Plant hormones
and Review of
“P” words and
Review of
Animal
Hormone Paris
Chemicals that make up
hormones
 Plant:

Gases…why?
 Animal:


Proteins/small peptides
Steroids…what is the difference about the
signaling mechanism
Light can signal hormone
production in plants
Compare to animal hormone
signaling mechanisms
Plant hormones to know







Gibberlins
Cytokinins
Ethylene
Abscisic acid
Auxins
As we define this in the next few pages, think
about how a multiple choice question could
get at your understanding.
What if a plant has too much or too little?
Gibberelins
 Promote
stem elongation
 Which plant is a mutant for gibberellic
acid production?
Cytokinins
 Promote
cell division and differentiation
 Why would cytokinins suppress aging?
Ethylene
 Induces
ripening
leaf abscission and promotes fruit
Abscisic acid
 Inhibits
leaf abscission and promotes bud
and seed dormancy.
 Why might these two processes be
controlled by the same hormone?
Auxins
 Promotes
plant growth and phototropism
 How does this experiment show the
activity of auxin?
What hormones might be
involved in germination?
How?
The terrible plant p’s
 Phototropism
 Photoperiodism
 Photorespiration
 Photosystem
 Phytochrome
 Just
in case the college board puts many
of these in a multiple choice!
Tropisms=“movement” in
plants
 Phototropism=light
 Gravitotropism=gravity
 Thigmotropism=touch
 What
do each of these mean? What
would a mutant plant look like?
Photoperiodism and
phytochromes
 The
amount of light triggers reproduction
in plants (photoperiodism!).
 Phytochromes are the receptors that
respond to light.


Short-day plants: light receptor inhibits
flowering.
Long-day plants: light receptor induces
flowering.
What could be an advantage
of being a short-day plant?
Photosystems and
Photorespiration
 Photosystems=light
reactions=good!!!
 Review:


Cyclic=which photosystem(s) and what is
the key product?
Noncyclic=which photosystem(s) and what
is the key product?
Photorespiration
 Calvin
cycle gets O2…bad!!! Rubisco
 Adaptations: CAM/C4

Pep carboxylase
 Temporal?
 Structural?
Bundle sheath
How about animals!
 Example
of hormones from the brain
controlling hormones produced at glands
in the body:


TRH/TSH/T3 & T4
FSH/LH and their targets in males and
females
 Two


feedback loops to know:
Insulin/Glucagon
Calcitonin/PTH
Group quick
presentation…find one picture
that best represents the
hormone system
 What
is the gland that produces each
hormone?
 What are the main targets of each
hormone?
 Are they steriod or protein hormones?
 How does feedback work for the system
you studied?
RAAS and ADH
 Both
control water balance
 ADH:



Produced in the hypothalamus
Acts on the nephron to increase reuptake
of water back into the body
Raises blood volume.
 RAAS:


Kidney and adrenal glands
Contstricts arteries to increase blood
pressure and increases water reabsorption
Positive
Feedback
 Oxytocin=labor
and milk production in
placentals
 Why is positive feedback necessary here?
Where are hormones
from?
 The
ones from organs general have the
organs in the name or we’ve talked
about them!
 Most of the rest come from the anterior
pituitary!!!