Chapter 2- Proteins Part 1 Flashcards
Proteins have many __________ roles
biological
What are proteins roles?
enzymes, structure, transport and binding
proteins are built from _____ amino acids which are the amino acids ____________.
the 20 common or standard, coded by genes into protein synthesis
Amino Acid structure is
Amine (NH3) + Carboxylic Acid (COO-) + H + R group
What type of isomer makes proteins and amino acids?
L isomer
What are the 4 classifications for the 20 standard amino acids?
non polar, polar, basic and acidic
Draw alanine.
CH3 sticking North, nonpolar, not strongly hydrophobic
Describe Glycine.
H sticking North, It is achiral, non polar, not strongly hydrophobic
Which amino acids are non polar?
Valine, Leucine, Isoleucine, Methionine (has a sulfur)
Which amino acid reacts with its backbone?
Proline (its backbone is a CH2 plus CH2 plus CH2 connected to the N+H2)
Which are the aromatic amino acid?
phenylalanine, tyrosine (non polar, has hydroxides) , tryptophan (biggest amino acid)
What are the 3 hydroxide amino acids?
Tyrosine, Serine, Threonine
Which amino acids are polar non ionizable Amino Acids?
Serine, Threonine, Asparagine, Glutamine
What is special about glutamine?
That it has a polar amide (a double bonded O to a C attached to a N) in the side chain
What is the most chemically reactive amino acid? And what does it look like?
Cysteine (amino acid structure plus CH2 attached to a S attached to a H)
Which amino acid has a 5 membered ring?
Hisitidine
Which are the acidic amino acids?
Aspartate and Glutamate
What is a characteristic of all acid base reactions?
Protonation
Low pH= net + or - charge?
+
High pH= net + or - charge?
-
Which pKa are approximately 3-4?
- terminal alpha carboxyl group
- aspartic acid
- glutamic acid
Which pKa are approximately 6-8?
Histidine (closer to biological pH which is 7.5)
Which pKa is approximately “fairly” high above 7?
terminal amino group
Which pKa is approximately “high” above 7?
- lysine
- arginine
What is the most reactive amino acid and why?
Cysteine because it can form a disulfide bonded cystine (two cysteines attach at the cystine). It has a thiol in its side chain
Amino acids can be held together by what?
amide bonds called peptide bonds
The peptide bond is most famous for…
breaking down pepsin (peptobismo, pepsi)
Biological polypeptides are divided into what?
peptides and proteins (depending on length)
Biological polypeptides are classified how?
Peptides (small, 30ish or smaller monomers long, short enough where it can’t have 3D structure)
Proteins (large, 30ish or longer monomers long, long enough to have 3D structure)
Protein structure is the basis of what?
protein function and its divided into levels because of its complexity.
Structure determines what?
function (just like a protein that bind to DNA can determine function because of its specificity)
A protein found in mammalian milk needs to have what in order to bind to what?
Needs to have high affinity and high specificity so that iron can bind
What are the levels of protein structure?
Primary structure
Secondary structure
Tertiary structure
Quaternary structure