Wheat, barley and rye all contain gluten. Outline how a protein such as gluten is digested.

Discuss the roles of the enzymes secreted by the pancreas during digestion.

The photomicrograph drawing shows a longitudinal section of the small intestine.

[Source: Henry Gray (1918) Anatomy of the Human Body]

What is the function of the tissue layers labelled X and Y?

A. Secretion of digestive enzymes

B. Absorption of digested food

C. Transport of absorbed foods

D. Movement of food in the intestine

The diagram shows a cross section through the small intestine of a mammal. Which label points to the mucosa?

[Source: JOSE LUIS CALVO MARTIN & JOSE ENRIQUE GARCIA-MAURIÑO MUZQUIZ / www.istockphoto.com.]

The diagram shows the human digestive system. Where are lipids digested?

[Source: BruceBlaus/Wikimedia. File licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/)]

Where in the digestive system are lipids broken down?

[Source: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health. The Digestive System
[online] Available at: https://www.niddk.nih.gov/news/media-library/11172. Source adapted.]

The micrograph is of a longitudinal section through the small intestine. Which letter represents the circular muscle layer?

[Source: Henry Gray (1918) Anatomy of the Human Body]

Explain the adaptations of the small intestine to its function.

The micrograph shows part of a cell.

The diagram shows the human digestive system. Which organ is responsible for the majority of the absorption of digested food?

[Source: BruceBlaus/Wikimedia. File licensed under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/)]

The photomicrograph shows a section through a human small intestine.

[Source: Chiodini RJ, Dowd SE, Chamberlin WM, Galandiuk S, Davis B,
Glassing A (2015) Microbial Population Differentials between Mucosal and Submucosal Intestinal Tissues in
Advanced Crohn’s Disease of the Ileum. PLoS ONE 10(7): e0134382. https://doi.org/10.1371/journal.pone.0134382.]

Which statement corresponds to the labelled structures?

A. X moves food along the intestine.

B. Y is the mucosa.

C. Y contains lacteals.

D. Z causes peristalsis

Outline the significance of surface area to volume ratio in the limitation of cell size.

The image is an electron micrograph of the lining of the small intestine.

(i) Label the microvilli using the letter M and a nucleus using the letter N.

(ii) State the function of the goblet cell.

(iii) Deduce, with a reason, whether or not the goblet cell is likely to divide.

Predict, with a reason, whether the amino acid composition of yellow mealworms or cattle is more suitable for a human diet.

Distinguish between the amino acid contents of yellow mealworms and cattle.

Explain how amino acids in casein could reach the liver, starting from the moment when the person takes a bite of pastry cream pie.

Humans rely on carbohydrates for much of their energy. Outline the process of digestion and absorption of starch in the human digestive system.

Outline how proteins are digested and the products of protein digestion absorbed in humans.

A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken?

A. Mouth

B. Stomach

C. Small intestine

D. Gall bladder

What are these structures?

[Source: Burgstedt | Dreamstime.com]

A. Fatty acids in the small intestine

B. Bacteria in the large intestine

C. Villi in the small intestine

D. Feces egested from the large intestine 

Outline the functions of the villi in the small intestine.

A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken?

A. Mouth

B. Stomach

C. Small intestine

D. Gall bladder

Explain the consequences of celiac disease for absorption of digested nutrients.

Congenital lactase deficiency is a type of lactose intolerance that occurs in infants. It is inherited in an autosomal recessive pattern. Calculate the chance of congenital lactose intolerance in a child whose parents are both carriers for the disorder, showing fully how you reached your answer.

Describe the processes involved in absorbing different nutrients across the cell membrane of villus epithelium cells lining the small intestine.

Birds and mammals maintain constant body temperature despite considerable losses of body heat to the environment. In insects such as mealworms, body temperature is variable and is often the same as the temperature of the environment or only slightly above it. Analyse the data in the bar charts, using this information.

Explain the action of enzymes in digestion and the different roles of at least two named enzymes that are produced in the pancreas.