Proteins Flashcards
How many amino acids are needed to form a secondary structure protein?
Roughly 20
Describe primary structure proteins
Unique linear sequences of amino acids. The sequence is dictated by DNA. They do not yet have a function
How much DNA is in each cell?
About one metre
What causes primary structure proteins to take on a secondary structure?
Hydrogen bonding between amino acids within the same polypeptide chain but some distance apart
What are the two types of secondary structures in proteins?
A helixes and β-pleated sheets. Either could occur. They still have no function
Describe the α helix structure of secondary structure proteins
Due to hydrogen bonds between the amide group of one residue and the carboxyl group of another residue not far away in the same polypeptide
What shape do α helix secondary structure proteins take?
Spiral
Describe β-pleated sheets
Due to hydrogen bonding between amide and carboxyl groups where the amino acid residues are on different polypeptides or on the same polypeptide where the chain has folded back on itself such that the two parts of the strand involved are lying side by side
What shape does a β-pleated sheet secondary structure protein take on?
Paper folded in on itself
What determines the function of a protein?
The shape of its amino acid configuration
What are the types of amino acids?
20 total amino acids. 9 essential (must be supplemented by our diet) and 11 non-essential (created by the body)
What bonds stabilize the structural development of secondary structure proteins?
Disulphide bridges
Describe a tertiary structure of a protein
The three dimensional shape assumed by a polypeptide chain. It twists and folds on itself due to chemical interactions and has a small functional area called an active zone
What chemical interactions determine the shape of tertiary structure proteins?
Ionic bonds, hydrogen bonds, disulphide bridges, hydrophobic interactions, and proline kinks
How do amino acids form ionic bonds in tertiary structure proteins?
Positively charged radical groups attach to negatively charged R groups
How do amino acids form hydrogen bonds in tertiary structure proteins?
Two polar radical groups attach
How do amino acids form disulphide bridges in tertiary structure proteins?
Two cysteine amino acids form a covalent bond together on the same polypeptide chain
What causes hydrophobic interactions in tertiary structure proteins?
Non-polar radical groups interacting and folding in water
What determines the shape of a tertiary structure protein?
The chemical interactions which comprise it, such as ionic bonds, hydrogen bonds, disulphide bonds, and hydrophobic interactions
What degree structure of a protein is the first functional protein?
Tertiary structure protein
What are the functions of amino acids?
Break down food, grow and repair tissue, build muscle, provide energy source, create hormones
Describe a quaternary structure protein
When a functional protein is composed of two or more polypeptides that fit together in a specific arrangement. They serve a more complex function. Examples include insulin, composed of two polypeptide chains and hemoglobin, composed of four
Describe the denaturing of proteins
Gently heating, changing the pH, or certain chemical treatments can cause a protein to coagulate and lose its function. This is because a protein’s shape determines its function
What is the basic structure of an amino acid?
Amino group — R group — carboxyl group
H H O
| | ǁ H+ — N — C — C — O-
| |
H R
