Digestion and how nutrients reach the blood

Grade 9 Science Worksheet - Challenge Me

Circle the best answer.

1. Read this first

   Use this

   Model starch test (model data), 3 rows. Columns: minute, tube 1 amylase, near-neutral, tube 2 amylase with acid, tube 3 water only. 0, 100, 100, 100. 10, 30, 100, 100. 20, 5, 100, 100. Starch left is in relative units. Tube 2 has the acid level of the stomach.

2. 1.

   Ari reads a model card with three tubes. What does it show about amylase in stomach acid?

   • Acid stopped the amylase, since tube 2 stays at 100 like tube 3
   • The amylase in tube 1 was used up by minute 20, so its starch fell to 5
   • Acid sped up the amylase, since tube 2 lost the most starch
   • The three tubes lost starch, with tube 1 losing the most
3. 2.

   The 8.1 and 0.9 were worked out from 9 and 90 percent. Bo reads the water card. Which statement does it support?

   • The small intestine absorbs the full 9 L, so no water reaches the large intestine
   • The small intestine absorbs about 9 L, and the large intestine adds 0.9 L back
   • The small intestine absorbs about 0.9 L, leaving about 8.1 L for the large intestine
   • The small intestine absorbs about 8.1 L of the 9 L, leaving about 0.9 L
4. 3.

   Jun reads about a model tube of oil and lipase with no bile. How does oil digestion compare with a tube that has bile?

   • Faster, because larger globules give lipase more surface area to reach
   • Slower, because the oil stays in large globules and lipase reaches less
   • Faster, because lipase no longer has to share the oil with bile in the tube
   • The same, because chewing already finished the digestion of the oil in the mouth
5. 4.

   Kira reads the model. How much glucose does the flat strip take up in a minute, and how does that compare with the folded strip?

   • 60 units a minute, one third of the folded strip's 180
   • 180 units a minute, three times the folded strip's 60
   • 30 units a minute, the area of the flat strip without the rate
   • 60 units a minute, the same as the folded strip
6. 5.

   Luz reads a model in which pancreatic juice enters the small intestine without its bicarbonate. What happens to the acidic chyme and to the pancreatic enzymes?

   • The chyme stays acidic, so the pancreatic enzymes work more slowly
   • The chyme stays acidic, so the pancreatic enzymes are used up faster
   • The chyme is unchanged, since enzymes work the same at any level of acidity
   • The chyme turns basic, so the pancreatic enzymes work faster than before

7. Use this

   Notebook (model data), 4 rows. Columns: line, what it says. 1, Chewing breaks the bread into smaller pieces. 2, Salivary amylase starts changing starch into maltose. 3, In the stomach, pepsin finishes digesting the starch. 4, In the small intestine, pancreatic amylase continues the starch breakdown.

8. 6.

   Milo reviews a notebook on digesting bread. Exactly one line is wrong. Which line, and why?

   • Line 4, because amylase was used up in the mouth and cannot work again
   • Line 2, because the mouth just chews and starts no digestion
   • Line 3, because pepsin digests protein, not starch
   • Line 1, because chewing is chemical digestion

9. Use this

   Notebook (model data), 4 rows. Columns: line, what it says. 1, Amylase breaks starch into sugars. 2, Pepsin breaks protein into smaller peptides. 3, After it breaks one starch chain, an amylase molecule is used up. 4, Lipase breaks fats into fatty acids and monoglycerides.

10. 7.

    Pia reviews a notebook on enzymes. Exactly one line is wrong. Which line, and why?

    • Line 3, because an enzyme comes out unchanged and works again
    • Line 2, because pepsin, like amylase, also digests starch in bread
    • Line 1, because amylase breaks down the protein in beans and eggs
    • Line 4, because lipase makes amino acids from the protein in food

11. Organ card (real data from OpenStax)

    organ	main job
    Stomach	churns food and starts protein digestion with pepsin
    Small intestine	finishes digestion and absorbs nearly all nutrients through villi
    Large intestine	takes back water and salts and has no villi

12. 8.

    Ren compares three organs on a card. Which statement matches it?

    • The small intestine absorbs nearly all nutrients; the large one takes back water
    • The large intestine absorbs most nutrients, through the many villi in its long wall
    • The small intestine takes back water, and the large intestine finishes the digestion
    • The stomach absorbs most nutrients, after pepsin starts the protein digestion there

13. Enzyme card (real data from OpenStax)

    enzyme	made by	works in	breaks starch into
    Salivary amylase	salivary glands	mouth	maltose
    Pancreatic amylase	pancreas	small intestine	maltose

14. 9.

    Tala compares two enzymes on a card. Which statement is correct?

    • Both make maltose from starch; one works in the mouth, one in the small intestine
    • Pancreatic amylase is the same amylase carried down from the mouth
    • Salivary amylase digests starch, protein and fat, while pancreatic amylase digests starch
    • Salivary amylase works in the small intestine, and pancreatic amylase in the mouth

15. Absorption card (real data from OpenStax Anatomy and Physiology 2e)

    nutrient	share absorbed in the small intestine (percent)
    protein	95 to 98
    fats	about 95
    water	about 90

16. 10.

    Zee reads the absorption card. Which statement fits it?

    • The small intestine takes in about 95 percent of the water and 90 percent of the fats
    • The small intestine takes in about 90 percent of water and 95 percent of fats
    • The stomach takes in about 95 to 98 percent of the protein
    • The large intestine takes in about 95 percent of the fats and 90 percent of the water