Chapter 3 - Protein, Carbohydrates and Lipids Flashcards
Monomer
A molecule that can be covalently bonded to other identical molecules to form a polymer
Isomers
Molecules that have the same chemical formula, the same kinds and numbers of atoms, but with the atoms arranged differently
Structural Isomers
Isomers that differ in how their atoms are joined together
Cis-trans Isomers (geometric)
Same molecular formula but must contain a C=C (carbon carbon double bond)
Optical Isomers (stereoisomers or enantiomers)
Two 3D molecules that are mirror images of each other; not superimposable (placed on top of each other); one isomer typically is biologically active and the other isomer is inactive
Chiral Carbon
When a carbon atom has 4 different atoms or groups of atoms attached to it
Condensation (Dehydration) Reactions
Result in the formation of covalent bonds between the same type of monomers (ie. 2 amino acids, 2 nucleotides, etc); an H2O is removed
Hydrolysis
Result in the breakdown of polymers into their component monomers to release energy
Protein
Polymers made up of 20 amino acids in different proportions and sequences; most prevalent macromolecule
Zwitterion
A molecule or ion having separate positively and negatively charged groups
Amino Acids
Building blocks of protein; contains an amino group, a carboxyl group, a hydrogen and a R group (side chain) all attached to a carbon atom
Polypeptide chain
Single, unbranched chain of amino acids
Amino acids are in what 2 isomeric forms?
Amino acids are optical isomers with with a right side, D-amino acid, and a left side, L-amino acid; L-amino acids are found in organisms
Disulfide bridge
The terminal –SH group of cysteine can react with another cysteine side chain to form a disulfide bridge or disulfide bond (–S–S–); this creates protein folding in the tertiary structure
Primary structure of protein
Sequence of amino acids that determines the secondary and tertiary structure–how the protein is folded
Secondary structure of protein
Amino sequences creates two types of secondary structures: alpha helix and beta pleated sheet; these structures are due to the interactions of the backbone or polypeptide chain(s)
Alpha helix
Right handed coil (clockwise) resulting from hydrogen bonding between N–H groups on one amino acid and C=O groups on another
Beta pleated sheet
2 or more polypeptide chains that are aligned; hydrogen bonds form between the chains
Functional groups
Groups of atoms with specific chemical properties and consistent behavior; hydroxyl, aldehyde, keto, carboxyl, amino, phosphate, sulfhydryl functional groups
Tertiary structure
Bending and folding results in a macromolecule with a specific 3-D shape; determined by interactions between R-groups/side chains
Denaturation
Heating a protein will break down the secondary and tertiary structures causing protein denaturation
Renaturation
When cooled, a denatured protein can sometimes return to its normal tertiary structure
Degradation
The breakage of peptide bonds in the primary structure of the protein; irreversible
Proline side chain
Forms a ring, which limits its hydrogen bonding ability and the ability to rotate about the alpha carbon; often found where a protein bends or loops in the secondary structure
Quaternary structure
Functional proteins contain 2 more polypeptide chains or subunits and results from the ways the subunits interact–hydrophobic interactions, van der Waals forces, ionic attractions and hydrogen bonds
Conditions that alter secondary and tertiary structure
Increased temperature, pH and salt concentrations
Chaperone
A protein that surrounds a denatured protein and allows it to refold or surrounds a newly formed unfolded protein and allows it fold properly
When do proteins change shape?
Interaction with other molecules; covalent modification–addition of a chemical group to an amino acid
Carbohydrate
A macromolecule that is a source of stored energy and used to transport stored energy; can be a straight chain or ring (ring is stronger)
Monosaccharide
Carbohydrate monomer that has a 1-ring structure; simple sugars; ie. glucose
Disaccharide
2 simple sugars linked by covalent bonds
Oligosaccharides
Carbohydrates made up of 3-20 monosaccharides linked by covalent bonds; often covalently bonded to proteins and lipids on cell surfaces
Polysaccharide
Carbohydrates made up of hundreds to thousands of monosaccharides; ie. starch, glycogen, cellulose
Glucose
Monosaccharide that all cells use an energy source; ring chain form is more common and stable; alpha-glucose contains an attached –H above Carbon-1; beta-glucose contains an attached –OH above Carbon-1
Glycosidic linkages
Monosaccharides bind together in condensation reactions; glycosidic bonds can be alpha–both monosaccharides connected downward, or beta–both monosaccharides connected cross diagonally
Starch
Polysaccharide in a helix shape that is the storage of glucose in plants; alpha linkages hold monomers together
Glycogen
Polysaccharide in a branch shape that is the storage of glucose in animals; alpha linkages hold monomers together
Cellulose
Polysaccharide in a linear shape that very stable and good for structural components; beta linkages hold monomers together
Chemically modified carbohydrate
Carbohydrate modified by oxidation-reduction reactions by the additional attachment of functional groups–phosphate, groups, amino groups, N-acetal groups (chitin)
Lipids
Nonpolar hydrocarbons that are insoluble in H2O; not covalently bonded
Triglyceride
Fats and oils that contain 3 fatty acid chains (hydrophobic) and 1 glycerol molecule (hydrophilic)
Ester linkage
A condensation/dehydration reaction that covalent bond between the carboxyl group of fatty acids and a hydroxyl group of glycerol
Saturated fatty acid
The bonds between C and the hydrocarbon chain are single bonds–the fatty acids are saturated with H atoms; molecules are packed tightly; Animals fats–butter are packed tightly and solid at room temperature
Unsaturated fatty acids
The fatty acid hydrocarbon chain contains 1 or more double bond–creates kinks; Plant oils are liquid at room temperature and have unsaturated tails which prevents them being packed tightly
Amphipathic
Fatty acids have opposing chemical properties; The hydrophobic tail (nonpolar hydrocarbon chain) and hydrophilic head (carboxyl group) have opposing reactions to water
Phospholipid
A glycerol bound to1 phosphate group (hydrophic head) and 2 fatty acids (hydrophobic tails); amphipathic
Phospholipid bilayer
2 layers of phospholipids that line up the hydrophobic tails together facing inward and the phosphate heads facing outward; ie. biological membranes
Steroids
A type of lipid that is structured with multiple rings that share carbons; three 6-membered rings attached to one 5-member ring; ***memorize the structure; functions as hormones
Cholesterol
Type of lipid/steroid that is an important constituent of cell membranes
