2.4 Proteins Flashcards
What is a polypeptide?
Chains of amino acids made by condensation reactions. These reactions occur on ribosomes by translation. They are the primary components of proteins.
How many different amino acids are there? What is different about each one?
- 20 amino acids.
- Different R groups.
How does the diversity of amino acids lead to infinite possibilities of polypeptides?
- Can be tens of thousands of polypeptide lengths
- For n amino acids, there are 20^n unique polypeptides possible
How many DNA bases are needed to code for an amino acid?
Three
What is the open reading frame?
The base sequence that actually codes for the polypeptide.
What is the primary protein structure? What bonds hold it in place? Anything further?
- Sequence of amino acids.
- Peptide bonds from condensation
- Primary structure is determined by DNA base sequence in genes
What is the secondary protein structure? What bonds hold it in place?
- Formation of alpha-helices and beta-pleated sheets
- Polar covalent bonds and hydrogen bonds between carboxyl group and amine group
What is the tertiary protein structure? What bonds hold it in place? Anything further?
- Further folding of the polypeptide stabilized by interactions between R groups.
- Ionic bonds, hydrogen bonds, disulphide bridge, hydrophobic R group interactions
- Three dimensional structure of the protein gives the protein its function, at least after tertiary structure
What is the quaternary protein structure? What bonds hold it in place?
- Two or more globular proteins
- R group interactions
Distinguish between polypeptides and proteins.
Proteins consist of one or more polypeptides linked together
How are globular proteins different than fibrous ones?
Fibrous proteins are elongated, usually with a heated structure, while globular proteins are intricate and usually include helical and sheet-like parts
What is a proteome?
All of the proteins produced by a cell, a tissue, or an organism
