Zusammenfassung der Ressource
Proteins
- Amino acids and
polypeptides
- amino acids
condensed into
polypeptides
- on ribosomes by translation
- main or only
component
of proteins
- condensation reaction: anime
group (NH2) of one aa and
carboxyl group (COOH) of one aa
- water eliminated;
peptide bond formed
- dipeptide = 2
aa bonded by a
peptide bond
- polypetide =
chain of many aa
- oligopeptides =
less than 20 aa
- The diversity
of amino acids
- 20 diff aa
- carbon atom in centre linked
to amine group, carboxyl
group, hydrogen atom
- C bonded to diff R
group in every aa
- aa chemically diverse due to
wide range of R groups
- polypeptides may
contain modified aa
- Polypeptide diversity
- aa can link in any sequence
so polypeptides diverse
- ribosome can make peptide
bond between any aa
- number of aa = n
possible
sequences = 20^n
- Genes and
polypeptides
- aa sequence
coded by genes
- polypeptide structure stored
in gene's base sequence
- most gene cells
store aa sequences
- three bases needed
to code for every aa
- open reading frame =
base sequence coding
for polypeptides
- open reading frames only occupy
small proportion of total DNA
- Proteins and polypeptides
- proteins = single or many
linked polypeptides
- Integrin can fold any way
- Collagen is twisted like
a rope for structure
- 4 parts of haemoglobin interact
- Protein conformations
- 3D conformation
determined by
aa sequence
- 3D structure
- fibrous proteins
elongated with
repeating structure
- folding prevented
- globular proteins are
intricate with helical
or sheet-like parts
- stabilized by
R groups of aa
- fold as created
- if water soluble - hydrophobic
R inside; hydrophilic R outside
- regions with hydrophobic R
outside attracted to
hydrophobic membrane centre
- Protein functions
- catalysis
- muscle contraction
- cytoskeletons
- tensile strengthening
- blood clotting
- Transport of
nutrients and gases
- Cell adhesion
- Membrane transport
- Hormones
- Receptors
- Packing of DNA
- Immunity
- other uses in book (non-biological)
- Proteomes
- unique in every individual
- all proteins produced
- separated by gel electrophresis
- variable and different even though
strong similarities in species