Final Exam Flashcards
1
Q
Plant Hormones
A
- Signaling compounds (“generals” telling everyone what to do)
- chemically diverse (what they’re made of)
- labile (break down quickly)
- low effective concentration
- promote or inhibit responses (can work synergistically or anti-synergistically)
2
Q
5 classic hormones
A
- Auxin
- Gibberellin
- Cytokinin
- Ethylene
- Abscisic acid
3
Q
Auxin
A
- First plant hormone discovered
- Most common auxin is the indole acetic acid (IAA)
4
Q
Auxin regulates:
A
- Apical dominance
- auxiliary buds contain the SAM (dormant because SAM at the terminal bud isn’t letting them grow because its sending auxin signals from the terminal bud to the auxiliary buds and inhibiting growth.
- terminal bud is the only one growing; it’s the dominant one - Tropic responses (only occurs on the growing tip of plant does not affect mature regions of the plant
- growth response of the SAM/ RAM towards or away from a stimulus (external) - Cell elongation in growing stems
- Auxin is promoting cellular elongation of growing stems; auxin is in high amounts on the shaded side of a coletypile and results in the side with increase of auxin gets elongated and the side without does not.
- Synthetic forms of auxin
- 2,4 D weed killer
- 2,4,5, T US Army
5
Q
3 Types of tropic responses (positive or negative types)
A
- Phototropism: (regulated by auxin)
a. Growth towards/away from light
b. Shoot (positive) root (negative) - Gravitropism
a. Growth towards/away from gravity
b. Shoot (negative) root (positive) - Thigmotropism
a. Growth towards/away from contact with solid object
b. Shoot (positive) root (negative)
6
Q
Gibberellin Hormone (GA)
A
- Main function regulated by GA is internode stem elongation by mechanisms of cell division and cell elongation
- GA can regulate fruit development in some plants
- GA can promote seed germination in grasses only
7
Q
Cytokines Hormones
A
- Come in many types, discovered in coconut milk
- Functions in promoting cells specifically for cell division ( to develop cells without differentiation)
- This hormone can delay leaf senescence
8
Q
Ethylene Hormone
A
- Plants make this hydrocarbon gas: it induces leaf abscission (leafs falling)
- Promotes fruit ripening in climacteric fruit
9
Q
Abscisic Acid Hormone
A
- Water stress hormone to help plants in drought-like situations
- Cause stomata to close
- Involved in inhibiting seed germination and promotes seed dormancy
10
Q
Primary Metabolites
A
ATP, hormones, and other signal compounds. Things that a plant cannot live without
11
Q
Secondary Metabolites
A
Plants do not rely on this as heavily as primary and can still function but not as well. Functions in: attraction, pigments, volatiles (odor/flavor), protection, allelopathy (chemical warfare), symbiotic associations (fungi)
12
Q
3 Metabolites
A
- Alkaloids
- Terpenes
- Phenolics
13
Q
Alkaloids
A
- Nitrogen containing compounds , example morphine (Papauer Somniferous or poppy plant) that acts as anti-herbivory and is made in the fruit of the plant. Morphine is an endorphin analog, it binds to opioid receptors.
1. Capsaicin gives peppers their spiciness, comes from the fruit “capsicum” and is made in the fruit of the plant. Functions as an anti-herbivory and seed dispersal. It binds to sensory neuron (TRPU1) that signal that its hot.
2. Caffeine/theobromine lots of plants make this, main sources: coffea arabica made in the type of alkaloid, camellia sinensis made in the young leaves. Anti-herbivory and allelopathy, activates CNS, cardiac muscles and releases smooth muscles.
3. Theobroma cacao: found in seeds of th plants; similar in affects to caffeine; plants it functions in anti-herbivory, humans it activates CNS, prevent coughs, vasodilator, and heart stimulant
14
Q
Terpene group
A
- Secondary metabolite group; all produced by a common biosynthetic pathway; starting material is always isopentyl pyrophosphate (IPP)
1. Taxol - type of diterpenoid ( 2IPP’s) and found in the Taxus brevifolia plant family (made in the cambium layers- inner bark- functions as protection) Mitotic inhibitor, triggers apoptosis.
2. Monoterpene: made up of methanol (25, 000 metric tons of menthol sold/year. Used for culinary/ flavoring/ anesthetic) The plant species Mentha arvenis produces this for anti-herbivory. Menthol binds to sensory neuron receptor TRPII8
3. Latex - natural rubber. Comes from the tree Hevea brasilliensis. Made in the inner bark.
4. Carotenoids: responsible for B-carotene and lycopene (pigments for attraction) not water soluble
15
Q
Phenolics group
A
- Derived from phenylalanine
1. Contain family of anthocyanin pigments (all water soluble and found in vacuole- function in attraction, protection from light, and antioxidants used in food colorings)
2. Phytoestrogens- isoflavones - Daidzein and Genistein (produced by soybean) soy convert to estrogen-mimics that bind to estrogen receptors.