Response to stimuli
Organisms increasestheir chances of survival by responding tostimuli1changes intheir
environment
Taxis Unidirectional response where thedirectionof organisms movements is
determined
by the stimulus eg positive phototaxis
kinesis A response whereanimals move more rapidly andchangedirectionmorefrequently
in response to an unplesantstimulus
Tropism Thegrowthmovement of a plant in response to a directionalstimulus
Mechanisms to Induce Response
Nerves Unidirectional electrical impulses whichsecrete neurotransmitters directly onto the
target organ Fastactingand short lived exceptadrenaline
Hormones Specific chemical messenger carried in theblood Slowacting and longlasting
Histamines local chemicalmediators released by somecells and diffuse to affectcell
only in their vicinity
Vasodilation inflammatory response
Eg
Indole AceticAwdCIAA Growthfactor released
by men'stematicgrowingregions in plants
TypeofAmin
beforediffusing to produce a response to directional stimuli
, Notonspec Applicationquestion
arepositively
light
f
Sphoots
hitotrophic
Thetip is responsible
fordetectingstimulus
orproducing a signal
orboth
Tipresponsiblefor
GABBA
detecting
light
ammo Messengerchemical
IN
oarowelenitiecashmagueing
mica
sideoftheshort
ammo
3 Momoa
Organisms increasestheir chances of survival by responding tostimuli1changes intheir
environment
Taxis Unidirectional response where thedirectionof organisms movements is
determined
by the stimulus eg positive phototaxis
kinesis A response whereanimals move more rapidly andchangedirectionmorefrequently
in response to an unplesantstimulus
Tropism Thegrowthmovement of a plant in response to a directionalstimulus
Mechanisms to Induce Response
Nerves Unidirectional electrical impulses whichsecrete neurotransmitters directly onto the
target organ Fastactingand short lived exceptadrenaline
Hormones Specific chemical messenger carried in theblood Slowacting and longlasting
Histamines local chemicalmediators released by somecells and diffuse to affectcell
only in their vicinity
Vasodilation inflammatory response
Eg
Indole AceticAwdCIAA Growthfactor released
by men'stematicgrowingregions in plants
TypeofAmin
beforediffusing to produce a response to directional stimuli
, Notonspec Applicationquestion
arepositively
light
f
Sphoots
hitotrophic
Thetip is responsible
fordetectingstimulus
orproducing a signal
orboth
Tipresponsiblefor
GABBA
detecting
light
ammo Messengerchemical
IN
oarowelenitiecashmagueing
mica
sideoftheshort
ammo
3 Momoa
