Digestion Expedition Lesson Plan Digestion Expedition
Teacher Facilitation Guide
Subject: Biology / Life Science
Duration: 60-90 Minutes
Topic: Digestive System & Enzymes
Learning Objectives
Trace the path of food through the alimentary canal.
Distinguish between mechanical and chemical digestion.
Explain enzyme specificity and identify key enzymes (Amylase, Pepsin, Lipase).
Relate organ structure to its digestive function.
Materials Needed
Gut Tour Guided Notes
Enzyme Action Worksheet
Crackers (for "The Cracker Challenge")
System Sprint Quiz
Instructional Flow
The Hook: The 60-Second Cracker (5-10 mins)
Give each student a plain saltine cracker. Instruct them to hold it in their mouth without chewing for 60 seconds. Ask: "Does the taste change?" (It should start tasting sweet as salivary amylase breaks down starch into glucose). This introduces chemical digestion immediately.
Guided Notes & Mini-Lecture (20 mins)
Use the Gut Tour Guided Notes . Focus on the distinction between the alimentary canal (the "tube") and accessory organs (Liver, Pancreas, Gallbladder). Emphasize that food never enters the accessory organs.
Key Discussion Point: Surface area! Explain how the small intestine's villi maximize nutrient absorption like a high-pile carpet.
Group Activity: The Enzyme Lock-and-Key (20 mins)
Students work in pairs using the Enzyme Action Worksheet . They must "match" the substrate to the correct enzyme based on shape (specificity). Use the visual of a lock and key to explain why Pepsin won't break down fats.
Synthesis & Review (10 mins)
Review the Digestion Pro Study Guide . Use a "Quick-Fire" round: name an organ, and students shout out "Mechanical," "Chemical," or "Both."
Pro-Tips & Differentiation
For Emerging Learners
Provide a word bank for the Guided Notes. Use a physical tube (like a garden hose) to visualize the 30-foot length of the digestive system.
For Advanced Learners
Challenge them to explain why the stomach doesn't digest itself (mucus lining + inactive pepsinogen) and how pH affects enzyme activity.
Gut Tour Guided Notes Gut Tour: Guided Notes
Digestive System Review Expedition
Name:
Date:
The Mission
The digestive system converts food into ____________________ that can be absorbed and used by the body's cells.
Mechanical vs. Chemical Digestion
MECHANICAL
Physical breakdown of food into smaller pieces to increase _________________ ______________ .
Example: Teeth chewing, stomach churning.
CHEMICAL
Breaking down food into simpler molecules using _________________ and acids.
Example: Saliva breaking down starch.
The Path of Food
1. MOUTH
Digestion begins! Mechanical: teeth/tongue. Chemical: salivary ______________ (breaks starches).
2. ESOPHAGUS
Muscular tube that pushes food to the stomach using wave-like motions called ____________________ .
3. STOMACH
A muscular sac. Mechanical: Churning. Chemical: Hydrochloric acid + _________________ (breaks protein).
4. SMALL INT.
Most digestion and ____________________ occurs here. Lined with finger-like villi.
5. LARGE INT.
Removes _________________ from undigested waste before it leaves the body.
The Accessory Squad
Food never enters these organs, but they produce vital chemicals!
LIVER
Produces BILE , which acts like soap to break up (emulsify) _____________ .
GALLBLADDER
Stores the _________________ until it is needed in the small intestine.
PANCREAS
Produces "Pancreatic Juice" containing enzymes that break down EVERY type of nutrient.
Self-Check: Can you trace the path of a hamburger from the first bite to the exit? Highlight any organs where chemical digestion of PROTEIN happens.
Enzyme Action Worksheet Enzyme Action: Lock & Key
Specificity, Substrates, and Chemical Breakdowns
Worksheet #2
I. The Perfect Fit
Match the term to its correct definition by writing the letter in the space provided.
1. Enzyme
2. Substrate
3. Active Site
4. Products
5. Denature
A. The specific location on an enzyme where the substrate binds.
B. To change the shape of an enzyme (due to heat/pH), making it useless.
C. A biological catalyst that speeds up chemical reactions.
D. The molecules that result after the enzyme finishes the reaction.
E. The specific reactant that an enzyme acts upon.
II. Enzyme Specialized Task Force
Complete the chart below to identify where these enzymes work and what they do.
Enzyme Found In... Breaks Down... Amylase Mouth / Small Int. Pepsin Stomach Lipase Small Intestine Protease Small Intestine
Think & Solve:
"A person has a condition where their stomach acid is too weak. Which enzyme would be most affected, and which nutrient would they have trouble digesting?"
III. Label the Enzyme Reaction
Active Complex
Use these words: Enzyme, Substrate, Products, Active Site
Digestion Pro Study Guide Digestion Study Pro
Essential Concept Summary & Key Terms
The Glossary of Digestion
Alimentary Canal: The continuous tube food travels through from mouth to anus.
Peristalsis: Involuntary muscular waves that push food through the tract.
Chyme: The thin, watery liquid food becomes after being processed by the stomach.
Villi: Finger-like projections in the small intestine that increase surface area.
Bile: Greenish fluid produced by the liver that breaks down (emulsifies) fats.
Enzyme: A protein that speeds up chemical reactions without being consumed.
Mechanical vs. Chemical Breakdown
Mechanical
Physical tearing and crushing. Happens in Mouth and Stomach.
Chemical
Molecules broken into units (monomers). Requires enzymes and acids.
Enzyme "Cheat Sheet"
Nutrient Enzyme Location Result (Monomer) Carbs / Starch Amylase Mouth / Small Int. Simple Sugars Protein Pepsin / Protease Stomach / Small Int. Amino Acids Fats / Lipids Lipase Small Intestine Fatty Acids
The Route Recap
Mouth Esophagus Stomach Small Intestine Large Intestine Exit
Pro Tip for the Quiz:
Absorption mostly happens in the Small Intestine . The Large Intestine is mainly for water and solid waste! Accessory organs like the Pancreas and Liver send "help" to the Small Intestine but never touch the food themselves.
System Sprint Quiz System Sprint Quiz
Assessment: Digestion & Enzymes
Student Name:
Score: / 20
I. Multiple Choice (10 pts)
1. Which organ is the primary site for nutrient absorption into the bloodstream?
A) Stomach
B) Large Intestine
C) Small Intestine
D) Esophagus
2. What is the role of bile in the digestive process?
A) To digest carbohydrates in the mouth.
B) To emulsify fats into smaller droplets for enzymes to work.
C) To lower the pH of the stomach to activate pepsin.
D) To absorb water from undigested waste.
3. Enzyme specificity is best described by which of the following models?
A) Hammer and Nail
B) Lock and Key
C) Hand and Glove
D) Needle and Thread
4. Which of these is an example of mechanical digestion?
A) Amylase breaking down starch into glucose.
B) Hydrochloric acid denaturing proteins.
C) Churning of the stomach muscles to mix food.
D) Protease breaking amino acid bonds.
5. What happens to an enzyme if the temperature or pH becomes too extreme?
A) It works faster
B) It denatures (loses shape)
C) It multiplies
D) It turns into a substrate
II. Labeling & Identification (5 pts)
A
B
C
D
E
Match the letter to the organ:
Small Intestine
Mouth
Stomach
Esophagus
Large Intestine
III. Short Connection (5 pts)
Why is it important that the small intestine is roughly 20 feet long and covered in villi? Explain using the concept of surface area.
Review Master Answer Key Review Master: Answer Key
Teacher Reference Only
Gut Tour Guided Notes Key
Mission: Nutrients
Mech vs Chem: Surface area / Enzymes
Mouth: Amylase
Esophagus: Peristalsis
Stomach: Pepsin
Small Int.: Absorption
Large Int.: Water
Accessory: Bile / Gallbladder
Enzyme Action Worksheet Key
Matching:
1. C | 2. E | 3. A | 4. D | 5. B
Breaks Down Chart:
Amylase: Carbohydrates / Starch
Pepsin: Proteins
Lipase: Fats (Lipids)
Protease: Proteins
Think & Solve: Pepsin would be affected; protein digestion would be impaired because pepsin needs an acidic environment to work.
System Sprint Quiz Key
Multiple Choice:
1. C | 2. B | 3. B | 4. C | 5. B
Labeling Match:
Mouth: A
Esophagus: B
Stomach: C
Small Intestine: E
Large Intestine: D
Short Response Rubric:
- Full Credit: Mentions that 20 feet + villi provide massive surface area , which allows more nutrients to come into contact with the intestinal walls for faster/more efficient absorption .Partial Credit: Mentions absorption but misses the connection to surface area, or vice versa.
Tip: Use the "Cracker Challenge" as an anchor throughout the lesson to remind students of salivary amylase.
Digestion Discovery Slides Digestion Discovery
The Expedition Through the Human Gut
Breaking It Down
Mechanical
Physical changes to food to increase surface area .
Chewing in the mouth
Churning in the stomach
Chemical
Using enzymes and acids to break bonds and create new, simpler molecules.
Saliva breaking starch
Pepsin breaking protein
"The Lock and Key Model"
Substrate
(The Food)
Enzyme
(The Tool)
Enzymes are Specific.
The Support Squad
Food never enters these organs, but they are essential!
Liver
Creates Bile to break down fats.
Gallbladder
Stores the bile until the small intestine needs it.
Pancreas
Produces enzymes for all types of nutrients.
Stomach Starter Warm Up Stomach Starter
Daily Warm-Up: Thinking about Digestion
Name:
Date:
1. The Cracker Observation
If you hold a plain saltine cracker in your mouth for 60 seconds without chewing, it begins to taste sweet. Why do you think this happens?
2. Digestion Duel
List one example of mechanical digestion and one example of chemical digestion that happens in your body right now.
Mechanical Example:
Chemical Example:
3. Path Prediction
Place these organs in the correct order that food travels through them:
Stomach Mouth Small Intestine Esophagus
Digestive Debrief Exit Ticket Digestive Debrief
Exit Ticket
Name:
1. What is the main job of enzymes in digestion?
2. Explain the "Lock and Key" model in your own words.
3. Circle the organ where most nutrient absorption happens:
Stomach Small Intestine Large Intestine
Expedition Complete
Digestive Debrief
Exit Ticket
Name:
1. What is the main job of enzymes in digestion?
2. Explain the "Lock and Key" model in your own words.
3. Circle the organ where most nutrient absorption happens:
Stomach Small Intestine Large Intestine
Expedition Complete
Gut Tour Guided Notes Modified Gut Tour: Guided Notes
Level 1: The Body's Food Factory
Name:
Word Bank
Water Small Intestine Energy Enzymes Esophagus Stomach Surface Area
Why we digest:
The digestive system breaks food into tiny pieces so our body can get ____________________ .
Mechanical vs. Chemical
Mechanical: Breaking food into smaller bits to increase _________________ ______________ .
Chemical: Using "chemical scissors" called _________________ to break food down.
The Food Path
1. MOUTH
Digestion starts here! Teeth chew the food.
2. ___________
A tube that carries food down to the stomach.
3. ___________
A muscular bag that mashes food and uses acid.
4. ___________
Where the body absorbs nutrients into the blood.
5. LARGE INT.
Soaks up extra _________________ from the waste.
The Helpers (Accessory Organs)
LIVER: Makes a green liquid called BILE to help break down fats.
PANCREAS: Makes a special juice that contains many enzymes.
Enzyme Basics Worksheet Modified Enzyme Basics: Chemical Scissors
Level 1: Understanding how enzymes work.
1. Match the Picture
Draw a line from the word to its meaning.
ENZYME
SUBSTRATE
SPECIFIC
The "food" or molecule being broken down.
The helper that breaks things down fast.
Only fits one special shape (like a key).
2. Enzyme True or False
Enzymes break food into smaller pieces.
TRUE FALSE
One enzyme can break down ALL types of food.
TRUE FALSE
Heat can change an enzyme's shape so it stops working.
TRUE FALSE
3. Which enzyme?
Look at the chart and answer the question.
AMYLASE
Breaks Starch (Carbs)
PEPSIN
Breaks Protein
LIPASE
Breaks Fat
Question: You ate a piece of chicken (which is mostly protein). Which enzyme will your stomach use to break it down?
System Sprint Quiz Modified System Sprint Quiz
Level 1: Digestion Basics
Name:
1. Circle the correct answer:
A. Where does most absorption of food happen?
Mouth
Small Intestine
Liver
B. Which organ creates Bile to help break down fats?
Liver
Stomach
Heart
C. What is mechanical digestion?
Using chemicals to break food.
Physical crushing and mashing of food.
2. Label the Path of Food
Word Bank: Stomach | Mouth | Esophagus | Large Intestine | Small Intestine
1. Where food enters: ___________________________
2. The tube to the stomach: ______________________
3. The muscular bag: ____________________________
4. Where we absorb nutrients: ___________________
5. Where we absorb water: _______________________
3. Draw the "Lock and Key"
In the box below, draw a quick picture showing how an enzyme fits into its substrate like a key in a lock.
(Draw your picture here)
Digestion Discovery Slides Modified Digestion Basics
Level 1: How We Break Down Food
Two Ways to Break Food
1. Crushing
Called Mechanical digestion.
Like chewing or a blender mashing food.
2. Melting
Called Chemical digestion.
Using Enzymes (chemical scissors) to break food.
Enzymes are Specialized
The Tool
The Food
Just like a key only fits ONE lock,
Three Big Stops
Stomach
The mashing machine with acid.
Small Intestine
Where we absorb nutrients.
Large Intestine
Where we take back water .
Stomach Starter Warm Up Modified Stomach Starter
Level 1: Today's Warm-Up
1. What did you notice during the Cracker Challenge?
It tasted salty It tasted sweet
2. Draw a line to match the digestion type:
Mechanical
Chemical
Using chemicals to break food
Chewing and crushing food
3. Circle the place where digestion starts:
STOMACH MOUTH
Digestive Debrief Exit Ticket Modified Digestive Debrief
Level 1 Exit Ticket
Name:
1. Enzymes are like chemical _________________.
(a) Glue (b) Scissors (c) Paint
2. Where does food go AFTER the stomach?
Mouth Small Intestine Large Intestine
3. One thing I learned today is...
Digestive Debrief
Level 1 Exit Ticket
Name:
1. Enzymes are like chemical _________________.
(a) Glue (b) Scissors (c) Paint
2. Where does food go AFTER the stomach?
Mouth Small Intestine Large Intestine
3. One thing I learned today is...
Digestion Basics Study Guide Modified Digestion Basics
Level 1 Study Guide
The Path of Food
1
Mouth: Where food enters and is chewed.
2
Esophagus: The tube that carries food down.
3
Stomach: Mashes food and uses acid.
4
Small Intestine: Where nutrients go into the blood (Absorption).
5
Large Intestine: Where extra water is taken back.
Words to Know:
Mechanical: Physical mashing (chewing).
Chemical: Using enzymes to break food.
Enzymes: "Chemical scissors" that break food bits.
Bile: Liquid that breaks down fat.
How Enzymes Work:
Lock and Key:
Enzymes only fit ONE type of food because of their special shape. If the shape changes, the enzyme stops working!
Review Master Answer Key Modified Master Answer Key
Level 1 Modified Materials
Gut Tour Guided Notes (Mod)
Why digest: Energy
Mech: Surface Area
Chem: Enzymes
2: Esophagus
3: Stomach
4: Small Intestine
5: Water
Enzyme Basics Worksheet (Mod)
Matching: Enzyme -> Helper | Substrate -> Food | Specific -> One shape
True/False: 1. True | 2. False | 3. True
Which Enzyme: Pepsin
System Sprint Quiz (Mod)
MC: A) 2 | B) 1 | C) 2
Labeling: 1. Mouth | 2. Esophagus | 3. Stomach | 4. Small Intestine | 5. Large Intestine
Drawing: Key fitting into a lock (or shapes fitting together).
Exit Ticket (Mod)
1. Scissors | 2. Small Intestine | 3. Answers will vary.
