1. Decomposers Unit Lesson 3 Activity 2
Fungi Digestion and Biosynthesis
Image Credit: Craig Douglas, Michigan State University

2. How can a fungus digest food without a digestive system?
Image Credit: Craig Douglas, Michigan State University
Use Slide 2 of the Lesson 3.2 Modeling Digestion and Biosynthesis in Fungi Presentation to pose the question: How can a fungus digest food without a digestive system? Discuss students’ ideas about how this might happen.

3. Digesting OUTSIDE the Body
Fungi can break down polymers (large organic molecules) OUTSIDE their bodies
The cells in the hyphae send out digestive enzymes that break the polymer into monomers (small organic molecules)
The small monomers then can enter the cells of the hyphae and travel through the mycelium
Use Slide 3 to present the answer to this question: Fungi digest food outside their bodies by secreting digestive enzymes that break polymers down into monomers that can be absorbed by cells in the hyphae.

4. Decomposers use food in two ways
Materials for growth: Biosynthesis
Food
Digestion
Energy: Cellular respiration
Credit: Craig Douglas, Michigan State University
Use Slide 4 to remind students that decomposers use their food in two ways: materials for growth (biosynthesis) and energy (cellular respiration).

5. The Movement Question Where are atoms moving from?
Where are atoms moving to?
Image Credit: Craig Douglas, Michigan State University
Use Slides 5-8 to talk about the Location/Movement Question at the macroscopic and cellular level. Steps 2 through 7 of this Activity, modeling digestion and biosynthesis for fungi, are optional, depending on whether you have done this activity in the Animals or Plants Unit, and how well your students understood digestion and biosynthesis after those Units.

6. Which atoms and molecules move during digestion and biosynthesis?
amino acids
protein
Image Credit: Craig Douglas, Michigan State University
Use Slides 5-8 to talk about the Location/Movement Question at the macroscopic and cellular level. Steps 2 through 7 of this Activity, modeling digestion and biosynthesis for fungi, are optional, depending on whether you have done this activity in the Animals or Plants Unit, and how well your students understood digestion and biosynthesis after those Units.

7. How do amino acids and protein move during digestion?
Image Credit: Craig Douglas, Michigan State University
Use Slides 5-8 to talk about the Location/Movement Question at the macroscopic and cellular level. Steps 2 through 7 of this Activity, modeling digestion and biosynthesis for fungi, are optional, depending on whether you have done this activity in the Animals or Plants Unit, and how well your students understood digestion and biosynthesis after those Units.

8. What happens inside the fungus cell during biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use Slides 5-8 to talk about the Location/Movement Question at the macroscopic and cellular level. Steps 2 through 7 of this Activity, modeling digestion and biosynthesis for fungi, are optional, depending on whether you have done this activity in the Animals or Plants Unit, and how well your students understood digestion and biosynthesis after those Units.

9. Organic molecules LARGE = Polymer SMALL = Monomers STARCH
Image Credit: Craig Douglas, Michigan State University
Remind students about terminology for organic molecules by showing Slide 9 and explaining that polymers are large organic molecules, like starch, and monomers are small organic molecules, like glucose.
Tell students that “mono” means one, while “poly” means many.
STARCH
GLUCOSE (SUGAR)

10. Comparing molecules in dead stuff fungi eat
STARCH
GLUCOSE (SUGAR)
LIPIDS (FAT)
Image Credit: Craig Douglas, Michigan State University
Show Slide 10 to explain that carbohydrates, proteins, and fats all are found in food that fungi eat, which is dead stuff, like dead plants. Explain to students that all of these are composed mainly of carbon, hydrogen, and oxygen and are rich with chemical energy and have C-C and C-H bonds. Have students identify the atoms in each molecule.
PROTEIN
CELLULOSE (FIBER)

11. Monomers (small organic molecules)
Red paperclip = amino acid
Blue paperclip = glucose
Green paperclip = fatty acid
Purple paperclip = glycerol
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Show Slide, 11, and explain that students will use a single paperclip to represent a monomer using. Tell students that they will digest polymers into monomers and then rebuild monomers into polymers to represent how fungi eat and grow..
Give each pair of students a Decomposer 11 x 17 Poster. Give each pair of students at least 12 blue paperclips, 3 green paperclips, 1 purple paperclip, and 5 red paperclips.
Have each student in the pair be responsible for creating two of the four types of polymers.

12. Build food (dead stuff) molecules
Build a STARCH molecule by linking together 6 glucose monomers.
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Tell students that all food molecules go through this process, but just trace the location and movement of protein first, and put the other food molecules to the side of the poster. Follow the process for protein all the way to biosynthesis, then repeat using all of the food molecules (information for other molecules are in parentheses). At each step students will work with their paperclips and cards to mimic what is happening to the polymers through digestion, and place their molecules in the appropriate place on their poster using the information below.
Use Slides to assist students in building polymers out of their paper clips (food).

13. Build food (dead stuff) molecules
Build a FAT molecule by linking 3 fatty acid monomers to 1 glycerol molecule.
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Tell students that all food molecules go through this process, but just trace the location and movement of protein first, and put the other food molecules to the side of the poster. Follow the process for protein all the way to biosynthesis, then repeat using all of the food molecules (information for other molecules are in parentheses). At each step students will work with their paperclips and cards to mimic what is happening to the polymers through digestion, and place their molecules in the appropriate place on their poster using the information below.
Use Slides to assist students in building polymers out of their paper clips (food).

14. Build food (dead stuff) molecules
Build PROTEIN molecules by linking 5 amino acid monomers.
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Tell students that all food molecules go through this process, but just trace the location and movement of protein first, and put the other food molecules to the side of the poster. Follow the process for protein all the way to biosynthesis, then repeat using all of the food molecules (information for other molecules are in parentheses). At each step students will work with their paperclips and cards to mimic what is happening to the polymers through digestion, and place their molecules in the appropriate place on their poster using the information below.
Use Slides to assist students in building polymers out of their paper clips (food).

15. Build food (dead stuff) molecules
One type of carbohydrate is cellulose, also called fiber. Build a FIBER molecule by linking together 6 glucose monomers.
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Tell students that all food molecules go through this process, but just trace the location and movement of protein first, and put the other food molecules to the side of the poster. Follow the process for protein all the way to biosynthesis, then repeat using all of the food molecules (information for other molecules are in parentheses). At each step students will work with their paperclips and cards to mimic what is happening to the polymers through digestion, and place their molecules in the appropriate place on their poster using the information below.
Use Slides to assist students in building polymers out of their paper clips (food).

16. Food (dead stuff) polymers (large organic molecules)
LIPIDS (FAT) =link 3 fatty acid monomers to 1 glycerol
STARCH = 6 glucose monomers
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Tell students that all food molecules go through this process, but just trace the location and movement of protein first, and put the other food molecules to the side of the poster. Follow the process for protein all the way to biosynthesis, then repeat using all of the food molecules (information for other molecules are in parentheses). At each step students will work with their paperclips and cards to mimic what is happening to the polymers through digestion, and place their molecules in the appropriate place on their poster using the information below.
Use Slides to assist students in building polymers out of their paper clips (food).
PROTEIN = 5 amino acid monomers
CELLULOSE (FIBER) = 6 glucose monomers

17. Food molecules are dead things like stumps
Place large food molecules (dead stuff) here in trunk
Image Credit: Craig Douglas, Michigan State University
Use Slides to explain that fungi digestion of food (polymers) happens outside the fungi’s body. This is where the fungi use enzymes to break down the polymers into monomers (digestion).

18. Food is digested by fungal enzymes outside the fungi’s body
Get ready to digest the food molecules here
Image Credit: Craig Douglas, Michigan State University
Use Slides to explain that fungi digestion of food (polymers) happens outside the fungi’s body. This is where the fungi use enzymes to break down the polymers into monomers (digestion).

19. Breakdown Food Molecules (Digestion)
Let’s focus on what happens to PROTEIN in food for fungi (dead stuff).
(Put the other food molecules to the side of the poster for now.)
Digest PROTEIN molecules by breaking the protein into individual amino acids.
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Use Slides to assist students in breaking down the food molecules into monomers (digestion).
Chemical change

20. Breakdown Food Molecules (Digestion)
Digest STARCH molecules by breaking the starch into individual glucose monomers.
Chemical change
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Use Slides to assist students in breaking down the food molecules into monomers (digestion).

21. Breakdown Food Molecules (Digestion)
Digest FAT molecules by breaking the fat into individual fatty acid and glycerol monomers.
Chemical change
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Use Slides to assist students in breaking down the food molecules into monomers (digestion).

22. Breakdown Food Molecules (Digestion)
Digest FIBER molecules by breaking the cellulose into individual glucose monomers.
Chemical change
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Use Slides to assist students in breaking down the food molecules into monomers (digestion).

23. Small molecules are taken up and transported by fungal hyphae
Move the small molecules through the fungal hyphae
Image Credit: Craig Douglas, Michigan State University
Use Slides to show how monomers then move through the fungi after digestion occurs. Outside the fungi, the protein (and starch and fat) is completely broken down into monomers by enzymes that were excreted by the fungi. (In humans and other animals, fiber is not broken down. But fungi can digest fiber.) Explain to students that small molecules can move across cell membranes in fungi bodies, but large molecules cannot. Only small molecules move through the hyphae and mycelium. Have students break the protein into amino acids. (Break starch, fiber and fat into their monomers.) Take a moment to re-cap digestion of polymers into monomers at this point in the activity. Then pose the question: Once monomers are in the mycelium, where do they go? And Why? Elicit students’ ideas about cells and what cells might do with these basic materials.

24. Digested Monomers: where do they go?
glucose
fatty acid
Image Credit: Craig Douglas, Michigan State University
Use Slides to show how monomers then move through the fungi after digestion occurs. Outside the fungi, the protein (and starch and fat) is completely broken down into monomers by enzymes that were excreted by the fungi. (In humans and other animals, fiber is not broken down. But fungi can digest fiber.) Explain to students that small molecules can move across cell membranes in fungi bodies, but large molecules cannot. Only small molecules move through the hyphae and mycelium. Have students break the protein into amino acids. (Break starch, fiber and fat into their monomers.) Take a moment to re-cap digestion of polymers into monomers at this point in the activity. Then pose the question: Once monomers are in the mycelium, where do they go? And Why? Elicit students’ ideas about cells and what cells might do with these basic materials.
glycerol
amino acid

25. Build large molecules here
Biosynthesis is the process of small organic molecules becoming large organic molecules in all body parts
Build large molecules here
Image Credit: Craig Douglas, Michigan State University
Use Slide 25 to introduce the concept of biosynthesis. At each step have students work with their paperclips to mimic what is happening to the monomers after digestion, and place their molecules in the appropriate place on their poster. Remind students of the information they learned from mushroom nutritional labels. Tell students that mushrooms are primarily protein and fiber. When amino acids arrive at the cell they stay monomers until they reach the inside of the cells. They can only pass into a cell if they are still small. Remind students that fungi are made of polymers not monomers, so cells have to rebuild some of these monomers back into polymers in order to grow. If time allows make the connection to cell division at this time.

26. What’s in a fungi (mushroom)?
PROTEIN FIBER
Mushrooms
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips, food label): Michigan State University
Use the food label on Slide 26 to have students consider what a mushroom is made of.

27. Build a mushroom (Biosynthesis)
Build PROTEIN molecules by linking 5 amino acid monomers.
Chemical change
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Use Slides to discuss biosynthesis in fungi, having students build polymers out of their monomers.

28. Build mushroom (Biosynthesis)
Build FIBER molecules by linking 5 glucose monomers.
Chemical change
Image Credit (molecules): Craig Douglas, Michigan State University
Image Credit (paper clips): Michigan State University
Use Slides to discuss biosynthesis in fungi, having students build polymers out of their monomers.

29. What happens to food monomers that are not used in biosynthesis?
Image Credit: Craig Douglas, Michigan State University
Use Slides to pose the question: What happens to food monomers that are not used in biosynthesis? to remind students that some monomers are used for biosynthesis, and some are used for cellular respiration.

30. …put carbon dioxide from the cellular respiration now outside the mushroom
Image Credit: Craig Douglas, Michigan State University
Use Slides to pose the question: What happens to food monomers that are not used in biosynthesis? to remind students that some monomers are used for biosynthesis, and some are used for cellular respiration.

31. Identify chemical energy at an atomic molecular scale:
Which molecules have chemical energy?
Digested monomers in mushroom’s body:
Mushroom polymer molecules:
Fungi food, dead stuff (tree trunk):
Food
molecules:
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Example:
FAT
Example: AMINO ACID
Example: PROTEIN
Example:
CARBOHYDRATES

32. Identify where chemical energy is located (macroscopic scale):
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.

33. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Protein polymer (+ water)
Amino acid monomers
Reactants
Products

34. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Carbon atoms stay in organic molecules with high-energy bonds
Protein polymer (+ water)
Amino acid monomers
Reactants
Products

35. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Amino acid monomers
Protein polymer (+ water)
Reactants
Products

36. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Carbon atoms stay in organic molecules with high-energy bonds
Amino acid monomers
Protein polymer (+ water)
Reactants
Products

37. Digestion and biosynthesis of fats and carbohydrates (Optional)
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.

38. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Fat (+ water)
Fatty acids
+ glycerol
Reactants
Products

39. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Carbon atoms stay in organic molecules with high-energy bonds
Fat (+ water)
Fatty acids
+ glycerol
Reactants
Products

40. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Fatty acids + glycerol
Fat (+ water)
Reactants
Products

41. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Carbon atoms stay in organic molecules with high-energy bonds
Fatty acids + glycerol
Fat (+ water)
Reactants
Products

42. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Starch polymer (+ water)
Glucose monomers
Reactants
Products

43. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Carbon atoms stay in organic molecules with high-energy bonds
Starch polymer (+ water)
Glucose monomers
Reactants
Products 43

44. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Cellulose polymer (+ water)
Glucose monomers
Reactants
Products

45. What happens to carbon atoms and chemical energy in digestion?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Carbon atoms stay in organic molecules with high-energy bonds
Cellulose polymer (+ water)
Glucose monomers
Reactants
Products 45

46. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Glucose monomers
Starch polymer (+ water)
Reactants
Products

47. What happens to carbon atoms and chemical energy in biosynthesis?
Chemical change
Image Credit: Craig Douglas, Michigan State University
Use the animations on Slides 31 to 47 to show digestion and biosynthesis in fungi. Ask students to follow carbon atoms and chemical energy in both processes, and to remember “matter lasts forever” and “energy lasts forever.”
During the animations, focus on chemical energy. Remind students that molecules with C-C and C-H bonds have chemical energy that is useful to plants and animals.
Ask students to point out which molecules contain this useful chemical energy.
Carbon atoms stay in organic molecules with high-energy bonds
Glucose monomers
Starch polymer (+ water)
Reactants
Products

48. How do fungi digest dead plants?
What forms of energy are in the reactants?
What molecules are carbon atoms in before the change? What other molecules are involved?
Where are atoms moving from?
What forms of energy are in the products?
What molecules are carbon atoms in after the change? What other molecules are produced?
Where are atoms moving to?
Chemical change
Pass out the Lesson 3.2 Fungi Digestion and Biosynthesis Worksheet.
Have students complete the digestion process tool while showing Slide 48.
Have students complete the biosynthesis process tool while showing Slide 49.
Check to make sure that they are considering the rules at the bottom of the slides.
Remember: Atoms last forever and Energy lasts forever

49. How do fungi grow? What forms of energy are in the reactants?
What molecules are carbon atoms in before the change? What other molecules are involved?
Where are atoms moving from?
What forms of energy are in the products?
What molecules are carbon atoms in after the change? What other molecules are produced?
Where are atoms moving to?
Chemical change
Pass out the Lesson 3.2 Fungi Digestion and Biosynthesis Worksheet.
Have students complete the digestion process tool while showing Slide 48.
Have students complete the biosynthesis process tool while showing Slide 49.
Check to make sure that they are considering the rules at the bottom of the slides.
Remember: Atoms last forever and Energy lasts forever