Chapter 2.4 proteins Flashcards
Peptide
two or more amino acids joined by peptide bonds
How are peptide bonds formed?
Which functional groups connect peptides together?
Dehydration synthesis
Amino group of one amino acid to carboxyl group of the next
3 Characteristics of amino acids
-Central carbon atom with an amino group, carboxyl group, hydrogen, and R group
-All amino acids identical except for radical group
-Often amphipathic
Oligopeptide
Chains of amino acids fewer than 10 or 15
Polypeptides
10 or 15 or more chains of amino acids
How many chains Of amino acids does a polypeptide need to be a protein?
50 or more
Primary structure Of a protein And it’s associated bond
Proteins sequence of amino acids; peptide bonds
Secondary structures and Associated bond
Alpha helix or beta sheets held together by hydrogen bonds
Tertiary structure and associated bonds
further bending and folding of proteins into various globular and fibrous shapes.
Van der waals forces and hydrophilic/phobic interactions
Globular proteins
Look like a watered ball of yarn;
-Embedded in cell membranes
-proteins that must move freely like Enzymes and antibodies
Fibrous proteins
Slender filaments such as myosin, keratin, and collagen; provide strength to skin hair and tendons
Disulfide bridges
-In amino acid cysteine
-Formed by covalent bonds
-Holds tertiary structures (separate polypeptide chains) together.
Quaternary structure and associated bonds
-two or more polypeptide chains
-ionic bonds and hydrophilic/hydrophobic interactions
-non-amino moiety: prosthetic group
Ex: hemoglobin
Denaturation
Conformation change that breaks hydrogen bonds; lose structure=lose function
Ex: cook egg white 
Conjugated protein has what bonded to it and how bonded?
Has a prosthetic group; covalently bonded
Ex: glycoproteins: the carbohydrate moiety is a prosthetic group
6 Protein functions:
- Structure
- Communication
3. Membrane transport - Catalysis
- Movement/ adhesion
-  Recognition
Examples of protein structures
Keratin for hair, skin, nails
Collagen for deep layers of skin, bones, cartilage, teeth
Protein recognition and protection
-Antibodies and other proteins attack and Neutralize invading organisms. 
-also clotting proteins
What are enzymes
Proteins that function as biological catalysts
Substrate
The substance the enzyme acts upon
(Adds the suffix -ase
Ex: amylase amyl=starch)
Activation energy
The energy needed to get the reaction started; Enzymes lower activation energy needed
Ex: Burning paper: the match supplies activation energy
Conformation change is important to what?
enzyme function, muscle contraction, and the opening and closing of pores in cell membranes
Enzymes lower the ______ of a reaction 
Activation energy
Enzyme structure and action order of events:
- substrate approach activation site
- Enzyme – substrate complex (Enzyme – substrate specificity)
-  Bond broken or formed; enzyme releases product(s)
Cofactors of enzymes
non-protein INORGANIC partner
Coenzymes
Organic cofactors
Acts as a shuttle that picks up electrons from one metabolic pathway and delivers them to another
Metabolic pathway
A chain of reactions with each step usually catalyzed by a different enzyme
When a macromolecule is conjugated, it is
Covalently bonded to another macromolecule
Conformation
3 dimensional shape
Function of a protein is derived from its what?
Structure
