Transcript Photosynthesis PPT

Photosynthesis
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What do you think Steve eats?
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What do you think chicken eats?
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What do you think worms eats?
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What do you think plant eats?
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Do you think plant eat soil?
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How do we know whether
plant eat soil for their
survival?
HOW DO WE TEST FOR IT?
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How do we know whether
human need oxygen to
survive?
HOW WOULD YOU TEST FOR THE
REQUIREMENT FOR OXYGEN?
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LET’S TEST WHETHER HUMAN
REQUIRES OXYGEN TO SURVIVE!
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How do we know whether
plant eat soil for their
survival?
HOW DO WE TEST FOR IT?
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Let’s see how this gentlemen test out
whether plant eat soil to grow!
Dutch biologist, Jean Baptist Van
Helmont conducted an experiment. In
1652
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After 5 years, the willow tree grew to 77 Kg! How
did the willow tree gain so much weight? Did it eat
the soil?
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Aeroponics – Plants can grow
without soil! Just water and
nutrients are enough.
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Photosynthesis
Photo means light and synthesis
means put together.
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Photosynthesis is how plants use light
and water to make sugar. Sugar is
created in the green parts of a plant
and every animal on earth depends on
it. Without plants we would have no
food to eat or oxygen to breathe.
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Equation for Photosynthesis
1.Light Energy
2.Chlorophyll
Carbon
dioxide
+
Water
Glucose
This equation is very important!
+
Oxygen
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Glucose is used for plant growth and
excess glucose is converted to starch
Glucose
Excess is
converted to
Growth and
energy
Starch
Stored up!
E.g. Potato
Iodine is use to test for the presence of
starch. Turns blue black!
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Do you think glucose and starch will be
produced if no light is given?
1.Light Energy
2.Chlorophyll
Carbon
dioxide
+
Water
Glucose
+
Oxygen
Is light necessary for photosynthesis?
1.Take a destarched potted
plant as shown in the
diagram.
2.Leave in strong sunlight for
a few hours.
3.Pluck out leaf X and test for
starch.
Leaf X
(From: http://faculty.ntcc.edu/mhearron/photosynthesis.htm)
Observation
Yellowish-brown on
part not exposed to
light  showing
absence of starch
(Diagram from: http://faculty.ntcc.edu/mhearron/photosynthesis.htm)
Blue-black colour on
parts of leaf exposed
to light  showing
presence of starch
Do you think glucose and starch will be
produced if no carbon dioxide is given?
1.Light Energy
2.Chlorophyll
Carbon
dioxide
+
Water
Glucose
+
Oxygen
Is carbon dioxide necessary for
photosynthesis?
Potassium hydroxide absorbs the carbon
dioxide in the glass jar.
Is chlorophyll necessary for
photosynthesis?
In variegated leaves, where part of the leaf do
not have chlorophyll, starch is not formed!
(From: http://faculty.ntcc.edu/mhearron/photosynthesis.htm)
Overview of Photosynthesis **
Photosynthesis needs:
1. carbon dioxide
(from the air)
Raw
2. water
materials
(from the soil)
3. chlorophyll
4. sunlight energy
(any light will do
except green light)
Conditions
Photosynthesis
produces:
1. glucose
2. oxygen
(a waste product)
Light energy
-Is converted into chemical energy in the
form of carbohydrates (glucose)
Glucose
-This takes place through a series of
chemical reactions
-Glucose is formed during photosynthesis.
-Carried to all parts of plants by phloem.
-Excess glucose is stored as STARCH.
Carbon dioxide
-Enters by diffusion
Oxygen
-Enters through stomata (tiny
pores in the leaves)
-Escapes into the air by diffusion
-Exits through stomata of the
leaves
Chlorophyll present in leaf
-Found in chloroplasts
-Helps to absorb light energy from
the sun
Water
Word equation for photosynthesis:
-Obtained from soil
-Enters plant by osmosis
-Taken to leaves by xylem
Fun experiment!
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Let’s grow some beans!
Form a pair
Take 5 red beans and 5 black beans
Let’s see who can grow the tallest bean plant!
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