Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
24 Cards in this Set
- Front
- Back
|
what are three ways that plants increase their chances of survival
|
they increase their chances of survival by responding to their environment in 3 ways
1)they sense the direction of light and grow towards it to maximize light absorption for photosynthesis 2)they can sense gravity so their roots and shoots grow in the right direction 3)climbing plants have a sense of touch so they can find things to climb and reach the sunlight |
|
|
what is a tropism
|
a tropism is a plants response to a directionl stimulus
|
|
|
how do plants respond to a stimulus
|
they respond to a stimulus by regulating growth
|
|
|
what is a positive tropism
|
a growth towards a stimulus
|
|
|
what is a negative topism
|
growth away from a stimulus.
|
|
|
what is phototropism
|
is the growth of a plant in response to light
|
|
|
do shoots grow towards or away from the light, and why?
|
shooots grow towards the light because they are positively phototropic
|
|
|
do roots grow towards or away from the light and why?
|
roots grow away from the light because they are negatively photo tropic
|
|
|
what is geotropism
|
the growth of the plant in response to gravity
|
|
|
are shoots negatively or positively geotropic and why
|
shoots are negatively geotropic and grow upwards
|
|
|
are roots positively or negatively geotropic and why
|
roots are positively geotropic because they grow downwards
|
|
|
how do plants respond to stimuli
|
they respond to stimuli using growth factors
|
|
|
what are growth factors
|
chemicals that speed up or slow down plant growth
|
|
|
where are growth factors produced in a plant and where do they move to
|
they are produced in the growing regions of the plant e.g shoot tips, leaves
-and they move to where they're needed to other places in the plant |
|
|
what does gibberellin do
|
it stimulates flowering and seed germination
|
|
|
what does the growth factor auxin do
|
it stimulates the growth of shoots by cell elongation
|
|
|
what is cell elongation
|
where the cell walls become loose and stretchy so the cells get longer
|
|
|
what does high concentrations of auxin do to a plants growth
|
high concentration of auxin inhbit growth in roots though
|
|
|
what is indoleacetic acid (IAA)
|
its an important auxn thats produced in the tips of shoots in flowering plants
|
|
|
what is the role of IAA
|
it is moved around the plant to control tropisms
|
|
|
how does it move around the plant
|
it moves by diffusion and active transport over short distances and via the phloem over long distances.
|
|
|
what does the uneven distribution of IAA in the plant mean in terms of the plants growth
|
this means there is an uneven growth in the plants
|
|
|
how does the movment of IAA control growth of shoots and roots in phototropism
|
IAA moves to the more shaded parts of the shoot. on the side of the shoot it has moved to the cells there elongate and the shoot bends towards the light.
if the IAA moves to the opposite side growth is inhibited so the root bends away from the light |
|
|
how does the movement of IAA control the growth of shoots geotropism
|
the IAA moves to the underside of the shoot and root so there's uneven growth. the side of the shoot that IAA moves to the cells elongate so the shoot grows upwards
- if IAA moves to the opposite side growth is inhibited, so the root grows downwards |
