Transcript Digestion Practical Work Sheet

Digestion
Practical Work
Sheet
Amy Barton
City and Islington College
Student Name: …………………………………………………………………………
Topic
Digestion
Aims
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It provides a practical demonstration of the digestion process – this
worksheet helps tease out the understanding of students as they go through
the process.
The learners enjoy this practical activity and the worksheet helps them think
in practical terms about the steps involved in each process they undertake.
Level
Level 2
Method
PowerPoint slides, with Practical Work Sheets, Health and Safety Requirements
and Equipment Requirements.
Equipment
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Laptop & Projector
The gut bag is a thick plastic bag that mimics the human digestive tract.
Students use food and acids to recreate the digestive process, from
mastication, chemical and mechanical digestion, to defecation. The gut
bag is officially called Digesto-Rama bags and you can get these from
Scientific and Chemical Supplies at £20.57 for a pack of two.
Mortar and Pestle, Hydrochloric Acid, Bicarbonate of Soda, Stickers, Chyme,
Antacid Pill, Bucket, Benedict's Solution
Hand-outs (ALL Slides to print, apart from Slide 2)
Pens
Duration
20 – 30 Minutes
Digestion Practical
Work Sheet
Read the lab rules and the labels on the chemicals you have been
given. Ensure you all have a hand-out and pen, you will be working in
a group, all must contribute to the group.
Health and Safety Requirements
Laboratory coats (buttoned up)
Universal Indicator
Hydrochloric Acid – Gloves and care required
Equipment Requirements
Most items are at the front of the class
Some equipment will be in the cupboards
Pens are needed to write down your results
Best used with the ‘gut bag’ this is commercially available
Digestion Practical
Work Sheet
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Use the mortar and pestle to roughly grind your food (use 2
crackers, leave some lumpy bits).
Q: What type of digestion does this represent?
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Q: Where does this happen in our body, name the organs involved?
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Digestion Practical
Work Sheet
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Add a small amount of water to the food to make a paste.
Pipette in a small amount of the Universal Indicator (this tells
you the pH)
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Add amylase to the mixture and mix it in
Q: What is amylase and what does it do to starch?
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Q: Where does amylase act in the digestive system?
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Digestion Practical
Work Sheet
•
Feed the paste (using the spatula) into the ‘mouth’ of the
digestive tract. Use your hands to push the food into the
stomach, one student hold the bag upright and another push
the food.
Q: What is then name of the wave of muscle movement that moves
food through the digestive tract?
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Q: What is the name of the tube that links the mouth and the
stomach?
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Q: What colour is the food with the Universal Indicator, what pH is
this?
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Q: What is the name of the food as it passes into the stomach?
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Digestion Practical
Work Sheet
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When the food is in the stomach, add Hydrochloric Acid ***be
very careful as this is acidic, do not get it on your skin***
Q: What type of digestion is this?
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Use your hands to churn the food, do this for 5 whole
minutes (this this job within the group)
Q: What type of digestion is this?
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Q: What is the food/acid mixture called now?
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Q: What colour is the food/acid Universal Indicator now, what pH is
this?
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Now add bicarbonate of soda to the stomach. This should
produce some gas
Q: What normally happens to gas in the digestive track?
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Now use the stickers to label the digestive tract. Use all of
the words you can think of, be careful to use the correct
spelling (see your class notes).
Digestion Practical
Work Sheet
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Only after 5 minutes of churning, and finishing all of the
tasks, push the chyme into the intestine.
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Grind up an Antacid pill into a fine powder. Add water and
push it into the intestine.
Q: What colour is the food/acid/Universal Indicator now?
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Q: What change do you think has happened to the pH?
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Q: Where does the food you eat undergo a dramatic pH change in
your digestive track?
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Q: What organ ensures a pH change after the stomach (think
carefully about this answer, use your class notes)?
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Digestion Practical
Work Sheet
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After you show your tutor your work so far, you can move the
food out of the stomach and through the rest of the digestive
tract.
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Share the task of moving the food through the digestive tract
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Empty the food mixture into a bucket. Place some of the
mixture back into the mortar and pestle
Digestion Practical
Work Sheet
Q: What is the name of the ring of muscle that stops food leaking out
of the stomach or rectum?
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Q: Where does the food move into when it leaves the stomach?
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Q: Why is it good that you have a very long small and large intestine?
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Q: Why is it good that indigestible food is stored in the rectum?
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Add Benedict’s solution to the mix.
Q: What colour has it turned? What does this indicate?
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