Essay Ch1 Protein Flashcards
Chemical composition
Proteins are made up of polypeptides, and polypeptides are the polymers of amino acids. The amino acid is composed of the amino functional group, the carboxyl functional group, a hydrogen atom, and a side chain.
Thesis
It consists of a chemical composition, has four different structural levels, and has two nucleotides that aid in it’s synthesis. The end result is proteins ability to transport molecules and aid in membrane structures.
Side chain
The side chain differentiates each of the twenty amino acids, making each one unique. To form a polypeptide amino acids must undergo dehydration synthesis, losing a water molecule, to form a peptide bond.
Combining of amino acids
Many amino acids combine to form a polypeptide, and polypeptides conform to create a protein. The arrangements of polypeptides also determine the structure of the protein.
Primary
The first being the primary structure, which is a sequence of amino acids determined by the genes in DNA. This sequence is a long linear chain.
Secondary
The repeated folding of this peptide chain creates the secondary structure. This folding is stabilized by hydrogen bonds and can either form the alpha helix or the beta pleated sheet structures.
Tertiary
Next, is the tertiary structure, which is globular structures with irregular contortions. This overall shape results from interactions between side chains and various amino acids. The shape is stabilized by hydrogen bonds, ionic bonds, hydrophobic interactions, and disulfide bridges.
Quaternary
The fourth structure which consists of polypeptides, three or more tertiary structures, is the quaternary. Examples containing this structure are hemoglobin and collagen.
Protein synthesis
When it comes to protein synthesis, DNA and RNA are the two nucleotides responsible for the information regarding the construction of the proteins.
DNA
DNA directs the RNA synthesis and controls the protein synthesis. Each gene along a DNA molecule directs synthesis of messenger RNA.
RNA
Messenger RNA helps direct the production of a polypeptide, which as stated, folds into all or part of a protein. It is the messenger RNA that conveys the genetic instructions for building proteins, provided by the DNA, from the nucleus to the ribosomes - where the actual protein synthesis occurs.
Roles of protein
When the protein is constructed, it plays a role in membrane structure and the transport of molecules across cell membranes. Protein provides support for the structure, stores amino acids, and is a main component in cell parts.
Structure function
The unique 3D structure of the protein determines exactly how it works - structure is directly related to function. For example, an antibody, which is a protein, can only react and destroy a specific type of virus. The same goes for receptor proteins and enzymes.
Receptor proteins
Receptor proteins can only accept certain molecules, such as the endorphin molecule which helps to relieve pain.
