Proteins-globular proteins Flashcards
What is a conjugated protein?
Globular proteins that have non protein groups (prosthetic groups) attached to them.
What is a prosthetic group
a non protein component that forms a permenant part of a functioning protein molecule
Define the term “globular protein”
has molecules of a spherical shape which are soluble in water and often have metabolic roles in an organism
Functions of haemoglobin: How does it carry O around the body
In the lungs, an O molecule binds to the Fe in each of the 4 haem groups in the haemoglobin molecule. When it binds, haemoglobin turns from a purple red colour to bright red.The O is released by haemoglobin when it reaches the tissues.
Functions of haemoglobin: How does it carry CO2 around the body
-20-25% of the co2 produced by bodily cells reacts with the amino group in haemoglobin to form a compound called carbaminohaemoglobin
-TWO OTHER WAYS BUT THATS COVERED IN THE BOHR SHIFT
Describe the primary structure of haemoglobin
compared to other proteins(like collagen) it contains a wide range of amino acids
Describe the secondary structure of haemoglobin
Most amino acids in haemoglobin from alpha helices, each polypeptide chain has 8 alpha helices connected by short beta pleated segments
Describe the tertiary structure of haemoglobin
Each polypeptide chain in haemoglobin contains a prosthetic group called haem(containing Fe2+).Hydrophobic R groups migrate to the centre of the structure and Hydrophilic R groups migrate to the outside of the structure
What type of bond does haemoglobin not contain
disulphide bridges( a type of covalent bond)
Describe the quaternary structure of haemoglobin
Its made of 4 sub units(Polypeptide chains, which all have one haem group) 2 alpha chains and 2 beta chains.
What does a haem group contain
an iron ion (Fe2+)
How many oxygen molecules can Haemoglobin carry
4 in total
could haemoglobin function without its haem groups
no , those groups are essential for the function of haemoglobin
Is the haem group exclusive to haemoglobins quaternary structure
yes , the haem groups are integrated into each of the 4 subunits (polypeptide chains)
What’s the difference between haemoglobins tertiary and quaternary structure
The tertiary structure refers to the 3D structure of individual polypeptide chains while quaternary structure refers to the arrangement of multiple polypeptide chains to form the haemoglobin molecule.
Why are globular proteins soluble in water and compact
hydrophobic R groups are kept away from the aqueous environment, whilst the hydrophilic R groups are on the outside of the protein.
What’s the function of insulin
It binds to glycoprotein receptors on the outside of muscle and fat cells to increase blood their uptake of glucose from the blood and to increase their rate of consumption of glucose
Why must insulin be soluble
Because it’s a hormone and it needs to be transported in blood
