Exam 2 Flashcards
What are animals uses for toxins?
Mainly to capture prey
(Some for defense)
Ex. Wasps, snakes, spiders, scorpions, lizards, jellyfish
What are plants uses for toxins?
-Mainly for defense
(Some for offense)
-Plants exhibit widest diversity of chemicals
-Provide richest source for human uses
Why use Venom?
- Circumvent prey defense systems
- Take larger prey down
- Take extremely mobile prey down (Paralysis)
Neurotoxins
- Interacts with nerve cells
1. Affects sodium and potassium channels
i. Channels open with nerve impulse
ii. Nerve impulse is movement of NA+/K+
- OR Causes release of neurotransmitters
Cytotoxins
- Destroys many different cell types
- Results in swelling, internal bleeding, lesions
Evolution of Plant Toxins
-Plants use chemicals mainly for defense
Ex. Hogweed- Heracleum and Furocoumarins
- Kids use it as telescope for fun
- Chemicals + Sunlight = Swelling
Plant Toxic Strategies
- Feeding deterrants
- Digestibility reduces
- Truly toxic
Feeding Deterrants
- Tastes Bad
- Capsicum
- Burning taste of peppers
- Produced in the septa odorless, colorless, crystalline-waxy compound hydrophobic
Digestibility reduces
Extra filing with no nutrients
Bind to nutrients in herbivores gut
Truly toxic
- Attempts to kill herbivore
- Fast acting chemicals on physiology
Responses to heat
- Heat destroys cells, releases H+ and lipid byproducts
- Heat can also directly open receptor channel
- Birds lack receptor to heat so they don’t have any ill effects on fruit
Tannins
- Interferes with protein function and absorption
- Saliva Enzyme > Plant Protein > Enzyme Intact > Protein broken up
- Plants taste bad
Nicotine Induced Defense
- Plants has some reserves in roots
- Feeding by insects produce signal of attack
- Nicotine mobilized and up-regulated
- May take several hours - Insect ingests nicotine
What does Nicotine mimic?
Acetylcholine
Examples of human uses for toxins?
- Taxol
- Digitalis
- Caffeine
- High blood pressure
Taxol
- Bark from Pacific Yew Tree
- Anti-cancer drug
High blood pressure
- Venom from Brazilian Pit viper
- Blood pressure drops
Plant Latex
- Milky sap that gels when exposed to air
1. Seals wounds on plant
2. Deter Herbivores
3. Stores food
Vulcanization
- Heating of rubber and sulfur to strengthen rubber
- Rubber becomes harder, less sticky, and resistant to chemical attacks
What makes Earth unique?
Sun energy
Abundant of water
Photosynthesis
Sunlight, CO2, Water, Glucose
-Makes Oxygen
Light vs Dark Reaction
Light
-Conversion of light energy into chemical energy
Dark
-Incorporation of Carbon into sugar
Chloroplast
- Organelle where photosynthesis occurs
- Can have hundreds per cell
Parts of Chloroplast
- Outer Membrane
- Stroma
- Grana
- Thylakoid
Outer Membrane
Surrounds chloroplast
Stroma
- Liquid within chloroplast
- Dark Reaction
Grana
Stack of thylakoids
Thylakoid
- Pigment containing units
- Light Reaction center
- Photosystems
Photosystems
- Assembly of 250-400 pigment molecules
1. Antenna complex - Directs photon to reaction center
2. Reaction center - Uses photon
3. Pigments absorb light - Energy may be dissipated as heat
- May be re-emitted (Fluorescence)
- Energy may be captured in chemical bond
Chlorophyll
The Lollipop
- Ring
- Site of photon absorption - Tail
- Attaches to membrane
Chlorophyll Reaction Center
- Protein complex at center of photosystem
- Light energy liberates electrons
- Electrons captured and used for work
Photosystems in plants
Photosystem II
- Absorbs light at 680 nanometers
- Supplies electrons for photosystem I
Photosystem I
- Absorbs light at 700 nanometers
- Supplies electrons for sugar building
How do photosystems recharge?
- PS II gets electrons from water
- H+ atoms forms ATP (energy)
Photosynthesis wrap-up
- Capture Light energy
- Splitting of water into O+ and H+
- Production of ATP molecules
Solar Power Types
- Photovoltaics
- Sunlight > Energy - Solar Thermal
- Sunlight > Heat - Passive Solar
- Heating through architectural design
Photovoltaic cell
- Sunlight > Energy
1. N-Type Layer of Silicon - Phosphorus atoms added
2. P-Type Layer of Silicon - Boron atoms added
Problems with Photovoltaic
- Energy gap problem
- only small part of light spectrum is used
- Multi-Junction cells
- Stack of cells with different semiconductors - Absorbing and concentrating light
- Glass coated with organic dye
Solar Thermal
- Sunlight > Heat
1. Water usually used as medium for heat storage
2. Mostly used for residential heating
3. Steam generation applications being tested
Solar Thermal Example
- Direct system
- Active indirect system
- Flat Plate Collector
- Solar Evacuated tubes
- Solar Power Plants
- Passive Solar
- Capturing Light
- Direct System
- Active Indirect system
- Flat Plate Collector
- Solar Evacuated tubes
- Batch collector passive system
- Used in winter
- Closed loop, freeze-protection system - Shower for camping/hiking
- Vacuum between outer and inner tube
- Like Hydro-flask