Biology 5.4.1 Flashcards
Which Plant Hormones Coordinate & Control Growth?
Auxins.
Plants need to be able to Grow in Response to ___ and ___.
Light, Gravity.
The Shoots of a Plant must Grow ___, away from ___, & towards ___. Why?
Upwards, Gravity, Light. So that the Leaves are able to Absorb Sunlight.
The Roots of a Plant must Grow ___, away from ___, & towards ___. Why?
Downwards, Light, Gravity. In order to Anchor the Plant, & Absorb Water & Mineral Ions from the Soil.
What is ‘Gravitropism’?
Growth Towards or Away from Gravitational Pull.
What is ‘Phototropism’?
Growth Towards or Away from Source of Light.
Where are Auxins being Produced in Plants?
In the Tips of the Roots & Shoots.
In the Shoots, Auxins ___ Cell Elongation (Growth).
Promote.
In the Shoots, More Auxins = …
More Cell Elongation (More Cell Growth).
In the Roots, Auxins ___ Cell Elongation (Growth).
Inhibit.
In the Roots, Less Auxins = …
Less Cell Elongation (Less Cell Growth).
What is the Distribution of Auxin in the Shoots Affected by? (2)
-Light.
-Gravity.
What is the Distribution of Auxins in the Roots Primarily Affected by?
Gravity.
What does ‘Unequal Distribution’ of Auxins Cause in Plant Roots & Shoots?
Unequal Distribution of Auxins Cause Unequal Growth Rates in Plant Roots & Shoots.
Explain the Process of how Auxins Stimulate Growth in Plant Shoots (Positive Phototropism)? (4)
-Auxins are made (Synthesised) in the Tips of the Shoots.
-In the Prescence of Strong Directional Light, Auxins Diffuse Away from it, Towards the Shaded Side.
-Uneven Growth is Caused by the Uneven Distribution of Auxins.
-Auxins will Increase Growth of Cell in Meristem, so will Cause Shaded Side to Grow & Elongate Faster than the Side in the Light.
