Plants Flashcards
What is the function of the stem
Support and transport materials to the upper parts of the plant
Some stem leaves store food eg celery and rhubard
What is the function of the leaves
Make food,exchange gases and allow water to pass out
What do the buds do
Future growth points
What is the function of flowers
Produce seeds for reproduction
What is the function of the roots
They anchor the plant and take in water and minerals
Some roots store food eg carrots and potatoes
What is photsynthesis
The way in which green plants make their own food
What is the word equation for photsynthesis
Carbon dioxide+water —— sunlight+chlorophyll = glucose + oxygen
What are the factors of photosynthesis and what do they do?
Carbon dioxide:
Enters the under surface of leaves through tiny openings called stomata.
Water:
Enters the roots from the soil
Passes up from the stem in tubes called xylem
Light:
Sunlight, provides the energy for photosynthesis
Chlorophyll:
Is a green pigment or dye made by plants
Absorbs light
What are the products of photosynthesis?
Glucose- used for respiration, stored as starch and makes cell walls
Oxygen-respiration, passes out of the stomata into the air
Describe and experiment to show that starch is produced during photosynthesis
Put a plant in darkness for 24 hours to de-starch.
Put in sunlight for 24 hours.
Put tinfoil on some leaves to block out light and prevent photosynthesis. These leaves act as a control.
Place the plant in strong light for a few hours, allowing photosynthesis to take place.
Test the leaves for starch
Describe how to test leaves for starch
1.Place green leaves in boiling water to kill and soften the leaves.
2.Soak the leaves in hot alcohol to remove chlorophyll
The alcohol turns green as chlorophyll dissolves in it.
Heat alcohol by placing in boiling water
- Place the now brittle leaves into boiling water to soften them.
- Place the leaves on a white surface and cover them with iodine solution.
The uncovered leaves turn a blue black colour as they contain starch.
The covered leaves remain a red yellow colour as they not contain starch.
Conclusion: starch is produced by plants in photosynthesis
What is tropism
The change in growth of a plant in response to an outside stimulus
What is phototropism
The change in growth of a plant in response to light.
The shoots of a plant grow towards the light due to to phototropism.
How would you investigate phototropism
Petri dish containing wet cotton wool sprinkled with seedlings
What is geotropism
The change in growth of a plant in response to gravity.
The shoots of a plant grow away from gravity, growing upwards towards the light.
Why do the plants roots grow downwards
They grow into the soil to get a better grip and absorb water
Describe an experiment to investigate geotropism
Soak some large seeds in water for a day or two to allow them to germinate.
Line a beaker with filter paper.
Support the compost with damp soil and place the seeds between the paper and the glass.
Leave the jar in a warm dark place.
The seeds grow and the roots shoot downwards while the shoots grow upwards.
This shows that roots grow downwards towards gravity while shoots grow upwards away from gravity.
What are the two types of plant transport tissue?
Xylem- transports water and dissolved minerals.
Phloem- transports food
What is transpiration
The loss of water from a plant
What is the transpiration stream
The flow of water from the roots of the stems and into the leaves
What is the stomata
Tiny holes on the surface of the leaf where most transpiration occurs
What are the functions of transpiration
- Supplies leaves with water for photosynthesis.
- Supplies plants with minerals (dissolved in water)
- Helps cool plants down
What factors affect transpiration
Humidity: transpiration slows down if the leaf is already surrounded by moist air
Temperature: faster with higher temperatures
Wind: faster in windy conditions as water vapour is removed quickly by air movement
Soil water content
Describe an experiment to show the path of water through a plant
Place a piece of celery in coloured water.
Leave for a few days.
Cut the stalk.
Observe the path taken by the coloured water as it moves through the plant.
