Chapter 18 n Digestion Resource previous| 13 of 24 Chemical digestion of protein

Question

Chapter 18 n Digestion Resource previous| 13 of 24 Chemical digestion of proteins begins with the denaturation of proteins in the stomach, and continues with the subsequent breakdown of the resulting polypeptides into amino acids. Part A Which of the following statements about protein digestion are true? Check all that apply. Hints Hydrochloric acid in the stomach denatures proteins and activates some enzymes. O The primary structure of a protein is destroyed by hydrolysis. The tertiary and secondary structures of proteins unfold due to the action of the enzymes in the gut Pepsin is active only in an acidic environment. Some proteins are broken down into amino acids by the process of chewing. Most of the hydrolysis of polypeptides takes place in the small intestine. My.Answers Give Up Submit

Explanation / Answer

1) TRUE

2) FALSE

3) FALSE

4) TRUE

5) TRUE

6) TRUE

Protein digestion begins in the stomach with the action of an enzyme that we previously learned about called pepsin. Pepsin is the active protein-digesting enzyme of the stomach. When pepsin acts on the protein molecule, it breaks the bonds that hold the protein molecule together, called peptide bonds. So, you can think of pepsin as the enzyme that breaks peptide bonds. When these bonds are broken, you get chains of amino acids linked together called polypeptides. Since we know that the prefix 'poly' means 'many,' we can easily recall that a polypeptide is many amino acid units joined together. These polypeptides then move into your small intestine, where digestion will be completed by additional enzymes.

When you feel hungry, you typically think of protein as a food, such as eggs, milk, meat, nuts, or beans. Regardless of which way you want to look at protein, one fact remains, and that is that amino acids are the basic building blocks of protein. The term 'building block' is a good way to describe amino acids because they are literally used by your body for building biological substances. In fact, many of these biological substances are actually specialized proteins.

So, you might eat an egg for breakfast, and once you swallow it, enzymes break down the protein in the egg into amino acids. Then, those free amino acids recombine in different ways to form specialized proteins. These specialized proteins become different things, such as enzymes, or antibodies, or hormones. Or, they might become structural proteins, such as muscle proteins or collagen found in connective tissue.

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.