Please enable JavaScript.
Coggle requires JavaScript to display documents.
Topic 2.4: Protein (Polypeptides
chains of amino acids
main component…
Topic 2.4: Protein
Polypeptides
- chains of amino acids
- main component of proteins
Amio acids 
Linked together by ribosomes during translation
There are 20 amino acids in polypeptides synthesized on ribosomes
R-group makes each amino acids chemically different
==> determine the characteristics of polypeptides
Why do most organisms make proteins using the same 20 amino acids?
1) The 20 a.a were produced by chemical properties before the origin of life --> all organisms used them
2) The 20 a.a is ideal --> natural selection will always favor organisms that use them
3) Life evolved from a single ancestral species that used the 20 a.a
Condensation
reaction involves amino group and carboxyl group, in which water is eliminated and peptide bond between 2 amino acids is formed
-
-
Proteome
- all of the proteins produced by a cell, a tissue or an organism
- variable
- none of us have identical proteomes
Conformations
- 3D structure which is determined by a.a sequence
- Shape and chemical properties are depended on R-groups
Functions
-
-
Spider silk: A fiber spun by spiders and used to make webs (by weight, is stronger than kevlar and steel)
-
-
-
-
Immunoglobulins: Antibodies produced by plasma cells that are capable of targeting specific antigens
-
-
Cytochrome: A group of proteins located in the mitochondria and involved in the electron transport chain
-
Rhodopsin: A pigment in the photoreceptor cells of the retina that is responsible for the detection of light
-
-
-
-
-
Genes
A cell produces polypeptides w/ thousands of different sequences which are coded in the base sequence of gene
--> 3 bases of the gee are needed to code for each amino acid in polypeptide #
Base sequence
- located at both ends and middle of gene sequences
- this is the only sequence that actually codes for polypeptide
-
Denaturation
- a structural change in a protein that results in a permanent loss of biological properties.