Flashcards in Proteins Deck (43)
4 parts of an amino acid
*all are bonded to common carbon core
1. H - hydrogen atom
2. NH2 - amino functional group
3. COOH - carboxyl functional group
4. a distinctive "R-group"
What happens to amino acids in water?
They ionize due to the pH of 7
What acts as a base in an amino acid?
Amino group (NH2)
What acts as an acid in an amino acid?
Carboxyl group (COOH)
The two highly electronegative oxygens pull the hydrogen away
What makes the amino acids unique?
What happens if an R-group just contains carbon and hydrogen?
They will not participate in many chemical reactions
Polar and electrically charged
Nonpolar R-groups or highly electronegative atoms capable of forming hydrogen bonds with water
Does the R-group have a negative charge?
If yes, it is acidic and will lose a proton
Does the R-group have a positive charge?
If yes, it is basic and will pick up a proton
If the R-group is uncharged, does it have an oxygen atom?
If yes, then the highly electronegative oxygen atom will form a polar covalent bond, thus making it uncharged
also called condensation reactions
newly formed bond results in the loss of water
What type of bond is a peptide bond?
What do peptide bonds occur between?
carboxyl group of one amino acid and the amino group of another amino acid
2 hydrogens from (NH2) react with one oxygen from (COOH) to form the peptide bond
Are peptide bonds stable?
Yes due to the degree of electron sharing
amino acids that are linked together in a chain
R-group orientation in residue
Side chains (R-group) stick out which makes it possible for them to react with eachother and to react with water
What is the directionality of the residue?
N-terminus (amino group) to C-terminus (carboxyl group)
a polymer with fewer than 50 amino acids
a polymer with more than 50 amino acids
refers to the distinct amino acid sequence
R-groups affect chemical reactivity and solubility
distinctively shaped sections that are stabilized by hydrogen bonding that occurs between the oxygen on the C=O group of one amino acid residue and the N-H groups on another
the polypeptide's backbone is coiled
segments of the peptide chain fold in the same plane
rarely found in a-helixes
form using a variety of bonds and interactions between R-groups or between R-groups and the backbone
Types of interactions used for tertiary structures
1. Hydrogen bonding
2. Hydrophobic interactions
3. van de Waals interactions
4. Covalent bonding
5. Ionic bonding
form between polar side chains and opposite partial charges either in the peptide backbone or other R-groups
water molecules force the hydrophobic nonpolar side chains to merge into globular masses