B1.2 Proteins Flashcards
Amino acids structure
- alpha carbon atom
- amine group (N and 2 H)
- carboxyl group (COOH)
- single hydrogen atom
- R (variable group)
By what type of reaction proteins are formed?
by condensation reaction
What parts of two amino acids attach?
amino and carboxyl group
What is the peptide bond?
bond between two amino acids (between amino and carboxyl group)
What is dipeptide and polypeptide?
two amino acids or more joined together
What quality of amino acids allows for almost inifinite number of combinations?
20 different amino acids with 20 different R groups can be arranged in different orders and length
Denaturation
Damage of the protein by external factor (pH or temperature)
Essential amino acids?
Amino acids that have to be included in the diet (9)
Non-essential amino acids?
The ones that our body is able to make (11)
What gives the diversity among the amino acids?
R-group - it ensure chemical diversity and gives amino acids different properties (e.g. acidic or basic, polar or non-polar, hydrophylic or hydrophobic)
Describe primary structure
-chain of amino acids in straight line (without folds)
-amino acids bonded by peptide bonds
Significance of primary structure of the protein
- DNA determines the primary structure
- the order determines how protein is later folded
Which parts of amino acids bond to each other in secondary structure?
Oxygen atom of one amino acid and hydrogen atom of the other amino acid bond by hydrogen bonds
Describe secondary structure
Folding like alpha helices (spiral) and beta-pleated sheets (zig-zag), stabilized by hydrogen bonds
Describe tertiary structure
Hydrogen bonds occur between R-groups of different amino acids
Bond between two cysteine amino acids
Covalent, disulfide bond (because the R-group of both amino acids contain sulfur that bind together)
Quaternary structure
2 or more separate protein chains bound together
Conjugated quaternary proteins
proteins that have other chemical groups attached
Non-conjugated quaternary proteins (e.g. insulin)
means that there are no additional chemical groups attached
Protein conjugation
a protein to which another chemical group is binded
Describe insulin
non-conjugated globular protein where 2 chains are binded by 2 disulfide bridge
Describe hemoglobin
- conjugated protein
- 4 polypeptide chains
- each chain contains heme group
Describe collagen
- non-conjugated
- fibrous protein
- 3 protein chains bound together into helix
How insulin’s globular shape helps carry out it’s function?
-stability
-mobility (easily moves around)
