| Plants at work : Plants at work |
| Plants are producers : Plants are producers Plants get their energy from light
Plants make food by photosynthesis
Light energy is trapped by chlorophyll
Most of the food is stored as starch |
| Photosynthesis Word equation : Photosynthesis Word equation
sunlight
Carbon dioxide + water sugar + oxygen
chlorophyll
Plants make new biomass during photosynthesis |
| Leaves : Leaves
Leaves are green because they contain chlorophyll
Leaves have a large surface area to absorb as much light as possible
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| Testing for starch : Testing for starch Iodine changes from brown to blue-black
where there is starch
Method
Soften the leaf with boiling water
Remove the green colour with ethanol
Add drops of iodine
Look for the colour change!
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| Variegated leaves : Variegated leaves Some leaves are not green all over
Some have white and green stripes or patches
Only the green parts will contain starch
Why?
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| Respiration in plants : Respiration in plants All living things carry out respiration
Leaves are thin so that gases can get in and out easily
Gases get into and out of leaves through little holes called stomata
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| Slide8 : Section through a leaf Waxy layer Palisade cells Spongy cells Air space Lower surface Guard cell Stomata |
| Plant growth : Plant growth Plants need carbon dioxide from the air
Plants need water
Plants need light
Plants need nutrients from the soil including nitrogen, phosphorus and potassium
If the soil does not contain enough nutrients then we add fertilisers |
| Fertilisers : Fertilisers Nitrogen is needed for general growth
Phosphorus is needed for healthy roots
Potassium is needed for healthy leaves |
| Plant plumbing : Water and minerals enter the plant through the roots
Then they go up through little tubes called xylem in the plant stem
Food is transported through tiny tubes in the stem called phloem Plant plumbing |
| Roots : Roots keep the plant anchored in the soil
Roots are covered in lots of tiny hairs
Root hairs take up water from the soil
All the root hairs together have a large surface area Roots |
| Flowers : Flowers are a plant’s reproductive system
Flowers have male and female reproductive organs
Male part (stamen): anther and filament
Female part (carpel): stigma, style, ovary Flowers |
| Pollination : Pollination is the transfer of pollen (male) to the stigma (female)
Pollen grains can be carried by insects
Pollen grains can be carried by the wind
When the ovule is fertilised it turns into a seed Pollination |
| Making seeds : Making seeds stigma Pollen grain ovary style ovule
nucleus ovule |
| Key words : Key words plant
seed
root
stem
leaf
root hair
starch chlorophyll
photosynthesis
carbon dioxide
oxygen
phosphorus
nitrogen
potassium pollen
anther
filament
stigma
style
ovule
xylem
phloem |