responses in plants and animals Flashcards
why do plants grow towards light
to maximise light absorption for photosynthesis
why do climbing plants have a sense of touch
so they can find things to climb up and reach the sunlight
what a tropism
a plants response to directional stimulus
what is a directional stimulus
a stimulus coming from a particular direction
how do plants respond to a stimuli
by regulating their growth accordingly
what is a positive tropism in terms of growth
growth towards a stimulus
what is a negative tropism in terms of growth
growth away from a stimulus
what is phototropism
plants response to light
what is gravitropism
plants response to gravity
what are growth factors
hormone like chemicals that speed up or slow down plant growth
where are growth factors produced
in the growing regions of plants such as shoot tips or leaves and move to parts of the plant where they’re needed
an example of a growth factor is auxins what do these do
stimulate the growth of shoots by cell elongation
what is cell elongation
when the cell walls become loose and stretchy so the cells get longer
what do high concentrations of auxins inhibit in roots
growth of roots
where is indoleacetic acid produced
in the tips of shoots in flowering plants
what does indoleacetic acid move by over short and long distances
1) short distances - diffusion and active transport
2) long distances - phloem
what does the uneven distribution of indoleacetic acid in the plant mean
different parts of the plant have different concentrations of indoleacetic acid which means there’s uneven growth
what is a tactic response (taxes)
when organisms move towards or away from a directional stimulus such as light
what is a kinetic response (kineses)
when organisms movement is affected by a non directional stimulus such as humidity
