Nokea
Chemical digestion of carbohydrates begins in the........... whereas chemical digestion of proteins begins in the...........
- A. Oral cavity; duodenum
- B. Stomach; oral cavity
- C. Stomach; duodenum
- D. Oral cavity; Stomach
Correct Answer: D
Rationale: Carbohydrate digestion starts in the oral cavity with salivary amylase, while protein digestion begins in the stomach with pepsin.
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Besides carbohydrates, proteins, fats, vitamins and minerals, what other nutrient does your body need for life?
- A. DNA
- B. chlorophyll
- C. water
- D. none of the above
Correct Answer: C
Rationale: Water is an essential nutrient required for all bodily functions.
Which of the following parts of the digestive system has the most important role in nutrient absorption?
- A. stomach
- B. esophagus
- C. large intestines
- D. small intestines
Correct Answer: D
Rationale: The small intestine is the primary site for nutrient absorption due to its large surface area and specialized structures like villi and microvilli.
The diagram shows a section through a villus. Y X What is a function of structure X and of structure Y?
- A. X: to absorb amino acids, Y: to digest starch
- B. X: to carry blood, Y: to secrete mucus
- C. X: to transport fats, Y: to secrete enzymes
- D. X: to transport glucose, Y: to help peristalsis
Correct Answer: A
Rationale: Structure X (epithelial cells) absorbs amino acids, while structure Y (goblet cells) secretes mucus.
Amino acids are absorbed in-
- A. Blood capillaries of villi
- B. Wall of rectum
- C. Lacteals and blood capillaries of villi
- D. Lacteals of villi
Correct Answer: A
Rationale: Amino acids are absorbed into the blood capillaries of the villi in the small intestine.
The pylorus is best described as the:
- A. Area of the stomach that accepts food from the esophagus
- B. Valve between the ileum and the cecum
- C. Terminal portion of the large intestine
- D. Area of the stomach that empties into the small intestine
Correct Answer: D
Rationale: The pylorus is the lower part of the stomach that connects to the duodenum.