Topic 6 Flashcards
What is a stimulus?
A detectable change in the environment.
How can stimulus be detected?
By cells called receptors
How can organisms increase their chance of survival?
By responding to stimuli via different response mechanisms.
What is tropism?
The term given to when plants respond via growth to stimuli.
Tropism can be positive or negative growing towards or away from a stimulus. Plants respond to light and gravity.
Tropisms are controlled by specific growth factors and one key example is indoleacetic acid.
What is indoleacetic acid?
A type of auxin and can control cell elongation in shoots and inhibits growth of cells in the roots. It is made in the tip or the roots and shoots but can diffuse into other cells.
What is phototropism?
Light is needed for the light dependent reaction in photosynthesis so plants can grow and bend towards light. This is positive phototropism.
