The Structure Of Proteins Flashcards
what are peptides?
polymers made up of amino acid molecules. proteins are made up of peptides.
how many different amino acids do we have?
20
- 5 non essential as we can make them.
- 9 are essential and can only be achieved from food.
- 6 conditionally essential as need them as babies and growing children.
what bond is formed between amino acids?
a peptide bond.
what is the general structure of an amino acid?
- carboxyl group#
- amine group
- variable R group
where are proteins synthesised?
ribosomes.
what enzyme catalyses the formation of polypeptides?
peptidly transferase
what is the primary structure of a protein?
the sequence in which the amino acids are joined.
what determines the primary structure of a protein?
information carried within the DNA.
what bonds are involved in the primary structure of a protein?
peptide bonds.
what is the secondary structure of a protein?
the result of hydrogen bonds and forms at the regions along long protein molecules depending on the amino sequences. Alpha helix vs beta pleated sheets.
how is an alpha helix formed?
hydrogen bonds may form within the amino acid chain, pulling it into a coil shape (alpha helix)
how is a beta pleated sheet formed?
polypeptide chains may lie parallel to one another joined by hydrogen bonds, forming sheet like structures. the pattern formed by the individual amino acids causes the structure to appear pleated.
what is the tertiary structue of a protein?
the folding of a protein into its final shape.
what determines the tertiary structure of proteins?
the coiling or folding of sections into their secondary structures brings R-groups of different amino acids closer together so they are close enough to interact and further folding of these sectiosn will occur.
what interactions occur between R-groups?
- hydrophobic and hydrophilic interactions. weak interactions between polar and non-polar R groups.
- hydrogen bonds - these are weakened as the bonds form.
- ionic bonds - stronger than hydrogen bonds and form between oppositely charged R-groups.
- disulphide bonds. these are covalent and the strongest of the bonds but only form between R-groups that contain sulfur atoms.
