Flashcards · Biology · Plant Hormones
Investigating Plant Responses
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What is required practical 8?
Investigate the effect of light or gravity on the growth of newly germinated seedlings.
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How must the results be recorded?
As length measurements and as labelled biological drawings.
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What is the independent variable for light?
The direction of the light.
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What is the dependent variable?
The length and the direction of growth of the shoots or roots.
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Why is a tray kept in the dark?
As a control, to show growth without light.
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Why are the gravity dishes kept in the dark?
So that light does not affect the direction of growth.
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What does a clinostat do?
Turns seedlings so gravity acts on all sides equally.
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Name two control variables.
Any two from: type of seed, number of seeds, volume of water, temperature, distance from the lamp.
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What should a biological drawing have?
Clear single lines, no shading, labels and a scale.
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What does a resolution of 1 mm mean?
The ruler can detect changes of 1 mm.
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What does repeatable mean?
The same person gets similar results.
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What does reproducible mean?
Other people get similar results.
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How could the results be made more reliable?
Use more seedlings and repeat the investigation.
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Why is the lamp a problem?
It can warm the seedlings on one side.
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Why wash hands after the practical?
Mould and bacteria can grow on damp seeds.
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Common mistake in a biological drawing?
Using shading and colour, and not labelling the drawing.