Question 1

Which level of protein structure is directly represented when drawing a peptide using only the sequence of amino acids?

Accepted Answer

Primary structure

Question 2

When drawing a peptide backbone, which atoms are typically included in the backbone for each amino acid residue?

Accepted Answer

Alpha carbon ($$\mathrm{C}_\alpha$$), amine nitrogen ($$\mathrm{N}$$), and carbonyl carbon ($$\mathrm{C})$$

Question 3

What is the correct order of steps when drawing a peptide from its primary sequence?

Accepted Answer

Draw backbone, add C=O and N-H groups, then add R-groups

Question 4

In a peptide, the bond formed between the carboxyl group of one amino acid and the amine group of the next is called:

Accepted Answer

Peptide bond

Question 5

Given the peptide sequence A-L-A, how many peptide bonds are present?

Accepted Answer

2

Question 6

If you are drawing the peptide S-T-R-I-V-E, how many backbone nitrogen atoms will be present?

Accepted Answer

6

Question 7

Which functional group is found at the N-terminus of a peptide?

Accepted Answer

Amine group ($$-\mathrm{NH}_2)$$

Question 8

When drawing the peptide backbone, which atom is bonded to both the amine group and the carboxyl group in each amino acid?

Accepted Answer

Alpha carbon ($$\mathrm{C}_\alpha)$$

Question 9

A student is drawing a peptide and forgets to add the R-groups. What is missing from their drawing?

Accepted Answer

The side chains that define each amino acid

Question 10

Which of the following best describes the chemical reaction that forms a peptide bond?

Accepted Answer

Condensation (dehydration synthesis)

Question 11

If a peptide is composed of 4 amino acids, how many R-groups will be present in its structure?

Accepted Answer

4

Question 12

Which atom is NOT part of the peptide backbone?

Accepted Answer

R-group carbon

Question 13

A peptide with the sequence D-H-A-W will have how many carbonyl groups in its backbone?

Accepted Answer

4

Question 14

Which of the following is the correct general formula for a peptide bond?

Accepted Answer

$$\mathrm{CO}-\mathrm{NH}$$

Question 15

When drawing a peptide, why is it important to identify the N-terminus and C-terminus?

Accepted Answer

To correctly orient the sequence and show directionality

Question 16

Which step in peptide drawing involves adding the remaining hydrogens and nitrogen atoms to the backbone?

Accepted Answer

Step #3

Question 17

If a peptide sequence is P-C-Y-A-F-O-K, how many backbone carbon atoms will be present?

Accepted Answer

7

Question 18

Which of the following is a correct representation of the peptide backbone for a tripeptide?

Accepted Answer

$$\mathrm{N}-\mathrm{C}_\alpha-\mathrm{C}-\mathrm{N}-\mathrm{C}_\alpha-\mathrm{C}-\mathrm{N}-\mathrm{C}_\alpha-\mathrm{C}$$

Question 19

Which group is transferred from one amino acid to another during peptide bond formation?

Accepted Answer

Hydroxyl group ($$-\mathrm{OH})$$

Question 20

A peptide is drawn with the sequence A-H-M-H-I-G-H. How many peptide bonds are present?

Accepted Answer

6

Drawing Peptides: Steps and Practice for Primary Protein Structure

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