Proteins (Types of proteins - Globular Proteins) Flashcards
Give 3 characteristics of globular proteins
compact
water soluble
roughly spherical
Define globular protein
spherical, water-soluble proteins
Why are globular proteins water soluble?
TERTIARY structures are folded so that the hydrophobic R-groups are kept away from the aqueous environment -hydrophilic R-groups are on the outside
Why is the solubility of globular proteins important?
The solubility allows globular proteins to perform vital functions in the body, such as chemical reactions, immunity, and muscle contraction.
What is an example of a globular protein and its function?
Insulin is a globular protein that regulates blood glucose levels. It is soluble in the bloodstream and has a precise shape to bind to specific receptors on cell membranes.
What are globular proteins used for?
regulating many processes
Give examples of the processes globular proteins regulate
muscle contraction
immunity
chemical processes
Are conjugated proteins a type of globular protein?
Yes.
What are conjugated proteins?
Conjugated proteins are globular proteins that contain a non-protein component called a prosthetic group. Proteins without prosthetic groups are called simple proteins.
What do conjugated proteins contain?
A non-protein prosthetic group
What is a prosthetic group and give an example?
A prosthetic group is a non-protein component that binds to a protein, such as a metal ion or molecule derived from vitamins.
An example is the haem group, which contains an iron ion (Fe²⁺).
Give an example of 2 conjugated proteins
Haemoglobin
Catalase
What is the function of haemoglobin?
Carries oxygen in the blood in erythrocytes
What polypeptide sub units is haemoglobin made up of?
2 alpha-helices 2 beta-pleated sheets
How many subunits make up haemoglobin?
4
What does each haem group contain?
Iron 2+ ion
What does each subunit of haemoglobin contain?
A haem group
How do haem groups allow erythrocytes to carry out their function?
Iron ions in haem groups can reversibly combine with an oxygen molecule
How many oxygen atoms can one haemoglobin molecule carry?
8- remember ATOMS not MOLECULES
How does haemoglobin transport oxygen?
Haemoglobin is a quaternary protein with four polypeptide sub units (two alpha and two beta) and prosthetic haem groups.
Each haem group can bind reversibly with an oxygen molecule, allowing haemoglobin to pick up oxygen in the lungs and release it in tissues.
What is catalase and how does it function? What does it produce?
Catalase is a quaternary protein containing haem groups, which allows it to catalyse the breakdown of hydrogen peroxide, a harmful by-product of metabolism, into water and oxygen.
What type of protein is catalase?
Conjugated
What type of prosthetic group does catalase contain?
Haem
How many haem groups does catalase contain?
4
