with polar but uncharged side chains from hydrogen bonds
S, T, Y (OH) (Serine, theronine, Tyrosine
N,Q amide Asparagine, Glutamine)
Non-Polar
FAMILY VW hydrophobic amino acids (Phenelalanine, Alanine, Methionine, Isoleucine, Leucine, Valine, Tryptophan
Special cases:
C, G, P Not Chiral hydrophilic (cysteine, glycine, plorine)
Cysteine
Terminal SH group can react with another same side chain to form a disulfide bridge important in protein folding.
Peptide Linkages
Amino Acids bond together covalently in a condensation reaction. Peptide bond is inflexible, no rotation is possible
primary structure
of a protein is the sequence of amino acids 20^100 possible proteins. 1X10^130 sequences
Carbohydrates
Have the general formula CH2O Source of Stored Energy, Transport stored Energy, Carbon Skeletons for many other molecules
Disaccharides
Two simple sugars linked by a covalent bond
Oligosaccharides
three to 20 monosaccharides
Polysaccharides
hundred or thousands of monosaccharides. starch, glycogen, cellulose. chains of sugars
glucose
cells use this monosaccharide as an energy source or currency. Exists as a straight chain or ring form. Ring is more stable.
glycosidic linkages
Monosaccharides bind together in condensation reactions.
RNA
ribose, hydroxyl
DNA
Deoxyribose, missing an oxygen. proton, phosphate, sugar, base
Lipids
non-polar hydrocarbon tails. Fatty acids joined to glycerol. Van der Waals force hold them together and creation of hydrogen shell is disfavored.
Noncovalent assemblies of lipids
Bilayers, Micelles, membranes. driven by hydrophobic interactions
Ester Linkages
Lipids are composed of fatty acids joined to glycerol and are amphipathic and have a carboxyl group.
Saturated Fatty Acids
no double bonds between carbons, it is saturated with H atoms. ex: animal fats, packed together tightly; solid at room temperature
Unsaturated Fatty Acids
some double bonds in carbon chains.
mono-one double bond
poly- more than one
ex: plant oils, not as closely packed, liquid at room temperature
Phospholipids
fatty acids bound to glycerol; a phosphate group replaces one fatty acid
hydrophilic head
tails are fatty acid chains-hydrophobic