Which amino acid is negatively charged?

Which type of PTM usually occurs on the side chains of amino acids  S, T, or Y?

What is the formal charge on the nitrogen atom of the following chemical structure?    

In a groundbreaking study that earned Chris Anfinsen the 1972 Nobel Prize in Chemistry, researchers investigated the folding behavior of ribonuclease A, a small protein containing eight cysteine residues that normally form four specific disulfide bonds. The experiment involved completely denaturing the enzyme by incubating it in urea along with 2-mercaptoethanol, a reducing agent that breaks disulfide bonds. Under these harsh conditions, the protein lost its secondary and tertiary structure, and all disulfide bonds were reduced. Remarkably, when the urea and 2-mercaptoethanol were removed, ribonuclease A spontaneously refolded into its native conformation, reestablishing the correct disulfide bonds. This result demonstrated that the protein’s amino acid sequence alone contains all the information required for it to attain its native, functional three-dimensional structure. Based on the passage above, which of the following conclusions is best supported by the ribonuclease refolding experiment?

You must complete the _____________ quiz and post an initial _______________ by Thursday of the first week to avoid being dropped from the course as a “no show”.

Evaluate the function at the given value of the independent variable and simplify. f(x)  

When will the first exam be available?  

5. which of the following is the priority nursing intervention for this 28-year-old patient? 

6. A nurse is caring for a patient diagnosed with diabetic ketoacidosis (DKA) leading to metabolic acidosis. Which of the following arterial blood gas (ABG) findings should the nurse expect?

The energy of motion is referred to as