Response To Stimuli

Question 1

what is kinesis?

Answer 1

resonse to stimui by changing rate of movement or turning without orientating to stimulus.
non-directional

Question 2

what is taxis?

Answer 2

oreintation and movement directly to or away from one or more stimuli.
directional response (determined by stimulus)
towards stimulus=positive taxis
away from stimulus=negative taxis
have prefixs to denote the type of stimulus

Question 3

what are the prefixes used when naming a taxis or tropism orientation?

Answer 3

gravi=gravity
photo=light
hydro=water
chemo=chemicals
thigmo=touch
thermo=temperature

Question 4

reason for taxis and kinesis:

Answer 4

helps maintain organisms in most favourable environment for survival so can reproduce

Question 5

what is a tropism?

Answer 5

growth of part of a plant in response to a directional stimulus
can be positive(toward stimulus)r negative (away from stimulus)
movement is by growth so is slow

Question 6

what do plants respond to maintain them in a favourable environment to survive?

Answer 6

light
gravity
water

Question 7

what are plant growth factors?

Answer 7

hormone like substances that plants produce as a response to stimuli
not hormones tho as not secreted into blood by glands. They work on tissues that make them.
e.g. indolaecetic acid (auxin)

Question 8

how does indolaecetic acid work?

Answer 8

1) produced in tip of shoot or stem
2) in unidirectional light, IAA diffuses down shoot away from tip
3) shaded side (lower) develops higher concentration of IAA than the illuminated side
4) IAA stimulates cell elongation
5) cells on shaded side elongate more than those on illuminated side#
6) unequal growth causes shoot or stem to bend towards light

inhibits elongation-has opposite effect