Proteins Flashcards
How do you differentiate proteins from carbohydrates and lipids?
They contain nitrogen and (sometimes) sulfur, which both carbohydrates and lipids don’t have.
what elements do proteins contain?
C, H, O, N, S (carbon, hydrogen, oxygen, nitrogen and sulfur)
What does a protein consist of?
It is formed from many amino acids combined in a long chain.
What 3 things do each amino acid contain?
A basic amino group (-NH2) and acidic carboxyl group (-COOH), and a variable R-group
Properties of amino acids in terms of acidity + how it helps
Amino acids are both an acid and a base (amphoteric) and the bringing of amino acids together in different combinations produces proteins with very different properties–> able to fulfil the very different biological functions they have.
Structure of proteins–> state the first structure and describe it.
The primary structure. It is the long chain of amino acids
Structure of proteins–> state the 2nd structure and describe it.
secondary structure. either part or all of the polypeptide chain becomes coiled to produce a-helix or it becomes folded into b-sheets
Structure of proteins–> state the third structure and describe it.
tertiary structure.
precise, compact structure
unique to that protein that arises when the molecule is further folded and held in a particular complex shape
Structure of proteins–> state the 4th structure and describe it.
quaternary structure. 2 or more polypeptides become held together, forming a complex, biologically active molecule.
e.g. haemoglobin - 4 polypeptide chains (2 a-chains and 2 b-chains)
differences between globular protein and fibrous protein
globular:
- soluble
- have physiological roles in the body
- spherical structure
fibrous:
- insoluble
- have structural roles in the body
- linear structure
what are the 2 causes of denaturation in proteins?
exposure to heat, disrupting hydrogen and ionic bonds
pH changes alter ionic bonds
what is denaturation?
loss of three-dimensional structure of a protein
how does denaturation occur?
happens when the bonds that maintain the 3D shape are changed.
why are proteins not functional after denaturation?
many of the properties and uses of proteins within cells and organisms depend on their particular shapes. When the shape changes, the proteins cease to be functional
what is a dipeptide made of?
2 amino acids reacting together by condensation.
more specifically, amino group of 1 amino acid and carboxyl group of another amino acid
