Base your answer to the following question on the diagram below, which represents the human digestive system. Most reabsorption of water occurs within structure

A. F

B. G

C. C

D. D

Answer Explanation:

Most reabsorption of water occurs in the large intestine, F.

Therefore, the Correct Answer is A.

Q #1: Which of these nutrients is absorbed mainly in the duodenum?

A. glucose

B. iron

C. sodium

D. water

Answer Explanation

b) iron

- Correct: Iron is mainly absorbed in the duodenum, particularly in its proximal portion. Iron absorption occurs through active transport mechanisms facilitated by specialized transport proteins in the duodenal epithelial cells. Once absorbed, iron can be transported into the bloodstream and utilized for various physiological functions, including the production of hemoglobin and other iron-containing proteins.

a) glucose

- Incorrect: Glucose is primarily absorbed in the small intestine, but its absorption occurs mainly in the jejunum and ileum rather than the duodenum. Glucose is absorbed through facilitated diffusion and active transport mechanisms in the epithelial cells lining the small intestine.

c) sodium

- Incorrect: Sodium is absorbed throughout the small intestine, including the duodenum, jejunum, and ileum. Its absorption occurs through active transport mechanisms in the epithelial cells lining the intestinal mucosa, primarily in conjunction with glucose and other nutrients.

d) water

- Incorrect: Absorption of water indeed takes place in the large intestine, particularly in the colon.
Q #2: Which structure produces a substance that aids in the mechanical breakdown of fats?

A. liver

B. thyroid gland

C. testes

D. pituitary gland

Answer Explanation

A) liver

- Correct: The liver produces bile, a substance that aids in the mechanical breakdown of fats. Bile is stored in the gallbladder and released into the small intestine when needed. Bile emulsifies large fat globules into smaller droplets, which increases the surface area for the action of digestive enzymes. This process facilitates the breakdown of fats into smaller molecules for digestion and absorption.

B) thyroid gland

- Incorrect: The thyroid gland produces hormones that regulate metabolism but is not directly involved in the mechanical breakdown of fats.

C) testes

- Incorrect: The testes are reproductive organs responsible for the production of sperm in males and do not play a role in the mechanical breakdown of fats.

D) pituitary gland

- Incorrect: The pituitary gland is a master gland that produces and regulates various hormones but is not involved in the mechanical breakdown of fats.
Q #3: The enzyme pepsin is produced in the cells of the stomach but not in the cells of the small intestine. The small intestine produces a different enzyme, trypsin. The reason that the stomach and small intestine produce different enzymes is that the gene that codes for pepsin is

A. in the cells of the stomach, but not in the cells of the small intestine

B. expressed in the stomach but not expressed in the small intestine

C. mutated in the small intestine

D. digested by the trypsin in the small intestine

Answer Explanation

Enzymes are proteins that catalyze specific biochemical reactions in living organisms.

The production of enzymes is regulated by gene expression, where specific genes are activated (expressed) to produce particular enzymes in different cells or tissues.

In this case, the gene responsible for coding the enzyme pepsin is expressed in the cells of the stomach, leading to the production of pepsin in the stomach.

Conversely, the gene for trypsin is expressed in the cells of the small intestine, resulting in the production of trypsin in the small intestine.

Therefore, the reason that the stomach and small intestine produce different enzymes is due to the differential gene expression in these respective tissues.

Free Access on TEAS 7 Exams and Study Notes

Access to all TEAS 7 Exams
Performance Tracking and Analysis
Well Documented and Explained Questions and Answers
2000+ Questions and Correct Answers: Answers Well Explained
Libary of Detailed StudyNotes
Topical Questions and Answers on Examinable topics

Join Now

Base your answer to the following question on the diagram below, which represents the human digestive system. Most reabsorption of water occurs within structure

More Questions on TEAS 7 Science

Q #1: Which of these nutrients is absorbed mainly in the duodenum?

Answer Explanation

Q #2: Which structure produces a substance that aids in the mechanical breakdown of fats?

Answer Explanation

Q #3: The enzyme pepsin is produced in the cells of the stomach but not in the cells of the small intestine. The small intestine produces a different enzyme, trypsin. The reason that the stomach and small intestine produce different enzymes is that the gene that codes for pepsin is

Answer Explanation

Free Access on TEAS 7 Exams and Study Notes

TEAS 7 Exams (Q&A)

TEAS 7 Study Notes

TEAS 7 Topical Tests

TEAS 7 Study Guides

Quick Links

Refer a Friend