Proteins Flashcards
What are amino acids made up of?
(alpha) Carbon bonded to a:
hydrogen
R group
NH2- Amine group (amino)
COOH- carboxyl group (acid)
How many naturally occurring amino acids is there?
20- vary according to side groups
10 of these are essential amino acids in humans because the human body cannot produce them and they are obtained from the diet
what can the NH2 group do?
They can act as a base, which means it can accept an H+ in acidic conditions
so sometimes an NH2 group becomes an NH3+ group
what can the COOH group do?
The COOH group acts as an acid, which means it can donate an H+ in alkaline solutions
so sometimes a COOH group becomes a COO- group
Where does a peptide bond occur?
Between the carboxyl and the amine group of an amino acid
what do we call many polypeptide which are combined together into one molecule?
a protein
what are the two end terminals at the end of each polypeptide chain?
The N-terminal: amine terminal
The C-terminal: carboxyl terminal
what is the primary structure of a protein?
The primary structure of a protein is the sequence of amino acids in a polypeptide chain.
The primary structure is determined by the gene encoding the protein
what is the primary structure of a protein?
The primary structure of a protein is the sequence of amino acids in a polypeptide chain.
The primary structure is determined by the gene encoding the protein
what happens if there is a change in the nucleotide sequence of the genes encoding region?
It may lead to a different amino acid being added to the growing polypeptide chain
A change in the amino acids in a protein could change the proteins structure and function
what happens in the polypeptide chain with the oppositely charged ions?
Thé oxygens have a partial negative charge whilst the hydrogens have a partial positive charge meaning they are polar.
Due to these attractions they form hydrogen bond pulling the polypeptide chain collider together.
what types of secondary structures are there?
the beta pleated sheet
the alpha helix
dependant on the primary structure in the polypeptide chain
why does the secondary structure fold?
The folding happens because the hydrogen bonds form between the groups of peptide bonds
what type of bonds are present in the tertiary structure?
side groups of any two amino acids can form:
hydrogen bonds (partial negative + partial positive)
ionic (negative +positive charge)
Disulfide (bridges) bonds (cysteines, sulfhydryl groups)
what is the tertiary structure caused by?
It is caused by bonds between the side groups of amino acids int he polypeptide chain
what is the tertiary structure?
The 3 dimensional folding of the whole polypeptide chain
what is the quaternary structure?
the shape we get when two or more 3D polypeptide chain join together
Haemoglobin
Found in red blood cells of our blood
It has a quaternary structure that is made up of four polypeptide chains, called globins.
Now, because harm groups contain iron, each of them can bond one molecule of oxygen
every one molecule of haemoglobin, can carry four molecules of oxygen to all the vital organs in our body
Haemoglobin
Found in red blood cells of our blood
It has a quaternary structure that is made up of four polypeptide chains, called globins.
Now, because harm groups contain iron, each of them can bond one molecule of oxygen
every one molecule of haemoglobin, can carry four molecules of oxygen to all the vital organs in our body
what do scientists call a non-protein part in a protein? such as a haem group
A prosthetic group
a protein with a prosthetic group is called a conjugated protein
what structure do globular proteins have?
Globular proteins are compact, roughly spherical (circular) in shape
-soluble in water
why do globular proteins form a spherical shape when folding into their structure?
Their non-polar hydrophobic R groups are orientates towards the centre of the protein away from the aqueous surroundings
Their polar hydrophilic R groups orientate themselves on the outside of the protein