•
Class: MYP Year 4 – Grade 9
•
Criterion C : Processing and evaluating
•
Unit title: Digestion
•
Statement of Inquiry: Energy and balance within a system can maintain an individual’s health and wellbeing.
Date: ____/09/2022
Name:
•
Grade: 9 A / B
The questions in this report will assess you on criterion C.
You should attempt all the questions
Refer to the rubric in page 2 to make sure you are answering correctly.
•
You have achieved a level:
•
What could you do next time to improve your achievement level?
Page 1 of 9
Criterion C: Processing and evaluating
Achievement
level
0
Level descriptor
The student does not reach a standard identified by any of the descriptors below.
The student is able to:
1–2
i.
collect and present data in numerical and/or visual forms
ii.
interpret data
iii.
state the validity of a hypothesis with limited reference to a scientific
investigation
iv.
state the validity of the method with limited reference to a scientific
investigation
v.
state limited improvements or extensions to the method.
The student is able to:
i.
correctly collect and present data in numerical and/or visual forms
ii.
accurately interpret data and describe results
iii.
state the validity of a hypothesis based on the outcome of a scientific
investigation
iv.
state the validity of the method based on the outcome of a scientific
investigation
v.
state improvements or extensions to the method that would benefit the scientific
investigation.
3–4
The student is able to:
i.
correctly collect, organize and present data in numerical and/or visual forms
ii.
accurately interpret data and describe results using scientific reasoning
iii.
outline the validity of a hypothesis based on the outcome of a scientific
investigation
iv.
outline the validity of the method based on the outcome of a scientific
investigation
5–6
outline improvements or extensions to the method that would benefit the scientific
investigation.
The student is able to:
v.
7-8
i.
correctly collect, organize, transform and present data in numerical and/ or visual
forms
ii.
accurately interpret data and describe results using correct scientific reasoning
iii. discuss the validity of a hypothesis based on the outcome of a scientific investigation
iv.
discuss the validity of the method based on the outcome of a scientific investigation
v.
describe improvements or extensions to the method that would benefit the scientific
investigation.
Page 2 of 9
Command Terms Reference:
Command Term
Definition
Describe
Give a detailed account or picture of a situation,
event, pattern or process.
Identify
Provide an answer from a number of possibilities.
Recognize and state briefly a distinguishing fact or
feature.
Verify
Provide evidence that validates the result.
Discuss
Offer a considered and balanced review that includes
a range of arguments, factors or hypotheses. Opinions
or conclusions should be presented clearly and
supported by appropriate evidence
Determine
Suggest
Obtain the only possible answer
Propose a solution, hypothesis or other possible
answer
Page 3 of 9
Topic Overview:
One of the factors for the “Well-being” of individuals is to have a balanced food diet. A balanced diet
provides all required raw materials for the proper building and function of our body. From energy
production to immunity and cell division: all processes need nutrients provided from food.
Different organic polymers are composed of different monomers connected by different types of bonds.
In this session, the presence of different type of organic compounds will be tested in different types of
food.
“Complex Food” is a term used to describe a certain type of food that is qualitatively balanced – this
means it contains many different organic compounds.
Check the following table for different biochemical tests (reagents) used to identify the presence of
different organic compounds. These are qualitative tests that do not give us values, however, they help
in identifying content.
Compound Tested
(substrate)
Reagent (dissolved
in water =
aqueous)
Iodine
Initial Color
Positive Result
Special
Conditions
Brown-orange
Dark Blue
None
Reducing Sugars
(Carbohydrate)
Fehling-Benedict
Test
Blue
Brick-red
precipitate
Requires Heat
Proteins and
Polypeptides
Biuret Test (copper
sulfate + sodium
hydroxide)
DCPIP
Blue
Violet color
None
Blue
Colorless
None
Starch
(Carbohydrate)
Vitamin C
Notes about the Vitamin C Test:
Page 4 of 9
Test for Lipids (fats):
As for Lipids, they are insoluble in water: this means that
we can not make an aqueous solution of fat or oil on which
to carry out a biochemical test → we need to perform a
physical test called “emulsion test” to test for lipids.
The steps to perform emulsion test are represented in the
adjacent figure:
Hypothesis and Aim:
A scientist suggested that all food contains all types of organic material.
In order to validate this hypothesis, the tests above are performed on different food groups and the results obtained
will then be recorded.
Procedure(s)
❖ Test for starch:
1. Place a small amount of food on the
spotting tile.
2. Add a few drops of iodine solution to the
food on the spotting tile.
3. Yellow–red iodine solution turns blue–
black if starch is present.
4. Repeat steps 1–3 for other types of food.
5. Record all your results in a results table.
❖ Test for sugar:
1 Place a small amount of food in a test tube.
2 Add enough Benedict’s solution to cover
the food.
3 Place the test tube in a warm water bath for
10 minutes.
4 Blue Benedict’s solution turns brick red on
heating if a sugar such as glucose is
present.
5 Repeat steps 1–4 for other types of food.
6 Record all your results in a results table.
❖ Test for protein:
1 Place a small amount of food in a test tube.
2 Add 1 cm3 of Biuret reagent. Alternatively,
add 1 cm3 of sodium hydroxide solution
and then add a few drops of copper sulfate
solution.
3 Blue Biuret reagent turns purple if protein is
present.
4 Repeat steps 1–3 for other types of food.
5 Record all your results in a results table.
❖ Test for lipids (fat):
1 Place a small amount of food into a test
tube.
2 Add a few drops of ethanol to the test tube.
3 Shake the test tube and leave for one
minute.
4 Pour the solution into a test tube of water.
5 Ethanol added to a solution gives a cloudy
white layer if a lipid is present.
6 Repeat steps 1–5 for other types of food.
7 Record all your results in a results table.
Page 5 of 9
A. Raw Data Collection:
Fill in the following table with the result observed after performing each test.
Food
Iodine test
Fehling test
Biuret test
DCPIP
Emulsion test
Grapes
yellow
Brick-red
blue
blue
No change
Banana
Dark blue
Blue
blue
colorless
No change
Potatoes
Dark blue
Blue
Blue
Blue
No Change
Egg White
Yellow
Blue
Violet
Blue
No Change
Milk
Yellow
Brick-red
precipitate
Violet
Blue
No Change
Oil
Yellow
Blue
Blue
Blue
White emulsion
formed
Bread
Dark blue
Blue
Violet
blue
White emulsion
formed
B. Processed Data:
Referring to the table in section A, identify the organic constituent of each food used by filling the table below.
Food
Positive Observation(s)
Grapes
Banana
Potatoes
Egg White
Page 6 of 9
Inference(s)
Milk
Oil
Bread
C. Results Interpretation
1. Describe the process of performing Biuret Test on the piece of bread. Make sure to use the legends.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
2. The teacher carried out a risk assessment before she started this practical test for proteins in bread.
Complete the following risk assessment for testing a food for the presence of protein.
Hazard
Risk
Biuret Reagent
Bench contamination
Page 7 of 9
Control
3.
“Bread is a complex food.” Verify this statement.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
4. “A scientist suggested that all food contains all types of organic material.”
Based on the results, discuss the validity of the scientist’s hypothesis.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
5. Choose one of the methods used to discuss whether this method is valid and enough for proper
identification of food constituents.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
6. Rami suffers from a disease called “diabetes”. He can’t have a lot of sugar per day.
For this reason, the Dr. limited carbohydrate intake for a maximum of 130 grams per day.
Now, Rami wanted to have a piece of dessert. He suggested to perform iodine test to know if he can have this
dessert or not in order to maintain his well-being.
5.1 Discuss if performing Iodine test is enough for Rami to maintain his well-being by having the dessert.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
Page 8 of 9
5.2 After doing some research, describe an improvement or an extension to the method of iodine test that
would benefit Rami to make a proper decision.
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
__________________________________________________________________________________________
Page 9 of 9