Digestion and how nutrients reach the blood

Grade 9 Science Worksheet - Building Confidence

Circle the best answer.

1. 1.

   Ari follows a bite of bread along the tract map. Which organ goes in the blank box?

   • The liver, which makes bile for fat digestion
   • The pancreas, which sends enzymes into the small intestine
   • The rectum, which holds waste until it leaves
   • The stomach, which mixes food with acid and pepsin
2. 2.

   Bo reads the tract map with one helper organ. Which box is a helper that food does not pass through?

   • Box Z, the pancreas, which sends enzymes into box Y
   • Box W, the esophagus, which pushes food along
   • Box Y, the small intestine, which finishes digestion
   • Box X, the stomach, which holds food and churns it
3. 3.

   Chewing breaks a slice of bread into smaller pieces without changing its starch. Jun asks what kind of digestion chewing is.

   • Absorption, which moves nutrients into the blood
   • Mechanical digestion, which breaks food into smaller pieces
   • Mechanical digestion is the whole of digestion, so enzymes are not needed
   • Chemical digestion, which changes starch into sugar
4. 4.

   Saliva has an enzyme, amylase, that starts changing the starch in bread into sugar. Kira asks what kind of digestion that is.

   • Absorption, because the starch moves into the blood
   • Mechanical digestion, because it happens in the mouth
   • Chemical digestion, because an enzyme changes the starch
   • Not digestion, because chewing is the whole of digestion in the mouth
5. 5.

   In the stomach, muscles churn a mouthful of beans while acid and pepsin act on it. Luz asks which part is mechanical digestion.

   • No part, because the stomach holds food until it moves on
   • The acid, which helps pepsin start working
   • The pepsin, which breaks protein into smaller peptides
   • The churning, which mixes and breaks up the food
6. 6.

   Noah eats a bowl of beans. Pepsin in the stomach starts breaking down one nutrient in them. Which nutrient is it?

   • Fat, which pepsin breaks into fatty acids
   • Protein, which pepsin breaks into smaller peptides
   • Starch, since pepsin and amylase break down the same food
   • Sugar, which pepsin breaks into smaller sugars
7. 7.

   Pia eats a handful of nuts. Lipase, with help from bile, works on the oil in them. What does lipase make?

   • Fatty acids and monoglycerides, which are small enough to absorb
   • Bile, which is stored in the gallbladder
   • Amino acids, which are small enough to absorb
   • Sugars, which are small enough to absorb

8. Read this first

   Map (model, not to scale)

   One arrow runs from the digested sugars in the small intestine to a box marked ?. Other boxes on the map are the lacteal, the stomach lining and the large intestine.

9. 8.

   Ren reads the map. After an apple is digested, where do its sugars go first when they are absorbed?

   • Into the lacteals of the villi
   • Into the blood capillaries of the villi
   • Into the stomach lining, where most absorption happens
   • On to the large intestine, where most absorption happens

10. Use this

    Map (model, not to scale):

11. 9.

    Tala reads the map. What does the arrow from the large intestine to the circulatory system carry?

    • Pepsin, to finish digesting the protein
    • Water, taken back from the leftover material
    • Most of the sugars and amino acids from the meal
    • Bile, to finish digesting the fats
12. 10.

    Zee reads the map of where a meal's nutrients enter the blood. Which organ goes in the box marked ?

    • The esophagus, which carries food to the stomach
    • The large intestine, which receives the leftovers
    • The small intestine, which has villi
    • The stomach, which churns food and starts protein digestion