1. UNIT-6 PHOTOSYMTHESIS PRACTICAL’S
To show that dioxide is necessary for photosynthesis
GRADE 10-12.
SEME SECONDARY SCHOOL.
DUE DATE: 18 /11/2012.
GROUP WORK- SELECT (8) MEMBERS.
LIFE SCIENCES.
NOTICE: LATER SUBMITION 10% WOULD BE SUBTRATED
INSTRUCTIONS:
: Cover page
: Please make every effort to type or use a black pen
: 12 Point font (Arial or Time New Roman)
: Use 1.15 spacing
: Please number your pages
: Staple your practical on top of left corner
: Use picture and diagrams
: Colourfully
: Neatness
: List of references (Bibliography)
: Contents page and Index
(50 marks)
1
2. BACKGROUND INFORMATION OF THE PRACTICAL.
1. Summary
To determine whether carbon dioxide is needed for photosynthesis, a test for starch
could be carried out. When iodine solution is stained on the leaf, the green part of
the leaf will turned blue black. This means that starch is present. If starch is present,
the process of photosynthesis has occurred. From the equation above, glucose is
produce in the process of photosynthesis. However, in plants, glucose is converted
to starch. This is because starch is insoluble in water and it is a large molecule,
which cannot diffuse through the cell membranes.
2
3. 1. Safety aspects
Laboratory white coat
Closed shoes
2. Materials
1. One leaf
2. Beaker
3. Hot pot
4. Petri dish
5. Methylated spirits
6. Iodine solution
7. Forceps
8. White tile
3. Procedure
Two leaves were taken from two different plants. One leaf was taken from a potted
plant which was exposed to the atmosphere that contains carbon dioxide. Another
leaf was taken from a plant that was covered with a plastic bag and contains soda
lime that absorbs carbon dioxide.Destarch the plant by placing it in the dark for 72
hours (over a weekend is good). Small plants may be placed in a cupboard; large
plants can be covered by a polythene bag. The entire plant needs to be covered,
otherwise the products of photosynthesis may be translocated from
photosynthesizing parts of the plant to the covered parts of the plant, and the
destarching will be ineffective.
3
