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9th grade Digestion and how nutrients reach the blood worksheet

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Digestion and how nutrients reach the blood

Grade 9 Science Worksheet - Building Confidence

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Circle the best answer.

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

    • Box X, the stomach, which holds food and churns it
    • Box Y, the small intestine, which finishes digestion
    • Box Z, the pancreas, which sends enzymes into box Y
    • Box W, the esophagus, which pushes food along
  3. “Helper map (model, not to scale):” Esme reads the helper map. Which organ makes the bile, and which organ stores it?

    • The liver makes it, and the pancreas stores it
    • The liver makes it, and the gallbladder stores it
    • The pancreas makes it, and the gallbladder stores it
    • The gallbladder makes it, and the liver stores it
  4. Chewing breaks a slice of bread into smaller pieces without changing its starch. Jun asks what kind of digestion chewing is.

    • Chemical digestion, which changes starch into sugar
    • Mechanical digestion is the whole of digestion, so enzymes are not needed
    • Mechanical digestion, which breaks food into smaller pieces
    • Absorption, which moves nutrients into the blood
  5. Saliva has an enzyme, amylase, that starts changing the starch in bread into sugar. Kira asks what kind of digestion that is.

    • Mechanical digestion, because it happens in the mouth
    • Chemical digestion, because an enzyme changes the starch
    • Absorption, because the starch moves into the blood
    • Not digestion, because chewing is the whole of digestion in the mouth
  6. 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 pepsin, which breaks protein into smaller peptides
    • The acid, which helps pepsin start working
    • The churning, which mixes and breaks up the food
  7. Noah eats a bowl of beans. Pepsin in the stomach starts breaking down one nutrient in them. Which nutrient is it?

    • Protein, which pepsin breaks into smaller peptides
    • Starch, since pepsin and amylase break down the same food
    • Fat, which pepsin breaks into fatty acids
    • Sugar, which pepsin breaks into smaller sugars
  8. Pia eats a handful of nuts. Lipase, with help from bile, works on the oil in them. What does lipase make?

    • Bile, which is stored in the gallbladder
    • Amino acids, which are small enough to absorb
    • Sugars, which are small enough to absorb
    • Fatty acids and monoglycerides, which are small enough to absorb
  9. 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.

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

    • Into the stomach lining, where most absorption happens
    • Into the lacteals of the villi
    • On to the large intestine, where most absorption happens
    • Into the blood capillaries of the villi
  11. “Map (model, not to scale):” 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 small intestine, which has villi
    • The stomach, which churns food and starts protein digestion
    • The large intestine, which receives the leftovers
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9th grade Digestion and how nutrients reach the blood worksheet – printable
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About this worksheet

Digestion: how food reaches the blood. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can put the main organs of the digestive tract in order (mouth, esophagus, stomach, small intestine, large intestine) and say that the liver, gallbladder and pancreas are helpers: food does not pass through them, but bile (made by the liver, kept in the gallbladder) and enzymes (from the pancreas) are sent to the small intestine.
  • I can tell mechanical digestion (chewing and churning make smaller pieces without changing the molecules) from chemical digestion (enzymes break large molecules into small ones).
  • I can match an enzyme to the nutrient it breaks down: amylase to starch (salivary amylase in the mouth, pancreatic amylase in the small intestine), pepsin and trypsin to protein, lipase to fat, lactase to the milk sugar lactose; and say that bile is not an enzyme but breaks large fat globules into droplets so lipase reaches more fat.
  • I can say that an enzyme comes out of the reaction unchanged and can work again, and that each enzyme works on its own kind of molecule.
  • I can say that stomach acid stops salivary amylase, and that pancreatic juice raises the pH again in the small intestine.
  • I can say why the small intestine absorbs most nutrients (folds, villi and microvilli give it a huge surface area) and read a model of a folded strip.

Standard: HS-LS1-2

Words to know

digestion: Breaking food into pieces small enough to absorb, by mechanical and chemical means

mechanical digestion: Chewing and churning that make food pieces smaller without changing the molecules

chemical digestion: Enzymes breaking large food molecules into small ones

enzyme: A protein that speeds up a reaction and comes out unchanged

amylase: The enzyme that breaks starch into sugars, made in saliva and by the pancreas

pepsin: The stomach enzyme that starts breaking protein into smaller peptides

lipase: The enzyme that breaks fat into fatty acids and monoglycerides

bile: A fluid made in the liver that breaks large fat globules into small droplets

Common mistakes

Your child thought the stomach absorbs most of a meal's nutrients. The stomach mixes food and starts protein digestion, but the small intestine, with its villi, absorbs most nutrients. Ask your child which organ has villi.

Your child thought digestion is just chewing, or just breaking food into pieces. Chewing and churning are mechanical, and enzymes then break food into small molecules chemically. Ask your child what an enzyme does to the starch in bread.

Your child thought an enzyme is used up when it breaks down food. An enzyme comes out of the reaction unchanged and can work again, so it is the food that runs low. Ask your child what is left of the amylase after it splits starch.

Questions parents ask

What is the most common mistake with digestion and how nutrients reach the blood?

Your child thought the stomach absorbs most of a meal's nutrients. The stomach mixes food and starts protein digestion, but the small intestine, with its villi, absorbs most nutrients. Ask your child which organ has villi.

Are these 9th grade science worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

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