Question 1

Which of the following best describes the chemical reaction that forms a dipeptide from two amino acids?

Accepted Answer

The -$$NH_3^+ $$group of one amino acid forms an amide bond with the carboxylate (-COO^-) group of another amino acid. $$H_2O is $$removed to form the bond.

Question 2

What is the overall charge on a zwitterion at its isoelectric point?

Accepted Answer

Neutral

Question 3

Which of the following best explains why a zwitterion is electrically neutral?

Accepted Answer

It contains an equal number of positive and negative charges.

Question 4

During protein synthesis, which type of bond is formed between amino acids, and what is released as a byproduct?

Accepted Answer

A peptide bond is formed and $$H_2O is $$released.

Question 5

Which of the following statements about peptide bond formation is correct?

Accepted Answer

It is a dehydration synthesis reaction.

Question 6

A patient’s blood sample shows a high concentration of amino acids in their zwitterionic form. What is the most likely pH of the blood sample?

Accepted Answer

Near the isoelectric point of the amino acids

Question 7

Which of the following is a direct consequence of the formation of a peptide bond between two amino acids?

Accepted Answer

The resulting molecule has one fewer water molecule than the sum of the two amino acids.

Question 8

If a mutation causes an amino acid to lose its ability to form a zwitterion, what is the most likely effect on protein structure?

Accepted Answer

The protein may lose its ability to maintain proper folding due to altered charge interactions.

Question 9

Which of the following best describes the process of hydrolyzing a dipeptide?

Accepted Answer

Adding $$H_2O to $$break the peptide bond, resulting in two free amino acids.

Question 10

A researcher is synthesizing a tripeptide in the lab. How many molecules of water are released during the formation of this tripeptide from three amino acids?

Accepted Answer

2

Question 11

Which functional groups are directly involved in the formation of a peptide bond?

Accepted Answer

The amino group (-$$NH_3^+) $$and the carboxyl group (-COO^-)

Question 12

Which of the following best explains why peptide bonds are stable under physiological conditions?

Accepted Answer

Peptide bonds have partial double-bond character due to resonance.

Peptide Bond Formation and Zwitterion Charge – Biochemistry Study Guidance

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