Proteins Flashcards
What are proteins made of?
Amino acids which have two functional groups (NH2 and COOH) and an R-group (lots of variations)
What bonding is in amino acids?
Peptide bond
O=C-N-H
Which is formed by covalent bonds
Define dipeptide:
A molecule made from two amino acids
Define polypeptides:
A molecule made from many amino acids
Define R-groups:
The group that causes variation in amino acids and gives each amino acid it’s distinctive properties.
What is the primary structure of proteins?
The sequence of amino acids in a polypeptide or protein which is determined by DNA in the cell.
This sequence determines the bonding in higher levels of the structure.
What is secondary structure in a protein?
The structure of a protein molecule resulting in the regular coiling or closing of the chain of amino acids.
Alpha-helix and beta-pleated sheets.
What is tertiary structure of proteins?
The compact structure of a protein molecule resulting from the 3D coiling of the chain of amino acids.
Caused by bonds between R-groups
Very precise, specific structures held by different bonds.
What are quaternary structures of proteins?
The 3D arrangements of two or more polypeptide chains and non protein components can also form part of it.
What are globular proteins?
A protein whose molecules have folded into relative spherical shapes and is water soluble (because hydrophilic amino acids are on the outside) and metabolically active.
What are fibrous proteins?
A protein whose molecules have a relatively long, thin structure that id generally insoluble and metabolically inactive.
Function is structural
What is haemoglobin?
An oxygen-carrying pigment found in red blood cells that has a quaternary structure.
Alpha- globin and beta-globin
What is collagen?
An insoluble fibrous that consists of three polypeptide chains that are held in a loose helix structure that wrap around and form a triple helix.
The triple helix structures lay parallel to one another
