1. Carbon: Transformations in Matter and Energy
Environmental Literacy Project Michigan State University
Decomposers Unit Activity 3.3a: Explaining Decomposer Digestion and Biosynthesis
Image Credit: Craig Douglas, Michigan State University

2. How do fungi use food as materials for growth?
Image Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

3. Step 1: Digestion Materials for growth: Biosynthesis Food Digestion
Energy: Cellular respiration
Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

4. Answering the Three Questions for Digestion
Image Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

5. The Movement Question Where are atoms moving from?
Where are atoms moving to?
Image Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

6. Which atoms and molecules move during fungal digestion?
Small organic molecules (monomers: amino acids, glucose, fatty acids, glycerol)
Large organic molecules (polymers: proteins, carbs, fats)
Image Credits: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

7. How do amino acids and protein move during fungal digestion?
Small organic molecules (monomers: amino acids, glucose, fatty acids, glycerol)
Large organic molecules (polymers: proteins, carbs, fats)
Image Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

8. Decomposers don’t digest everything
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

9. Digestion: The Carbon and Energy Questions
What is happening to carbon atoms?
What is happening to chemical energy?
Image Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.

10. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.
Monomers
like amino acids
Polymer like protein (+ water)
Reactants
Products

11. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Have students think about the Three Questions for digestion.
Use slides 2-11 of the 3.3a Explaining Digestion and Biosynthesis PPT to guide students through a discussion of digestion and the Three Questions. (Note that the PPT models digestion for protein molecules only. Carbohydrates and fats are also divided into monomers during digestion).
Use Slide 2 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 3-7 to show students what happens to the food that is digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) and move to all the other parts of the fungal body.
Use slide 8 to remind students that fungi do not digest all of dead animals and plants, some of that organic materials stays in the soil.
Use slides 9-11 to discuss the answers to the Carbon Question and the Energy Question for digestion: Digestion divides large organic molecules (polymers) into smaller organic molecules (monomers).
Discuss how food is made mostly of water and large organic molecules, but only small organic molecules (amino acids, sugars, fatty acids) are absorbed by hyphal cells and travel through the fungal body.
Display the following posters in your classroom to help students visualize the digestion of polymers to monomers.
Carbohydrates: Use the Digestion and Biosynthesis of Carbohydrates 11 x 17 Poster to offer students a visualization of how polymers like starch (which is a type of carbohydrate) are broken apart into monomers like glucose.
Fat: Use the Digestion and Biosynthesis of Fat 11 x 17 Poster to offer students a visualization of how polymers like fat are broken apart into monomers like fatty acids and glycerol.
Proteins: Use the Digestion and Biosynthesis of Protein 11 x 17 Poster to offer students a visualization of how polymers like proteins are broken down into amino acids.
Carbon atoms stay in organic molecules with high-energy bonds
Polymer like protein
(+ water)
Monomers
like amino acids
Reactants
Products

12. Step 2: Biosynthesis Materials for growth: Biosynthesis Food Digestion
Energy: Cellular respiration
Credit: Craig Douglas, Michigan State University
Have students answer the Three Questions for biosynthesis.
Use slides to transition from digestion to biosynthesis. (Note that the PPT models biosynthesis using protein molecules. Fungal cells also build carbohydrates from sugars, but they do not biosynthesize fats.)
Use slides to discuss the Movement Question for biosynthesis. Food is made mostly of water and large organic molecules, but only small organic molecules (amino acids and sugars are absorbed by hyphal cells and travel through the fungal body. Small organic molecules such as amino acids and sugars go into cells, but they don’t come out. This is how cells grow.
Use slides to discuss the Carbon Question and the Energy Question for biosynthesis: Biosynthesis builds large organic molecules (polymers) out of smaller organic molecules (monomers).
Refer to the Digestion and Biosynthesis posters in your classroom to help students visualize the biosynthesis of monomers to polymers. Remember: fungi do not biosynthesize fat (which is why there is no fat on the mushroom food label).

13. Answering the Three Questions for Biosynthesis
Image Credit: Craig Douglas, Michigan State University
Have students answer the Three Questions for biosynthesis.
Use slides to transition from digestion to biosynthesis. (Note that the PPT models biosynthesis using protein molecules. Fungal cells also build carbohydrates from sugars, but they do not biosynthesize fats.)
Use slides to discuss the Movement Question for biosynthesis. Food is made mostly of water and large organic molecules, but only small organic molecules (amino acids and sugars are absorbed by hyphal cells and travel through the fungal body. Small organic molecules such as amino acids and sugars go into cells, but they don’t come out. This is how cells grow.
Use slides to discuss the Carbon Question and the Energy Question for biosynthesis: Biosynthesis builds large organic molecules (polymers) out of smaller organic molecules (monomers).
Refer to the Digestion and Biosynthesis posters in your classroom to help students visualize the biosynthesis of monomers to polymers. Remember: fungi do not biosynthesize fat (which is why there is no fat on the mushroom food label).

14. The Movement Question: How do animal cells
use small organic molecules to grow and divide?
Small organic molecules (monomers: amino acids, glucose, fatty acids, glycerol)
Large organic molecules (polymers: proteins, carbs, fats)
Image Credit: Craig Douglas, Michigan State University
Have students answer the Three Questions for biosynthesis.
Use slides to transition from digestion to biosynthesis. (Note that the PPT models biosynthesis using protein molecules. Fungal cells also build carbohydrates from sugars, but they do not biosynthesize fats.)
Use slides to discuss the Movement Question for biosynthesis. Food is made mostly of water and large organic molecules, but only small organic molecules (amino acids and sugars are absorbed by hyphal cells and travel through the fungal body. Small organic molecules such as amino acids and sugars go into cells, but they don’t come out. This is how cells grow.
Use slides to discuss the Carbon Question and the Energy Question for biosynthesis: Biosynthesis builds large organic molecules (polymers) out of smaller organic molecules (monomers).
Refer to the Digestion and Biosynthesis posters in your classroom to help students visualize the biosynthesis of monomers to polymers. Remember: fungi do not biosynthesize fat (which is why there is no fat on the mushroom food label).

15. The Carbon and Energy Questions: What happens to carbon atoms and chemical energy during biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Have students answer the Three Questions for biosynthesis.
Use slides to transition from digestion to biosynthesis. (Note that the PPT models biosynthesis using protein molecules. Fungal cells also build carbohydrates from sugars, but they do not biosynthesize fats.)
Use slides to discuss the Movement Question for biosynthesis. Food is made mostly of water and large organic molecules, but only small organic molecules (amino acids and sugars are absorbed by hyphal cells and travel through the fungal body. Small organic molecules such as amino acids and sugars go into cells, but they don’t come out. This is how cells grow.
Use slides to discuss the Carbon Question and the Energy Question for biosynthesis: Biosynthesis builds large organic molecules (polymers) out of smaller organic molecules (monomers).
Refer to the Digestion and Biosynthesis posters in your classroom to help students visualize the biosynthesis of monomers to polymers. Remember: fungi do not biosynthesize fat (which is why there is no fat on the mushroom food label).
Small organic molecules go into cells, but don’t come out. What happens inside the cells?

16. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Have students answer the Three Questions for biosynthesis.
Use slides to transition from digestion to biosynthesis. (Note that the PPT models biosynthesis using protein molecules. Fungal cells also build carbohydrates from sugars, but they do not biosynthesize fats.)
Use slides to discuss the Movement Question for biosynthesis. Food is made mostly of water and large organic molecules, but only small organic molecules (amino acids and sugars are absorbed by hyphal cells and travel through the fungal body. Small organic molecules such as amino acids and sugars go into cells, but they don’t come out. This is how cells grow.
Use slides to discuss the Carbon Question and the Energy Question for biosynthesis: Biosynthesis builds large organic molecules (polymers) out of smaller organic molecules (monomers).
Refer to the Digestion and Biosynthesis posters in your classroom to help students visualize the biosynthesis of monomers to polymers. Remember: fungi do not biosynthesize fat (which is why there is no fat on the mushroom food label).
Monomers
like amino acids
Polymers like proteins
(+ water)
Reactants
Products

17. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Have students answer the Three Questions for biosynthesis.
Use slides to transition from digestion to biosynthesis. (Note that the PPT models biosynthesis using protein molecules. Fungal cells also build carbohydrates from sugars, but they do not biosynthesize fats.)
Use slides to discuss the Movement Question for biosynthesis. Food is made mostly of water and large organic molecules, but only small organic molecules (amino acids and sugars are absorbed by hyphal cells and travel through the fungal body. Small organic molecules such as amino acids and sugars go into cells, but they don’t come out. This is how cells grow.
Use slides to discuss the Carbon Question and the Energy Question for biosynthesis: Biosynthesis builds large organic molecules (polymers) out of smaller organic molecules (monomers).
Refer to the Digestion and Biosynthesis posters in your classroom to help students visualize the biosynthesis of monomers to polymers. Remember: fungi do not biosynthesize fat (which is why there is no fat on the mushroom food label).
Carbon atoms stay in organic molecules with high-energy bonds
Monomers
like amino acids
Polymer like protein
(+ water)
Reactants
Products