In depths mindmaps of sub- topics within Topic 6 (Organisms respond to changes in their internal + external environment) of Alevel biology Notes are formed with markscheme points within it and diagrams. Have some extra information to help with essay writing.
impulses
-
SAN) Sinoahial model
-
AVN (atrioventricular nodel
-
It is bundle/purkyne fibres
, Responses by simple organisms
I
Kinesis
Taxis
Funa
until suitable environment is found
Organism will help moving toward
a
-
either
-
Directed movement of an organism
-non-directed movement
from stimulus
away
a
caused
In response stimulus e g light ↳ in a movement
howardpositivisesingatedalga morvan
-
to
-
-
nearer the favourable by stimulus
Rale of movement will decrease when
conditions/furer hom unfavourable
moving
light gets brighter skys
+
it
E g
.
.
wor will more guide
environment is found
When dark
&
↓
Survival + Response
I
Plant response to Stimuli Phototrogism -
plants bend towards the light as the planks
sideo a
slightly faster he more shady
grow
on
roof/shoot Plant hormones Geotropism by planl, as
a turing or
Crowth of has I distinct movement
growth
-
a
stages :
1 all division at near tip
Auxins Indole acetic acid (EAA) substances that control different Roots show positive geotropism + stems show negative
end
important
-
e
.
g many
-
.
georopism
aspeds of plant growth including hopisms differentation
#
,
tissues
of
+ abscission (leaf + Smit fall)
-
has main
↳
synthesised in
young roof cells at his / Experiments
I
1 Diffuses int
elongating region + attaches t recuples on
·
↓
in he cell wall he sensia
in
region
suggest M
spaces is
-
Result
elongate
some of the bonds between microfibrils in the cellmse walls --
easier to shekh by the hugar of the cells
-
can also increase rate of hunscription in cells + speed up
protein synthesis
win
control bending of rooks
7
-
can
1 .
steps
Cells in
in
lip
phototropism
of produce EAA which is hansported
shoot
down t shoet
,
↳
num sugge ratheromon
is
down shoot via diffusion shaded side
2 . IAA
initially hansported evenly it moves shaded :·
as
side
Light of EAA from light >
-
.
3 causes movement
distribution of homone
7
producing uneven
side than light side
on shaded
bending-gone e
builds
light
2 Creater soneEIAA up
no
.
5. == cells on shaded side elongate more
use is dus to
6 .
shaded side elongates faster than light side i. short hip bends unequal distribution of homone
kwards In light
geotropism
I
in
steps the roo
IAA which is hansported along
1. Cells in
lip of roof produce ,
shows
. ZAA
2 is initially hansored to all sides of the roo phototropic response
side to te lower results ham distribution of
of IAA from th upper uneven
3 Gravity influences the movement
.
roo
me amountof chemical dinsa
1
side of thanHe
the lover side of the voor
4. A conc IAA builds up on
greater
upper
sich
of root cells + the conced IAA
. As IAA inhibite the elongation
is a
greater
5
less than th upper side
on the lower side :
My elongah
6 .
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