Response Flashcards
5 things animals respond to
light sound hunger pain presence of foreign cells
3 ways in which animals respond
movement
production of chemicals (enzymes, hormones)
production of cells eg. lymphohocytes
4 things that animals need to carry out a response
sense organs and a nervous system
hormonal system
muscular and skeletal system
immune system
5 stimuli that plants respond to
light, gravity, touch, H2O or chemicals
2 ways in which plants respond
changing their pattern of growth (growth regulation)
germinating, flowering, becoming dormant
what are plant responses due to?
the action of chemicals called growth regulators
speed of plant responses
much slower than animal responses
4 external factors that regulate the growth in plants
light intensity
day length
gravity
temperature
how does light intensity act as a growth regulator
affects the rate of photosynthesis and growth
how does day light act as a growth regulator
it varies with the seasons, has major effects on seed germination, flowering, seed dormancy and leaf fall
how does gravity act as a growth regulator
it ensures that roots grow downwards and shoots grow upwards
how does temperature act as a growth regulator
heat (high temperatures) promotes growth by increasing the rate of enzyme activity
main internal factor of growth regulation in plants
the production of chemicals called growth regulators in the meristems
Growth regulators
chemicals produced by a plant that control its growth and development
how do growth regulators get to where they need to be
they are produced in one part of the plant eg. meristems and they are transported to another part of the plant where they cause a response in vascular tissues
comment on the speed of growth regulators
slow acting but with a long-lasting effect
what does their effect depend on?
their concentration and the location in the plant in which they act
higher concentration of auxin
stimulate growth in shoots and inhibit growth in roots
lower concentration of auxin
cause more growth in rots and no effect on shoot growth
how do growth regulators interact with each other and give an example
interact with each other in controlling growth and development eg. auxins and gibberellins together promote cell elongation in stem
5 commercial uses of plant regulators
rooting powders tissue culturing selective weed killers formation of seedless fruits ripening of fruit
explain rooting powders as a commercial use of plant regulators
horticulturists use NAA to promote rooting of stem cuttings