GROUP ASSIGNMENT :RESPIRATION AND PHOTOSYNTHESIS
DAY ISSUED: 27 JANUARY 2016 SUBMITION DATE: 3 FEBRUARY 2016
Practical activity 1
Group: five members in each group
Investigate if plants produce starch in their leaves
AIM: To test for the presence of starch in the leaves of plants
YOU WILL NEED:
- Green leaf from a healthy plant that has been growing outside
- A glass beaker or container
- Water
- Bunsen burner or spirit burner
- Tripod
- Gauze
- Test tube
- Ethanol
- Forceps
- White tile or other white surface
- Iodine solution
- Dropper
- Timer
Method
1. Heat a beaker of water on the tripod stand with gauze over a Bunsen burner until the water boils.
2. Use the forceps to put the leaf in the boiling water for one minute.
3. Switch off the Bunsen burner.
4. Use the forceps to remove the leaf from the water and place it into a test tube filled with ethanol or methylated spirits.
5. Place the test tube in the beaker of hot water (the water must not be boiling). Do not let the water flow into the test tube. The ethanol will boil because it has a lower boiling point than water. This step removes the chlorophyll from the leaf so that it does not mask the colour of the iodine solution later in the test.
6. Use the forceps to take the leaf out of the test tube and rinse it in the hot water in the beaker.
7. Use the forceps to place the leaf gently on the white tile.
8. Use the dropper to add a drop of iodine solution to the surface of the leaf. Observe any changes.
Questions
1. What colour was the leaf when you.
A) Removed it from the boiling water
B) Rinsed it after removing it from the ethanol?
2. What colour was the iodine solution
A) Before it was placed on the leaf?
B) When it came into contact with the leaf?
3. What does the change in colour in Question 2 indicate?
Results
Write a report on this investigation using the headings: Aim, Hypothesis, Method,
Results, Discussion and Conclusion. Rubric to assess practical work and report
Rubric
to assess practical work and report
Criteria
|
Level 4
[4]
|
Level 3
[3]
|
Level 2
[2]
|
Level 1
[1]
|
Learners
were able to complete practical work independently by following instructions.
|
Outstanding.
|
Good.
|
Satisfactory.
|
Poor.
|
Learners
were worked consistently through period of practical work, making diligent
observations of the leaf
|
Outstanding.
|
Good.
|
Satisfactory.
|
Poor.
|
Learners
were able to conclude. Aim,
Hypothesis, Method, Results, Discussion and Conclusion of the experiment
|
Outstanding.
|
Good.
|
Satisfactory.
|
Poor.
|
Learners
were able to conclude the effect of boiling water, ethanol, and iodine
|
Outstanding.
|
Good.
|
Satisfactory.
|
Poor.
|
