Final Exam Flashcards
Plant Hormones
- 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)
5 classic hormones
- Auxin
- Gibberellin
- Cytokinin
- Ethylene
- Abscisic acid
Auxin
- First plant hormone discovered
- Most common auxin is the indole acetic acid (IAA)
Auxin regulates:
- 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
3 Types of tropic responses (positive or negative types)
- 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)
Gibberellin Hormone (GA)
- 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
Cytokines Hormones
- 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
Ethylene Hormone
- Plants make this hydrocarbon gas: it induces leaf abscission (leafs falling)
- Promotes fruit ripening in climacteric fruit
Abscisic Acid Hormone
- Water stress hormone to help plants in drought-like situations
- Cause stomata to close
- Involved in inhibiting seed germination and promotes seed dormancy
Primary Metabolites
ATP, hormones, and other signal compounds. Things that a plant cannot live without
Secondary Metabolites
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)
3 Metabolites
- Alkaloids
- Terpenes
- Phenolics
Alkaloids
- 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
Terpene group
- 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
Phenolics group
- 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.
Cannabinoid groups
All second metabolites; over 90 kinds of cannabinoids; made by the plant Cannabis; cannabinoids are made in the glandular trichomes ( anti-herbivory and excess of UV light)
Two main types of cannabinoids
- THC: delta 9 tetrahydro-cannabidiolic acid (will get you high)
- CBD: cannabidiodic acid (will not get you high)
- Both bind to endo-cannabinoid receptors (CB1 and CB2 ) that are found in the CNS, but no receptors in th ebrain stem
- 2 ligands or endocannabinoids that they bind to are : Anandamide and 2- arachdonylglycerol
Genetic Engineering
GMO 1 - selective breeding
GMO 2 hybridization (mules x donkeys) crossing 2 species
GMO 3 mutagenesis through chemical or radiation
GMO 4 modern process of genetic engineering
Advantages : quick ad very specific
How to make a trans- genetic plant
- Isolate gene of interest
- Construct recombinant DNA molecule
- Put rDNA into bacteria cells
- Put rDNA into plant cells
- Assess trans-genetic gene
Make a spicy tomato
- Isolate gene of interest ( capsium synthase) via restriction enzymes (proteins that cut DNA at sequence specific sites); attached by hydrogen bonds
Ex: ATGTTC (DNA STRAND) TACAAG (complimentary DNA STRAND)
Stair step cut = AT||||GTTC TACA|||||AG
AT….GTTC
TACA……AG - Separate DNA by gel electrophoresis (charge of -)
Long DNA on top short DNA on the bottom - Create rDNA using gene of interest (capsaicin) and vector (plasmid)
a. Plasmids: in bacteria cell, small, numerous - Insert rNDA into bacterial cell (E. coli) through genetic transformation via heat shock
Select for transformed cells by growing on Ampicillin (grow the bacteria cells) - insert rDNA into the plant cell
2 options: - Biolistic (“gene gun”)
- Agrobacterium tumefaciens (soil bacteria; called “crown gall disease”)
- confirm that transgenesis plant (make sure its completed the objective-spicy plant) by taking DNA and through the process of PCR make sure genes are in the plant or test the fruit once plant has matured
Selective Marker
- Allows the cells that contain the plasmid to be in the presence of AMPR (Ampicillin)
1. Circular plasmid with selective marker, AMPR (Ampicillin) , ECR1 the restriction enzyme cuts right through the ECR1
2. This creates two linear strands. Both complimentary of one another then they hydrogen bond together
3. DNA ligase (enzyme) comes in to repair the phosphodiester bond
Single chromosome
- Centromere and telomeres don’t have any coding sequence (“silent regents”) and no active transcription is going on; If rDNA is found in these two regions it wont be expressed
- Telomeres: function in preventing erosion of genetic material during mitosis. (telomeres get shorter after each round of division)
- Centromeres: function for mitosis
Plant callus:
Will have SAM coming off of it (shoots). If you cut off the stems and put them in a dish and it will grow roots. Next, put plant in dirt.
GE crops on the market:
(1) Corn (2) soybean (3) cotton (4) canola (5) squash (6) papaya (7) apple (8) potato (9) sugar beets (10) alfalfa
• First GE crop (Flavr Savr tomato) was made In 1994. They decreased the expression of gene called polygalacturonate.
• First successful GE crop (BT Corn= Bacillus thoracentesis, causes lysis in caterpillars) in 1995. Spore-forming bacteria (BT example of a Genetically modified plant that benefits farmers)
Parasporoal Crystal (protein):
causes lysis in insects (caterpillars)
Ht Soybean
(herbicide tolerant) modified to live in the presence of herbicide; called Round Up Ready (chemical name: glyphosate) Benefits: 1. Low toxicity 2. Binds tightly to soil 3. Short half life
Golden rice
Designed to help the consumer; genetically modified to use beta-carotene that converts to Vitamin A for developing countries with a lack of vit A.
Papaya
devastated by the Papaya ringspot virus (PRSV Virus); uses gene silencing (or RNAI)- RNA interference: cells way of defending itself; viral coat protein gene and converted it to special recombinant DNA called hair pin RNA.
- to do RNAI: produce inververted repeats. RNA will hydrogen bond to complimentary DNA sequences
Artic Apple
Developed to have decreased levels of polyphenol oxidase
Innate Potato
Benefit the consumers health; decrease browning (asparagine) decrease acrylamide (when exposed to high temp)
Traditional vaccines
(Live chicken eggs make vaccines)
1. Alternated vaccine
“alive” viral particle that has been mutated to be non-pathogenic.
2. Inactive vaccine:
“dead” virus that is still pathogenic
• Instead of making a vaccine out of a viral particle, you create a subunit vaccine (Create a GE plant that makes the viral proteins)
Vaccines can be made from a plant’s chloroplasts (chloroplast GE or “chloroplast transformation”); easy to transform the chloroplast, high gene copy, engages in post-translation modification (can get a fully functioning protein from this engineering), materially inherited mitochondria
Biofuels
Majority of our fuels are fossil fuels (made out of hydrocarbons) Types: (1) oil a. for transportation (2) coal a. for electricity b. problems: when burns you get toxic ash, finite resource (3) natural gas a. for electricity and cars
Issues with biofuels
-methane (CH4) burns and you get energy, but CO2 is generated (CO2 increases, and greenhouse effects increases, causes climate change)
-Carbon cycle: movement of carbon through the ecosystem
CO2 (taken up by plants through photosynthesis, plants make carbs)
- plants/animals metabolizes these carbs through cellular respiration, the bi product is CO2) net accumulation of CO2 is 0.
Environmental damage:
oil spills
sustainable (renewable) energy sources: (1) nuclear-finite resource, no CO2 released and get electricity as result (2) wind-turbine, costly, huge, environmental damage, (3) hydroelectric (water/dam)-no CO2 released, problem-thermo pollution (4) geothermal- no CO2 released, minimizes environmental damage, not a lot of space (5) landfill-gass (methane harvested), CO2 released (6) Solar-coastly, no CO2 release
ALL are used to generate electricity!!
Biofuels (using plants):
- ethanol (CARBON NEUTRAL-C in = C out) requires a lot of water (ethanol production)
a. Feed stock (starch) Way 1: starch (glucose polymer) is starting material —amylase–> simple sugar yeast —fermentation–>ethanol, CO2
i. corn is not a good option for making ethanol
b. Feed stock (cellulose) Way 2: cellulose (glucose polymer) —cellulase-> simple sugar —yeast–> ethanol - biodiesel
a. type of hydrocarbons (similar to petroleum)
b. all oil comes from seeds (lots of input to grow)
c. Move to using algae for biodiesel fuel
Horizontal gene transfer
one unrelated organism to another
Vertical gene transfer
from mom to offspring
