FINAL EXAM CHAPTER 4 Protein Flashcards
What do Disulfide bonds cross linked and what is used to form them?
-The polypeptide chain can be cross linked
-Formed by the oxidation of two cysteines
In polypeptides, what end is the beginning and what end is the end?
-Beginning is the Amino terminal end
-End is the Carboxyl terminal end
What are the general properties of a protein ?
-The most abundant substance in most cells except water.
-10-20% by weight
Define Primary structures
-Amino acids linked by peptide bonds to form polypeptide chains
Define secondary structures
Polypeptide chains can fold into regular structures
Define Tertiary structures
Water soluble proteins fold into compact structures
Define Quaternary structure
Multiple polypeptide chains can assemble into a single protein
Which bonds rotations are permitted and why?
-N-C bond and the C-CO bonds are permitted as they are torsion angles that determine the path of the polypeptide chains and not all torsion angles are permitted
What is an alpha helix and what are the properties of it?
-A tightly coiled rodlike structure with the R groups bristling out from the axis of the helix
In an alpha helix, each turn is made of how many amino acids?
3.6 amino acids
What are alpha helix and beta sheets stabilized by?
Hydrogen bonds
What are beta sheets formed by and what does it look like?
-Formed by adjacent beta strands
-it may be parallel, antiparallel or mixed, it can also be almost flat or adopt a twisted conformation
What is a Keratin composed of?
Two right handed alpha helices intertwined to form a left handed superhelix called a coiled coil.
What is a Collagen composed of?
Three intertwined helical polypeptide chains that form a superhelical cable and these aren’t alpha helices
What stabilizes a tertiary structure?
weak vdW bonds
