AP Biology : Understanding the Upper Digestive Tract: Mouth to Stomach

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #11 : Understanding The Upper Digestive Tract: Mouth To Stomach

Parietal cells in the stomach secrete which of these?

Possible Answers:

Hydrochloric acid

Pepsinogen

Mucus

Pepsin

Bile salts

Correct answer:

Hydrochloric acid

Explanation:

In the stomach, both hydrochloric acid and pepsinogen are secreted by gastric pits. Parietal cells in these pits secrete hydrochloric acid while chief cells in these pits secrete pepsinogen. Note that pepsinogen is inactive, and gets activated into pepsin via hydrochloric acid.

Example Question #12 : Understanding The Upper Digestive Tract: Mouth To Stomach

The esophagus is able to swallow liquids upside down, proving that swallowing is a process that does not depend on gravity. What is the name of this process?

Possible Answers:

esophageal emulsification

denaturation

flatulation

peristalsis

salivation

Correct answer:

peristalsis

Explanation:

Peristalsis is the correct answer here. Peristalsis is the process of muscles contracting and relaxing in order to facilitate movement.

Example Question #13 : Understanding The Upper Digestive Tract: Mouth To Stomach

Removal of the gall bladder from the human body would most likely result in which of the following?

Possible Answers:

An inability to digest fats properly

An inability to digest starch properly

An inability to digest carbohydrates properly

An inability to digest proteins properly

Correct answer:

An inability to digest fats properly

Explanation:

The gallbladder is found underneath the liver. The gallbladder is the storage place of bile, which helps to emulsify fats. Bile is necessary for the digestive system to break down fat. Removal of the gallbladder can result in fat malabsorption, which can present as loose stool.

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