The Effect of Light on the Size of Ivy Leaves
Design an experiment to investigate if light affects the size of Ivy
In this experiment I will explore how light affects the size of Ivy
leaves. I will use the common Ivy called Hedera helix. I will take two
stems of Ivy, one from the part of the garden that is exposed to lots
of light, and one which exposed to little light. The Ivy leaves that
are facing the south of the garden will have been exposed to high
light intensities, whereas the leaves facing the North of the garden
will have been exposed to low light intensities. Although the Ivy
leaves are ...view middle of the document...
It is the
pigment chlorophyll, which traps the light. Photosynthesis takes place
in the green parts of the plant, in particular the leaves. Since
plants produce their own food via photosynthesis they are called
autotrophs. Therefore, they are photoautotrophs, because their energy
source is light.
In photosynthesis there are 2 main reactions that occur, the light
dependent reaction and the light independent reaction. Obviously the
light dependent reaction can only occur in light. The light
independent reaction may not need light, but if the light dependent
reaction does not occur, then the light independent reaction cannot
occur, because the products of the light dependent reaction are needed
in the light independent reaction.
* Light dependent reaction:
- this occurs in the chloroplasts
- it makes ATP from iP, this is called photophosphorylation.
- Water is split by photolysis to give H+ ions, which are picked up by
the energy carrier NADPH
- Light is what provides the energy. Therefore, the light energy
excites electrons in chlorophyll. This energy is used to generate ATP
and NADPH, and photolysis makes H+ ions available for the light
- Oxygen is also released from this reaction.
* Light independent reaction:
- This occurs in the stroma
- Light is not needed to provide the energy, because the ATP produced
in the light dependent reaction is what produces the energy.
Light intensity must affect the size of Ivy leaves, because the rate
photosynthesis increases as the light intensity increases. So if the
rate of photosynthesis increases, the size of the leaves must