Term
| How long have homo sapiens been around? |
|
Definition
|
|
Term
| How long have people been farming? |
|
Definition
|
|
Term
| How did people get food before farming? |
|
Definition
|
|
Term
| What evidence do we use to determine when farming began? |
|
Definition
|
|
Term
|
Definition
|
|
Term
| how much of the protein consumed worldwide comes from plants? |
|
Definition
|
|
Term
| What are the two main sources of plant protein intake in humans? |
|
Definition
Legumes (18%)
Cereals (70%) |
|
|
Term
| What countries make up the fertile crescent? |
|
Definition
| Syria, Turkey, Iran, Iraq, Israel, and Jordan |
|
|
Term
| Where was barley first domesticated? |
|
Definition
|
|
Term
| Where was wheat first domesticated? |
|
Definition
|
|
Term
| where were peas first domesticated |
|
Definition
|
|
Term
| Where were apples first domesticated |
|
Definition
|
|
Term
| Where were soybeans first domesticated |
|
Definition
|
|
Term
| Where were citrus fruits first domesticated? |
|
Definition
|
|
Term
| Where was coffee first domesticated? |
|
Definition
|
|
Term
| where were pinapples first domesticated? |
|
Definition
|
|
Term
| Where was cocoa first domesticated |
|
Definition
|
|
Term
| Where were apricots first domesticated? |
|
Definition
|
|
Term
| Where was diploid cotton first domesticated? |
|
Definition
|
|
Term
| Where was triploid cotton first domesticated? |
|
Definition
|
|
Term
| Where were bananas first domesticated? |
|
Definition
|
|
Term
| Where were most spices and herbs domesticated? |
|
Definition
|
|
Term
| Where were grapes first domesticated? |
|
Definition
|
|
Term
| Where was sugarcane first domesticated? |
|
Definition
|
|
Term
| What are the 6 plants that provide more than 80% of the calories humans consume? |
|
Definition
Rice
Wheat
Maise
Potatoes
Sweet Potatoes
Manioc |
|
|
Term
| About how many humans are added to the population each day? |
|
Definition
|
|
Term
| How can we produce more food to stop world hunger? |
|
Definition
| Increase the productivity of the crops we currently have |
|
|
Term
| What is a good way to find new useful plant species? |
|
Definition
| Use ethnobotanical information.(study what plants different cultures use) |
|
|
Term
| How many angiosperm species are there? |
|
Definition
|
|
Term
| What are to ways to preserve genetic diversity in plants? |
|
Definition
Conserve various ecosystems
Create germplasm banks (Repositories for varieties of plants) |
|
|
Term
| What are two new and important crops? |
|
Definition
|
|
Term
| During what geological time period did hominids first evolve? |
|
Definition
|
|
Term
| what 4 genera did hominids evolve through between the common ancestor with chimpanzees and humans? |
|
Definition
Ardipithecus
Australopithecus
Paranthropus
Homo |
|
|
Term
| What parts of the world were hot spots for starting agriculture and domestication? |
|
Definition
| Mesoamerica, south american highlands, Yellow and Yangtze river basins, eastern U.S., the fertile crescent, and new guinea highlands. |
|
|
Term
| Where does fossil evidence suggest corn developed? |
|
Definition
| Tehuacan valley in Mexico. |
|
|
Term
| What kind of evolutionary force drove domestication? |
|
Definition
|
|
Term
| Where was taro first domesticated? |
|
Definition
|
|
Term
|
Definition
| A member of the grass family related to wheat and corn |
|
|
Term
| What part of taro is edible? |
|
Definition
|
|
Term
|
Definition
| An underground stem that is rich in starches |
|
|
Term
| Where were yams first domesticated? |
|
Definition
|
|
Term
| What plant can be used to synthesize contraceptives? |
|
Definition
|
|
Term
| What is the name of the plant that is the ancestor of modern corn? |
|
Definition
|
|
Term
| What is the ear of a teosinte plant like? |
|
Definition
| Consists of 8 kernels with hard seeds |
|
|
Term
| Where and why is casava important? |
|
Definition
| Important in south america because it produces large starchy tubers. |
|
|
Term
| What plant was domesticated in the U.S. and what does it produce? |
|
Definition
| Sunflowers. They produces seeds and oil. |
|
|
Term
| What part of the plant is mace produced from? |
|
Definition
|
|
Term
| What part of the plant is used to make pepper? |
|
Definition
|
|
Term
|
Definition
| They use the ground up seed to make nutmeg |
|
|
Term
| What two spices were domesticated in the new world? |
|
Definition
|
|
Term
| What are the 14 vital crops that are responsible for 80% of calories we consume? |
|
Definition
| wheat, rice, maise, potatoes, sweet potatoes, manioc, sugarcane, sugarbeet, beans, soybeans, barley, sorghum, coconut, and bananas. |
|
|
Term
| How was the jojoba found? |
|
Definition
| Using ethnobotanical information |
|
|
Term
| What is characteristic of the jojoba and what is this used for? |
|
Definition
| Seeds contain 50% wax. This is used to lubricate machines under extreme pressures. It is also used in food additives and cosmetics. |
|
|
Term
| Why is the Amaranth so important? |
|
Definition
| The leaves are edible, and the fruit is tasty and high in protein. |
|
|
Term
| Why is the Solanum cheesmaniae a relative of and why is it important? |
|
Definition
| Solanum cheesmaniae is a relative of the tomato and it tolerates high salinity so it can be grown in overirrigated land and land near the sea. |
|
|
Term
| What is the rosy periwinkle used for? |
|
Definition
| A natural source of drugs that target certain cancers. |
|
|
Term
| What is milkweed used for? |
|
Definition
| The trichomes of the seeds are used to make pillows. |
|
|
Term
| where were the first agricultural settlements found? when were they active? |
|
Definition
| Found in the east, the fertile crescent, and the new world around the same time 11,500 years ago. |
|
|
Term
| Where does the embryo develop? |
|
Definition
|
|
Term
| what is plant embryogenesis? |
|
Definition
| The formation of an embryo from the zygote. |
|
|
Term
| What are the products when the zygote first divides? Comment on the cell sizes. |
|
Definition
| A large basal cell and a smaller terminal cell. |
|
|
Term
| what is the two cell proembryo? |
|
Definition
| The basal cell + the terminal cell |
|
|
Term
| What does the apical cell give rise to? |
|
Definition
|
|
Term
| What does the basal cell give rise to? |
|
Definition
|
|
Term
| What does the suspensor do? |
|
Definition
| Transports nutrients to the embryo |
|
|
Term
| What does the 6 cell proembryo look like? |
|
Definition
| There are 4 elongated suspensor cells and 2 terminal cells |
|
|
Term
| Where does the developing embryo get food? |
|
Definition
| From the mother plant and the endosperm |
|
|
Term
| What is the composition of endosperm? |
|
Definition
|
|
Term
| What is the embryo proper? |
|
Definition
| The embryo proper is the embryo during the globular stage when you can see the different meristems. |
|
|
Term
| Nucellar tissue is another name for... |
|
Definition
|
|
Term
| What happens at the torpedo stage? |
|
Definition
| The suspensor undergoes programmed cell death and detaches the embryo from the mother plant. |
|
|
Term
| How does the embryo of a monocot differe from eudicots? |
|
Definition
| There is no heart stage, instead a notch develops that seperates the cotyledon from the hypocotyl-root axis. |
|
|
Term
| What happens once the embryo is fully developed? |
|
Definition
| The funiculus is no longer needed, so it detaches leaving a scar called the hilum. The ovule also begins dessication (process of drying out), and the integuments harden to become the seed coat. |
|
|
Term
| What is in the pelvis area of the bean seed? |
|
Definition
| The area where the radicle will emerge, the hilum, and the micropyle. |
|
|
Term
| How have mutations helped us understand embryo development? |
|
Definition
| disabling certain genes has cause some things not to develop. This shows us what genes control what phenotypes in embryo development. |
|
|
Term
| How are mutant plants created? |
|
Definition
| They are exposed to a chemical mutagen, then selected based on what they can show. |
|
|
Term
| What makes up the seed coats? |
|
Definition
|
|
Term
| What does the plumule become in a grain? |
|
Definition
|
|
Term
| What is the function of the coleoptile? |
|
Definition
| To protect the scutellum and the young leaves |
|
|
Term
|
Definition
|
|
Term
| What is the middle of the grain embryo called? |
|
Definition
|
|
Term
| What does the coleorhiza do? |
|
Definition
| Provides additional protection for the root cap. |
|
|
Term
| What is the first structure to emerge from the seed during germination? |
|
Definition
|
|
Term
| How much of the whole weight of the seed is water? Why? |
|
Definition
| 5-10 percent. Because being in a desiccated state allows the embryo to stay dormant. |
|
|
Term
| What are the steps in seed germination? |
|
Definition
| imbibition of water - embryo activation - slower water uptake - mobilization of stored food - radicle emergence - est. plant body |
|
|
Term
| what hormone breaks down the endosperm, what produces it, and what causes this structure to produce it? |
|
Definition
| Amylase is produced by alurone. caused by inbibition of water. |
|
|
Term
| what are some examples of epigeal seed germination? |
|
Definition
|
|
Term
| What are some examples of hypogeal seed germination |
|
Definition
|
|
Term
| How long are seeds usually viable? |
|
Definition
|
|
Term
| What is the record for seed dormancy? |
|
Definition
|
|
Term
| How can the embryo stay dormant? |
|
Definition
| it reduces it's metabolism until conditions are right. (Light, water, temperature) |
|
|
Term
| What 3 things cause seed dormancy? |
|
Definition
| Seed is still immature, the seed coat is impermiable to water, not enough oxygen is available. |
|
|
Term
| Why are some seeds dormant? |
|
Definition
| they need the right conditions to grow, or they need to be dispersed to another location first (by animals). |
|
|
Term
| How long ago did the first photosythetic organisms appear? |
|
Definition
|
|
Term
| When did the first water splitting photosynthetic cells arise? |
|
Definition
| About 2.5 billion years ago. |
|
|
Term
| when did aerobic respiration arise and why? |
|
Definition
| about 2 billion years ago owing to the abundance of oxygen in the air due to water splitting photosynthesis producing oxygen. |
|
|
Term
| When did eukaryotic cells arise? |
|
Definition
|
|
Term
| when did the first multicellular life arise? |
|
Definition
| about 1 billion years ago. |
|
|
Term
| give the major events in evolutionary history in order. |
|
Definition
| formation of the earth - formation of the ocean - first prokaryotic cells - first photosynthetic organisms - first h20 splitting photosynthetic organisms - aerobic respiration - eukaryotic cells - multicellular life - vertbrates |
|
|
Term
| during what era did photosynthesis arise? |
|
Definition
|
|
Term
|
Definition
| process that converts solar energy into chemical energy. |
|
|
Term
| what is the equation for photosynthesis? |
|
Definition
| H20 + CO2 + LIGHT ---> C6H1206 + 02 + H20 |
|
|
Term
| What is the respiration equation? |
|
Definition
| C6H1206 + 02 ---> C02 + H20 + ENERGY |
|
|
Term
| what do we get out of the light reaction? |
|
Definition
|
|
Term
| what do we get out of the calvin cycle? |
|
Definition
| carbohydrates (C3H603 - TRIOSE) |
|
|
Term
| What is visible light a tiny part of? |
|
Definition
| The electromagnetic spectrum |
|
|
Term
| what are the structural components of a chlorophyll molecule? |
|
Definition
| A porphyrin ring connected to a long phytol tail. |
|
|
Term
| What is an absorption spectrum? |
|
Definition
| The characteristic spectrum of absorption for each pigment. |
|
|
Term
| what is an action spectrum? |
|
Definition
| a combination of the pigments in a plant that shows what colors are absorbed most by the plant. |
|
|
Term
| what molecules in the plant trap the energy from sunlight? |
|
Definition
| pigments like chlorophyll, xantophylls, caratoids, ect. |
|
|
Term
| in what cellular structures does the energy trapping take place? |
|
Definition
|
|
Term
| what are the antenna pigments? where are they located?? |
|
Definition
| Antenna pigments are pigments that collect all of the energy from sunlight and funnel it to the center of the photosystem. |
|
|
Term
| What is the reaction center? |
|
Definition
| The center of the photosystem. It has 2 special chlorophyll molecules that collect the energy from the antenna pigments. |
|
|
Term
| why are antenna pigments necessary to start the photosynthesis process? |
|
Definition
| Because they only collect a little bit of energy from sunlight, not enough to start photosynthesis. the collected efforts of all the photosystems allow for photosynthesis to take place @ rxn center. |
|
|
Term
| photosystem II is also called |
|
Definition
|
|
Term
| What molecule is the first electron acceptor in PSII? second? third? |
|
Definition
| Pheophyton -> plastoquinone -> Cytochrome B6f complex |
|
|
Term
| How do hydrogens get into the thylakoid lumen? |
|
Definition
| The splitting of H20 puts hydrogens there, but also cytochrome B6f pumps hydrogens into the thyladoid lumen. |
|
|
Term
| name all electron acceptors in light dependent reaction in order. |
|
Definition
| P680 - pheophyton - plastoquinone - b6f - plastocyanin - P700 - mod. chlorophyll a - phylloquinone - iron sulfur proteins - ferrodoxin - flavoprotien - NADP+ reductase |
|
|
Term
| what happens in cyclic electron transport? |
|
Definition
| PSI (P700) - iron sulfur proteins - ferredoxin - B6f - plastocyanin - PSI - (rpt) |
|
|
Term
| what are the differences between cyclic and noncyclic electron transport? (on next exam) |
|
Definition
| Cyclic only produces ATP using only PSI. There is no NADP+ synthase. No water will be split, the electrons are reused by PSI. |
|
|
Term
| How do photosynthesis inhibiting pesticides work? |
|
Definition
| They bind to a protein in the electron transport chain. This blocks the energy transport leading to free radical production in such large amounts that the plant dies. |
|
|
Term
| what happens generally in C3 photosynthesis? |
|
Definition
| CO2 is captured and turned into 3 carbon sugars. |
|
|
Term
| What are the 3 steps of the calvin cycle? (C3) |
|
Definition
1. Carboxylation
2. Reduction
3. Regeneration of 5C RuBP |
|
|
Term
| What is the carboxylation reaction and what facilitates this? |
|
Definition
RuBP + CO2 --> 2PGA
RuBisCO Facilitates. |
|
|
Term
| What is the product of reduction of PGA? |
|
Definition
|
|
Term
| How many PGAL go to regerate the RuBP? |
|
Definition
|
|
Term
| What is the cost of reduction of PGA to PGAL? |
|
Definition
|
|
Term
| What is the cost of regeneration of RuBP? |
|
Definition
|
|
Term
| Write the whole calvin cycle. |
|
Definition
| RuBP + CO2 -RuBisCO-> PGA -3PGA kinase (ATP)-> 1,3-biPGA -PGAL dehydrogenase (NADPH)-> (6)PGAL (5) -ATP-> RuBP (rpt) |
|
|
Term
| write the overall equation for carbon fixation |
|
Definition
| 3CO2 + 9ATP + 6NADPH + 6H+ --> PGAL + 9ADP + 8P + 6NADP+ + 3H20 |
|
|
Term
| by what kind of metabolism does the plant make sugar from PGAL? |
|
Definition
|
|
Term
| what other useful molecules can be created from derivations of calvin cycle compounds? |
|
Definition
| Lipids, Acetyl CoA, Polysaccharides, and Nucleic Acids |
|
|
Term
|
Definition
| Half glucose half fructose. |
|
|
Term
| what sugar is transported in the phloem?? |
|
Definition
|
|
Term
| What does PGAL turn into to be stored? |
|
Definition
|
|
Term
| what cells is sucrose transported to for transport? |
|
Definition
| Mesophyll - bundle sheath cell - phloem parenchyma cell - companion cell - seive tube |
|
|
Term
| how is the sucrose transported from the source to the sink once it is in the phloem? |
|
Definition
| The vessel elements right next to it are full of water and as sucrose is added to the seive tube, the higher concentration of substrate causes osmosis to place more water into the seive tube which forces the sucrose down to the sink (gravity). |
|
|
Term
| why is photorespiration bad? |
|
Definition
| The toxic compound phosphoglycolate is produced and processing it costs ATP and NADPH, and releases CO2. |
|
|
Term
| What organelles does photorespiration require? |
|
Definition
| it involves 3 organelles - the chloroplast, the peroxisome, and the mitochondria. |
|
|
Term
| What is phosphoglycolate eventually turned into? |
|
Definition
| It is turned into PGAL and entered into the calvin cycle. |
|
|
Term
| What anatomical adaptations do plants have to adapt to hot and dry environments? |
|
Definition
| Thick waxy cuticle and bulliform cells to close their leaves. |
|
|
Term
| what are two adaptations to photosynthesis in hot and dry environments? |
|
Definition
| C4 and CAM photosynthesis |
|
|
Term
|
Definition
|
|
Term
| Why is C4 photosynthesis so named? |
|
Definition
| Because PEP (3C) combines with CO2 to form a 4 carbon oxaloacetate in the mesophyll cells |
|
|
Term
| What does the mesophyll cell store the 4C oxaloacetate as? (c4 photosynth) |
|
Definition
|
|
Term
| When the CO2 first enter the mesophyll cell in c4 photosynthesis, what happens? |
|
Definition
| CO2 combines with H20 to form HCO3 which then combines with PEP to form oxaloacetate. |
|
|
Term
| The oxaloacetate in C4 respiration can be turned into 2 things, what are they? |
|
Definition
|
|
Term
| Why does the plant bother doing C4 respiration? |
|
Definition
| There is too much oxygen in the plant because it lives in a hot and dry environment so it can't open its stoma during the day without losing water. To avoid photorespiration it transports malate to the bundle sheath cells then catabolizes the malate to form CO2 which enters the calvin cycle and doesn't form toxic phosphoglycolate. |
|
|
Term
| what sort of electron transport chain does the chlorophyll in the bundle sheath cells do? Why? |
|
Definition
| Cyclic electron transport in the bundle sheath cells because if they did non-cyclic they would create oxygen and ruin the oxygen free environment of the bundle sheath cells. |
|
|
Term
| where is all the RuBisCO in C4 plants? |
|
Definition
|
|
Term
| Why did C4 plants first evole from C3 plants? |
|
Definition
| because 50-60 million years ago there was a decline in atmospheric CO2 and increase in O2 this led to a strong selective advantage for C4 photosynthesis. |
|
|
Term
| T/F C4 plants are more efficient at using nitrogen and water. |
|
Definition
|
|
Term
| Where do C4 plants do best? |
|
Definition
| Hot, nutrient deficient areas. |
|
|
Term
| what are some examples of CAM plants? |
|
Definition
| Cacti succulents and pineapples |
|
|
Term
| How does a CAM plant work generally? |
|
Definition
| it fixes the carbon to a 4 carbon acid during the night then uses that CO2 to do the calvin cycle during the day. |
|
|
Term
| what is different about the C4 leaf anatomy compared to C3? |
|
Definition
| The mesophyll cells are all arranged around the bundle sheath cells, and don't have any chloroplasts. The bundle sheath cells are also thicker. |
|
|
Term
| What two factors increase photosynthetic rate in low concentrations, but too much decreases the photosynthetic rate? |
|
Definition
|
|
Term
| What is the equation for photorespiration? |
|
Definition
| RuBP + O2 --> PGA + Phosphoglycolate |
|
|
Term
| What basic steps happen in the plant to process phosphoglycolate? |
|
Definition
1) In the chloroplast the phosphoglycolate is dephosphorylated and turned into glycolate
2) In the peroxisome the glycolate is oxidized via hydrolysis and turned into glycine
3) In the mitochondria the glycine is turned into serine producing NADH and CO2
4)in the peroxisome the serine is turned into glycerate - uses an NADH
5)In the chloroplast the glycerate is phosphorylated into a phosphoglycerate (PGA) and entered into the calvin cycle |
|
|
Term
| how does the peroxisome deal with the fact that hydrogen peroxide (H2O2) is created during the processing of phosphoglycolate? |
|
Definition
| It uses catalase to convert the H2O2 into water and oxygen. |
|
|
Term
| what is needed to turn serine into glycerate? |
|
Definition
|
|
Term
| how does a thick cuticle help the plant adapt to hot and dry environment? |
|
Definition
1)reflects the solar radiation
2) prevents water loss. |
|
|
Term
| You see a cross section and the plant has large bundle sheath cells. What does this indicate? |
|
Definition
| It operates by C4 photosynthesis |
|
|
Term
| how is oxaloacetate made, where is it made, and in what kind of plant? |
|
Definition
| Oxaloacetate is made from a anabolic reaction of bicarbonate ion (HCO3-) and a phosphoenolpyruvate (PEP) in the mesophyll cells of plants that undergo C4 photosynthesis. |
|
|
Term
| What enzyme facilitates the conversion of PEP to oxaloacetate? |
|
Definition
|
|
Term
| Why is the process of CAM respiration similar to C4? |
|
Definition
| Because Phosphoenolpyruvate and HCO3- still combine to form oxaloacetate at night. the oxaloacetate is then turned into malate and stored in the vacuole for usage during the day. |
|
|
Term
| What can malate be turned into in CAM plants? When does this happen? |
|
Definition
| Malate can be turned into pyruvate (3C) and CO2 which is used in the calvin cycle. |
|
|
Term
| Which process has the highest photosynthetic rate? |
|
Definition
| C4 has the highest photosynthetic rate |
|
|
Term
| Which process has the lowest photosynthetic rate? |
|
Definition
|
|
Term
| What is different about the CAM plant's cells? |
|
Definition
| They have very large vacuoles. |
|
|
Term
| When are the stoma open in C4 and C3 plants? |
|
Definition
| Stoma are open during the day and closed at night when there is no light to do photosynthesis. |
|
|
Term
| What sugar needs to be synthesized for transport in the phloem? |
|
Definition
|
|
Term
| How does the plant break down sugars to obtain energy? |
|
Definition
| Throught the respiration process. |
|
|
Term
| Where is starch accumulated after the calvin cycle? |
|
Definition
|
|
Term
| What is used to start the respiration process in plants? |
|
Definition
|
|
Term
| T/F When a chlorophyll molecule at the reaction center of a photosystem absorbs sufficient energy, it is oxidized by loss of an electron. |
|
Definition
|
|
Term
| The Calvin cycle produces a compound that is used to synthesize other carbohydrates such as sucrose and starch. The name of this compound is: |
|
Definition
| Phosphoglyceraldehyde or Glyceraldehyde 3-phosphate |
|
|
Term
| Photorespiration is favored by.... |
|
Definition
|
|
Term
| Where does oxygen come from? |
|
Definition
| The dissociation of H20 molecules during the light dependent reaction of photosynthesis. |
|
|
Term
| What are the photosynthesis molecules arranged on the periphery of the photosytem called? What are they made of? |
|
Definition
| Antenna molecules. Made of chlorophyll. |
|
|
Term
| Where is the electron transport chain located? This takes place during the ____ of photosynthesis. |
|
Definition
| In the thylakoid membrane. This takes place during the light dependent reactions of photosynthesis. |
|
|
Term
| What is PSII's electron acceptor? |
|
Definition
|
|
Term
| What happens during carboxylation? |
|
Definition
| The Rubisco creates PGA (Phosphoglycerate) from CO2 and Ribulose 1,5-biphosphate. |
|
|
Term
| Photorespiration occurs when rubisco combines with oxygen to produce glycolate. Why is photorespiration is a wasteful process? |
|
Definition
| because energy is used to break down glycolate and CO2 is produced. |
|
|
Term
| n the C4 pathway, what happens to the CO2 formed when malate is decarboxylated in bundle-sheath cells? |
|
Definition
| It enters the calvin cylce |
|
|
Term
| After a chlorophyll molecule is “hit” by a photon, which of the following occur? |
|
Definition
| DOnation of a ectron from chlorophyll to an electron acceptor. |
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Term
| where does carbon fixation take place in C3 photosynthesis? |
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Definition
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Term
| What is the most promising approach to solving the world's food problems? |
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Definition
| Improving the existing crops. |
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Term
| ______ is a particularly salt-tolerant plant that may prove useful in producing salt-tolerant hybrids. |
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Definition
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Term
| Unlike cereals, the seeds of grain amaranths have a high content of: |
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Definition
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Term
| What percentage of available prescription drugs come from plants? |
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Definition
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Term
| T/F Chili peppers originated in the OLD world |
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Definition
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Term
| The result of double fertilization in angiosperms is: |
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Definition
| One zygote and endosperm tissue |
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Term
| In a grass embryo, the coleorhiza encloses the: |
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Definition
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Term
| Is periderm present in the torpedo stage of embryo development? |
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Definition
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Term
| The fruit characteristic of the pea family is a(n): |
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Definition
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Term
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Definition
| A fruit formed from one embryo that is dehiscent along one seam |
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Term
| What is charactaristic of drupes? |
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Definition
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Term
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Definition
| The density of transistors on a microchip will double every 18 months. |
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Term
| What does Elias Greenbaum want to do to create better and more efficient microchips? |
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Definition
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Term
| How small are photosytems? |
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Definition
| a million times smaller than a grain of sand. |
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Term
| What is the first electron acceptor in PSI? |
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Definition
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Term
| how long does the light dependent reaction take? |
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Definition
| a few billionths of a second |
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Term
| What did greenbaum was the most important thing about PSI? What did this remind him of? Why? |
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Definition
| THe most important thing about PSI is that it is structured in such a way that it prevents the electron from going back to photosystem II. This reminded Greenbaum of a semiconducting diode because the electrons can only move in one direction. |
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Term
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Definition
| Converting alternating current (AC) to direct current (DC) |
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Term
| What does a semiconducting diode do? |
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Definition
| It is a rectifier - turns AC to DC. |
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Term
| What are logic gates and how are they made? |
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Definition
| Logic gates are digital switches that carry out electronic calculations. to make one you must connect many semiconducting diodes. |
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Term
| how big are Photosystem's? How much smaller are they than the current smallest semiconducting diode? |
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Definition
| 7 nanometers in diameter. more than 20 times smaller than the current smallest semiconducting diode. |
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Term
| Why cant you just pluck up the photosystems and arrange them to create logic gates? |
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Definition
| Because they are delicately folded proteins that can easily be disrupted. If they are disrupted the reaction center does not work. Also they are in the thylakoid membranes inside of chloroplasts inside of plant cells, getting them out is very hard. |
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Term
| why did greenbaum choose spinach? |
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Definition
| . "Spinach is readily available and has soft, tender leaves - that makes it much easier to extract the reaction centres." |
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Term
| How do they prepare the spinach? What are the challenges with this? |
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Definition
| They blend the spinach with plenty of ice to keep it cold because the enzymes released during blending could break down the reaction centers. |
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Term
| How does greenbaum extract the chloroplasts from the plant cell? |
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Definition
| He crushes up the cells then runs them in a centrifuge to seperate the chloroplasts from the crushed plant matter. |
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Term
| How does greenbaum extract the reaction centers from the chlorophyll? |
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Definition
| He uses a detergent that chisels out the reaction centers which can then be seperated by chromatography. |
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Term
| How did greenbaum make his spinich diode once he had the reaction centers separated? |
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Definition
| He immersed gold plated wafers in a suspended solution of reaction centers then looked at the wafers under a scanning tunnel microscope. |
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Term
| How did greenbaum test his diodes. What problem did he find? What did he do about it? |
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Definition
| He applied a voltage between the microscope tip and the wafers and measured the electrical properties. He found that the reaction centers only worked when they were pointing upwards. He coated the gold plates with mercaptoacetic acid to give them a negative charge. This caused the reaction centers to stand up horizontally. He then treated the gold plate with 2-mercaptoethanol which caused them to stand up vertically. |
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Term
| THe reaction centers can't all be jumbled up to make a diode. How must they be arranged? |
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Definition
| They must all be pointing upwards and they must also be connected to form circuits! |
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Term
| How does greenbaum plan to connect the reaction centers into a circuit? |
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Definition
| our goal is to use carbon nanotubes and organic molecular wires which would transport charge |
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Term
| What property of the reaction centers could be the answer to the problem of how to connect the reaction centers into circuits? |
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Definition
| The reaction centers are slightly positive on each end. If the nanotubules were given a negaive charge they could attach to the biodiodes. |
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Term
| What is a huge problem for the diodes once they are connected and operational? How can they solve this? |
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Definition
| If the diodes are exposed to air the reaction centers oxidize which cause them to stop working. Seal the diodes in oxygen free boxes. |
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Term
| besides being a new semiconducting diode, what other property/function does the diode have? What could this be used to do? |
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Definition
| Each reaction center is essentially a small solar cell. They produce one volt potential when hit with a lazer. The electron leaves one side and go around the circuit. Make computer power supplies that run on sunshine. |
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Term
| junipers and yews are examples of conifers without... |
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Definition
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Term
| leaves in conifers are either ____ or _____. |
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Definition
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