Human nutrition：練習題

Which term describes the process of taking substances, such as food and drink, into the body through the mouth?

In the human digestive system, where is amylase secreted and where does it carry out its primary function of breaking down starch into simple reducing sugars?

A student incubates a starch suspension with amylase at \( 37^\circ\text{C} \) for one hour. Which result would be expected when Benedict’s solution is added to the mixture and heated?

Which dietary component is essential for providing the body with roughage to help prevent constipation by moving food through the alimentary canal?

In the human digestive system, what is the biological significance of increasing the surface area of food during physical digestion?

Identify the mineral ion required for the production of haemoglobin and state the name of the condition caused by its deficiency in the diet.

Describe the observations for a positive result when testing a food sample for reducing sugars using Benedict’s solution, including the initial and final colour changes.

Explain the specific role of chemical digestion in the human body and why it is essential for the process of absorption.

The human digestive system consists of the alimentary canal and several associated organs that assist in the breakdown of food.

(a) Starting from the mouth, list the next three organs of the alimentary canal in the order that food passes through them.
(b) Describe the specific role of bile in the digestion of fats and oils, and state where bile is stored before its release into the small intestine.
(c) Define the term absorption in the context of the digestive system.

Chemical digestion is a complex process involving specialized proteins called enzymes that break down large insoluble molecules.

(a) Identify the four chemical elements that make up all protein molecules, including enzymes.
(b) Using the concept of a complementary shape, explain why a protease enzyme is able to digest protein but is unable to digest starch.
(c) In the stomach, hydrochloric acid is secreted. Explain how this acid contributes to the efficient digestion of proteins by enzymes like pepsin, and identify the organ where lipase is secreted to continue the digestion of fats.