STEP – Grade 9 Biology
Human Digestive System Test
Name:………………………………...
Date:………………
Use the diagram above to answer questions 1 – 6. Circle the correct answer
1. Which letter indicates the organ that secretes hydrochloric acid and protease?
(a) A
(b) B (c) C (d) D (e) E (f) F
2. Which substance is normally absorbed by structure F?
(a) bile
(b) nutrients
(c) HCl
(d) water
3. The end products of protein digestion diffuse into the villi that are present in the lining of structure
(a)C
(b) G (c) F (d) D (e) I
4. In which structure does the initial hydrolysis of carbohydrates occur?
(a) A
(b) C (c) B (d)D
5. From which structure are glucose and amino acids normally absorbed into the blood vessels?
(a) C
(b) D (c) F (d) B
6. In which structure does chemical digestion of protein begin?
(a) D
(b) B (c) G (d) F
7. The digestion of proteins is completed in the
(a) stomach (b) small intestine (c) esophagus (d) large intestine
8. The least digestion of food occurs in the
(a) small intestine (b) mouth (c) esophagus (d) stomach
9. The taking in of food is called
(a) digestion (b) secretion (c) lubrication (d) ingestion
10. The chemical digestion of lipids or fats begins in the
(a) colon (b) lungs (c) stomach (d) mouth (e) small intestine
11. The breakdown of food an organism so it can be absorbed is called
(a) ingestion (b) digestion (c) secretion (d) excretion
12. Lipases, proteases, and carbohydrases are secreted into the small intestine from the
(a) liver (b) pancreas (c) mouth (d) large intestine
13. Which type of digestion occurs in the mouth when an individual chews a piece of bread?
(a) chemical digestion (b) mechanical digestion (c) both chemical and mechanical digestion (d) neither
chemical nor mechanical digestion
14. The diagram at right shows a particle of food being moved along the human
digestive tract by alternate waves of relaxation and contraction of the muscular
walls of the esophagus. Which process causes the movement of the food down
the esophagus?
(a) secretion (b) movement (c) absorption (d)
peristalsis
Use this diagram to answer questions 15 – 17.
The diagram represents the digestive system of a student who has eaten a sandwich
consisting of two slices of bread, chicken, lettuce, and mayonnaise.
15. The final reactions for the complete digestion of the bread would occur in organ
(a) 1
(b) 2 (c) 3 (d) 4 (e) 5
16. Which organ produces a substance that would be used in the emulsification of the lipids in the mayonnaise?
(a) 1
(b) 2 (c) 3 (d) 4 (e) 7
17. In which organs would chemical digestion of the chicken take place?
(a) 1 and 3
(b) 1 and 7
(c) 2 and 6
(d) 3 and 5
18. In the following table, name three enzymes that will digest the sandwich, the food groups they act on and the
substances produced. (6pts)
Enzyme
Acts on
Breaks down into
19. Describe digestion of the lettuce in the sandwich. (2 pts)
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(Total 25 points)