What are the monomer units of proteins?
Amino acids. There are 20 different amino acids that combine to form proteins.
What type of covalent bond links amino acids together?
Peptide bond
What are the two ends of a polypeptide chain called?
N-terminus (amino end) and C-terminus (carboxyl end)
What is the central principle relating protein structure to function?
Structure begets function - a protein’s function is dependent on the shape it takes
List the 7 major functions of proteins
) Enzymes, 2) Trans-membrane transport proteins, 3) Defensive proteins (antibodies), 4) Signal proteins (hormones & receptors), 5) Movement (muscle tissue), 6) Structural (collagen), 7) Storage proteins
What is the basic structure of an amino acid? Draw
A central alpha carbon bonded to: an amino group, a carboxyl group, a hydrogen, and a side chain (R group)
What makes amino acids different from one another?
Their side chains (R groups), which differ in their chemical properties
What are the three categories of amino acid side chains?
1) Nonpolar side chains, 2) Polar side chains, 3) Electrically charged side chains (acidic or basic)
What is primary structure?
The unique sequence of amino acids in a polypeptide chain
What is secondary structure?
Coils and folds in the polypeptide chain, including alpha helices and beta sheets
What is tertiary structure?
The 3D shape formed by interactions among various side chains (R groups)
What is quaternary structure?
The structure formed when a protein consists of multiple polypeptide chains
What determines a protein’s overall structure?
The amino acid sequence (primary structure) determines how the protein will fold and its final shape
What happens when there is an incorrect amino acid sequence?
It leads to “misspelled” proteins with active site disruptions and loss of function, which can cause diseases like phenylketonuria and lactose intolerance
What is denaturation?
When a protein unravels and loses its shape due to alterations in pH, salt concentration, temperature, or other environmental factors
What happens to a denatured protein?
t becomes biologically inactive and cannot perform its function
What interactions stabilize tertiary structure?
Interactions between R-groups (side chains) of amino acids
Why is the analogy “structure begets function” important for proteins?
Because a protein’s specific 3D shape determines what function it can perform - if the shape is disrupted, the protein cannot function properly
What is a polypeptide
A chain of amino acids linked by peptide bonds; another name for a protein
Name two examples of diseases caused by nonfunctional enzymes due to incorrect amino acid sequences
Phenylketonuria and lactose intolerance
What do enzyme proteins do?
Catalyze (speed up) chemical reactions in the body
What do trans-membrane transport proteins do?
Embedded in cell membranes, they move substances across the membrane into or out of cells
What do defensive proteins (antibodies) do?
Protect the body by recognizing and binding to foreign invaders like bacteria and viruses
What do signal proteins do? Give examples.
end messages between cells. Examples include hormones (send signals) and receptors (receive signals)
