1. Carbon: Transformations in Matter and Energy
Environmental Literacy Project Michigan State University
Decomposers Unit Activity 5.3: Explaining How Fungi Grow: Digestion and Biosynthesis

2. Unit Map
You are here
Use the instructional model to show students where they are in the course of the unit.
Show slide 2 of the 5.3 Explaining How Fungi Grow: Digestion and Biosynthesis PPT.

3. Revisit your arguments
Think about what you know now that you didn’t know before. What have you learned?
Remind students of their unanswered questions.
Using slide 3 of the PPT have students revisit their arguments and unanswered questions from the Bread Molding Investigation by looking at 3.3 Evidence-Based Arguments for Bread Molding.
Remind students that after explaining cellular respiration in Lesson 4.2 there were still unanswered questions about how decomposers grow and where the glucose needed for cellular respiration comes from.
In today’s lesson, students will use what they learned in Lesson 5.1 (and 5.2) to explain how fungi get food to their body’s cells and how fungi use food for growth.

4. How do fungi use food as materials for growth?
Image Credit: Craig Douglas, Michigan State University
Have students review the process of digestion.
Use slides 4-5 of the 5.3 Explaining How Fungi Grow: Digestion and Biosynthesis PPT to guide students through a review of digestion.
Use Slide 4 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 5 to remind students what happens to the food that IS digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) that go into the hyphal cells.
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.
Note: If you only taught 5.1, you can use the posters to help students visualize the process, but do not need to focus on the names of the small organic molecules.

5. Step 1: Digestion Materials for growth: Biosynthesis Food Digestion
Energy: Cellular respiration
Credit: Craig Douglas, Michigan State University
Have students review the process of digestion.
Use slides 4-5 of the 5.3 Explaining How Fungi Grow: Digestion and Biosynthesis PPT to guide students through a review of digestion.
Use Slide 4 to review how decomposers use food to grow. Ask students for their ideas about what they remember from the previous activity.
Use slides 5 to remind students what happens to the food that IS digested: Large organic molecules (polymers) are divided into small organic molecules (monomers) that go into the hyphal cells.
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.
Note: If you only taught 5.1, you can use the posters to help students visualize the process, but do not need to focus on the names of the small organic molecules.

6. Constructing explanations
Consider the following as you construct your explanation:
Evidence from the investigation
What you learned from the molecular modeling or tracing activity
Three Questions Handout
Have students complete their Explanations Process Tool for Digestion.
Show slide 6 of the 5.3 Explaining How Fungi Grow: Digestion and Biosynthesis PPT. Give each student one copy of 5.3 Explanations Tool for Fungi Digestion.
Tell students that in this part of the investigation, they will combine everything they learned about how fungi get food to their body’s cells into an explanation.
Remind them to consider both their evidence from the investigation as well as what they learned in the molecular modeling (or tracing) activity to construct their explanations.
Give students about 10 minutes to complete the Explanations process tool.

7. Comparing Ideas with a Partner
Compare your explanations for each of the Three Questions.
How are they alike?
How are they different?
Check your explanation with the middle- and right-hand columns of the Three Questions handout.
Consider making revisions to your explanation based on your conversation with your partner.
Have students share explanations with each other.
Show slide 7 of the 5.3 Explaining How Fungi Grow: Digestion and Biosynthesis PPT. Divide students into pairs and have them compare explanations for the Three Questions and the final explanation on the process tool.
Have students use the Three Questions 11 x 17 Poster (or Handout) as a reference. Have students check their explanations with the middle and right-hand columns of the poster or handout to make sure they are following the “rules.”

8. The Matter Movement Question
Digestion:
The Matter Movement Question
How do molecules move to the location of the chemical change?
Image Credit: Craig Douglas, Michigan State University
Have students think about how digestion answers the Matter Movement question.
Use slides 8-14 in the PPT to have the students discuss what is happening to matter during digestion and to have them check their answers to the Matter Movement Question on their 5.3 Explanations Tool for Fungi Digestion.
Show students slides 8-10 to have them think about where atoms are moving from and moving to during digestion.
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slides. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
How do molecules move away from the location of the chemical change?

9. 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 how digestion answers the Matter Movement question.
Use slides 8-14 in the PPT to have the students discuss what is happening to matter during digestion and to have them check their answers to the Matter Movement Question on their 5.3 Explanations Tool for Fungi Digestion.
Show students slides 8-10 to have them think about where atoms are moving from and moving to during digestion.
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slides. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response

10. How do small and large organic molecules 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 how digestion answers the Matter Movement question.
Use slides 8-14 in the PPT to have the students discuss what is happening to matter during digestion and to have them check their answers to the Matter Movement Question on their 5.3 Explanations Tool for Fungi Digestion.
Show students slides 8-10 to have them think about where atoms are moving from and moving to during digestion.
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slides. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

11. Matter Movement Do you have:
a label showing large organic molecules or polymers (carbohydrates, proteins, fat/lipids) in the detritus?
Large Organic Molecules
Image Credit: Craig Douglas, Michigan State University
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slides. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

12. Matter Movement Do you have:
a label showing small organic molecules in the detritus and an arrow showing them entering the hyphal cell?
Large Organic Molecules
Image Credit: Craig Douglas, Michigan State University
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slides. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
Small Organic Molecules

13. Matter Movement Do you have:
an arrow showing small organic molecules moving through the hyphal cells?
Large Organic Molecules
Image Credit: Craig Douglas, Michigan State University
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slides. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
Small Organic Molecules

14. Matter Movement Do you have:
an arrow showing small organic molecules moving through the fungus?
Large Organic Molecules
Image Credit: Craig Douglas, Michigan State University
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slides. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
Small Organic Molecules

15. The Matter Change Question
Digestion:
The Matter Change Question
What molecules are carbon atoms in before and after the chemical change?
What other molecules are involved?
Image Credit: Craig Douglas, Michigan State University
Have students think about how digestion also answers the Matter Change Question.
Show slide 15 to begin discussion the Matter Change Question.
Display slides to have students compare their answers to the Matter Change Question on the 5.3 Explanations Tool for Fungi Digestion with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
Note: fungi produce and release molecules (enzymes) that can break large organic molecules up into small organic molecules.

16. Matter Change
Name the chemical change that a fungus uses to break down food: Digestion
Have students think about how digestion also answers the Matter Change Question.
Show slide 15 to begin discussion the Matter Change Question.
Display slides to have students compare their answers to the Matter Change Question on the 5.3 Explanations Tool for Fungi Digestion with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

17. Matter Change
What molecules are carbon atoms in before the chemical change? Large organic molecules (or polymers: carbohydrates, fats/lipids, and proteins) What other molecules are needed? (Water)
What molecules are carbon atoms in after the chemical change? Small organic molecules (or monomers: amino acids, sugars, and fatty acids) What other molecules are produced? None
Chemical Change
Have students think about how digestion also answers the Matter Change Question.
Show slide 15 to begin discussion the Matter Change Question.
Display slides to have students compare their answers to the Matter Change Question on the 5.3 Explanations Tool for Fungi Digestion with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

18. Digestion: The Energy Change Question
What forms of energy are involved?
What energy transformations take place during the chemical change?
Image Credit: Craig Douglas, Michigan State University
Discuss how digestion helps to answer Energy Change Question.
Display slide 18 to begin discussing the Energy Change Question.
Display slide 19 to have students compares their answers to the Energy Change Question on the 5.3 Explanations Tool for Fungi Digestion with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

19. Energy Change
What forms of energy go into this chemical change? Chemical Energy
What forms of energy come out of this chemical change? Chemical Energy
Energy Transformation
Discuss how digestion helps to answer Energy Change Question.
Display slide 18 to begin discussing the Energy Change Question.
Display slide 19 to have students compares their answers to the Energy Change Question on the 5.3 Explanations Tool for Fungi Digestion with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

20. Telling the Whole Story
Question: How does a fungus get small organic molecules to its cells?
Does your story include these parts?
Matter movement: Large organic molecules make up the detritus outside of the fungus.
Matter change: The large organic molecules of the detritus are broken into small organic molecules by enzymes released by the fungus.
Energy change: The chemical energy of the C-C and C-H bonds in the large organic molecules remains in the C-C and C-H bonds of small organic molecules.
Matter movement: The small organic molecules move into the fungus’ hyphal cells. These molecules go to all parts of the fungus to be used for cellular respiration and biosynthesis.
Have students review their full explanations.
Display slide 20 of the PPT for the full story of digestion. Have students check that their story includes each of the parts (matter movement, matter change, energy change, and matter movement).
If students don’t have all four parts in their explanation, instruct them to add to their explanation using a different colored writing utensil.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

21. Step 2: Biosynthesis Materials for growth: Biosynthesis Food Digestion
Energy: Cellular respiration
Credit: Craig Douglas, Michigan State University
Discuss what happens to the small organic molecules after digestion.
Show slide 21 of the PPT. Remind students that the products of digestion (small organic molecules or monomers) can be used by cells for either growth or energy.
Allows students to talk through the process of cellular respiration as a review.

22. Constructing explanations
Consider the following as you construct your explanation:
Evidence from the investigation
What you learned from the molecular modeling or tracing activity
Three Questions Handout
Have students complete their Explanations Process Tool for Biosynthesis.
Show slide 22 of the 5.3 Explaining How Fungi Grow: Digestion and Biosynthesis PPT. Give each student one copy of 5.3 Explanations Tool for Fungi Biosynthesis.
Tell students that in this part of the investigation, they will combine everything they learned about how decomposers use food to grow into an explanation.
Remind them to consider both their evidence from the investigation as well as what they learned in the molecular modeling (or tracing) activity to construct their explanations.
Give students about 10 minutes to complete the Explanations process tool.

23. Comparing Ideas with a Partner
Compare your explanations for each of the Three Questions.
How are they alike?
How are they different?
Check your explanation with the middle- and right-hand columns of the Three Questions handout.
Consider making revisions to your explanation based on your conversation with your partner.
Have students share explanations with each other.
Show slide 23 of the 5.3 Explaining How Fungi Grow: Digestion and Biosynthesis PPT. Divide students into pairs and have them compare explanations for the Three Questions and the final explanation on the process tool.
Have students use the Three Questions 11 x 17 Poster (or Handout) as a reference. Have students check their explanations with the middle and right-hand columns of the poster or handout to make sure they are following the “rules.”

24. The Matter Movement Question
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 how biosynthesis answers the Matter Movement question.
Use slides in the PPT to have the students discuss what is happening to matter during biosynthesis and to have them check their answers to the Matter Movement Question on their 5.3 Explanations Tool for Fungi Biosynthesis.
Show students slide 24 to have them think about where atoms are moving from and moving to during biosynthesis.
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slide. Students only need to have arrows showing the movement of molecules into and out of the cell. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
How do fungal cells use small organic molecules to grow and divide?

25. Matter Movement Do you have:
an arrow showing small organic molecules or monomers going into the fungal cell?
Small Organic Molecules
Image Credit: Craig Douglas, Michigan State University
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slide. Students only need to have arrows showing the movement of molecules into and out of the cell. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

26. Matter Movement Do you have:
large organic molecules (or polymers) staying in the fungal cell?
Small Organic Molecules
Large organic molecules
Image Credit: Craig Douglas, Michigan State University
Display slides to have students compare their answers to the Matter Movement Question with the answers on the slide. Students only need to have arrows showing the movement of molecules into and out of the cell. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

27. The Carbon and Energy Questions:
What happens to small organic molecules during biosynthesis?
The Matter Change Question
Chemical change
Image Credit: Craig Douglas, Michigan State University
Have students think about how biosynthesis answers the Matter Change Question.
Show slide 27 to begin discussing the Matter Change Question.
Display slides to have students compare their answers to the Matter Change Question on the 5.3 Explanations Tool for Fungi Biosynthesis with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
Refer to the Digestion and Biosynthesis 11 x 17 Posters in your classroom to help students visualize the biosynthesis of monomers to polymers.
Small organic molecules (monomers) go into cells, but don’t come out. What happens inside the cells?

28. Matter Change
Name the chemical change that fungal cells use to build large organic molecules: Biosynthesis
Display slides to have students compare their answers to the Matter Change Question on the 5.3 Explanations Tool for Fungi Biosynthesis with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
Refer to the Digestion and Biosynthesis 11 x 17 Posters in your classroom to help students visualize the biosynthesis of monomers to polymers.

29. Matter Change
What molecules are carbon atoms in before the chemical change? Small organic molecules (or monomers such as amino acids, sugars, and fatty acids) What other molecules are needed? None
What molecules are carbon atoms in after the chemical change? Large organic molecules (or fats/lipids, and proteins) What other molecules are produced? Water
Chemical Change
Display slides to have students compare their answers to the Matter Change Question on the 5.3 Explanations Tool for Fungi Biosynthesis with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.
Refer to the Digestion and Biosynthesis 11 x 17 Posters in your classroom to help students visualize the biosynthesis of monomers to polymers.

30. Energy Change
What forms of energy go into this chemical change? Chemical Energy
What forms of energy come out of this chemical change? Chemical Energy
Energy Transformation
Discuss how biosynthesis helps answer the Energy Change questions.
Display slide 30 to have students compare their answers to the Energy Change Question on the 5.3 Explanations Tool for Fungi Biosynthesis with the answers on the slide. Have students use a different colored writing utensil to make any needed changes to their answers. Allow students to ask questions if they do not understand why their ideas are incorrect.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

31. Telling the Whole Story
Question: How does a cell in the stem of a fungus use food to grow and divide?
Does your story include these parts?
Matter movement: Small organic molecules (or monomers, such as amino acids, sugars, fatty acids, and glycerol) enter the fungal cell.
Matter change: The small organic molecules are combined to make large organic molecules (or polymers, such as carbohydrates, fats/lipids, and proteins).
Energy change: The chemical energy stored in the C-C and C-H bonds in the small organic molecules (monomers) stays in these bonds when they are combined into large organic molecules (polymers).
Matter movement: The cell grows bigger and may eventually divide as more large organic molecules (polymers) are made.
Have students review their full explanations.
Display slide 31 of the PPT for the full story of biosynthesis. Have students check that their story includes each of the parts (matter movement, matter change, energy change, and matter movement).
If students don’t have all four parts in their explanation, instruct them to add to their explanation using a different colored writing utensil.
If students have model explanations to share, display student work and discuss. If students have common areas of weakness in their explanations, ask for a volunteer to share, display student work, and discuss ways of strengthening the response.

32. Discuss with a partner
Have students discuss with a partner how digestion and biosynthesis work at the macroscopic scale by referring to the decomposer poster.
Show slide 32. Have students look at the Decomposer 11 x 17 Poster and discuss with a partner the parts of a fungus involved in digestion and biosynthesis on a macroscopic scale.
Tell students that digestion occurs outside the hyphal cells and that all parts (all cells) of a fungus’ body undergo biosynthesis.