ALL QUESTIONS

List three requirements for a nutrient to be considered an "essential mineral element" for plant growth.

1. A given nutrient must be necessary for growth and reproduction 2. The function of the element cannot be replaced by another mineral element 3. The element must be directly involved in plant metabolism

Briefly explain two ways that mycorrhizal fungi benefit plants.

1. Ectomycorrhiza fungi help transform/fix nitrogen into a useable and beneficial form for the plant (ex. nitrate, amino acids), giving the plant access to more nutrients. 2. Endomycorrhiza fungi, specifically arbuscular mycorrhiza, helps transform/fix phosphorus into a useable and benefitial form for the plant to incoporate (ex. phospholipid bilayer, ATP, phosphate backbone of DNA/RNA).

What are the requirements for an element to be considered "essential" for plant growth?

1. Element must be involved in the development and reproduction of the plant 2. The function of an essential element cannot be replaced by another element 3. Element must be involved in the plant's metabolism

What are the three possible fates of energy absorbed by chlorophyll molecules?

1. Photochemistry 2. Heat 3. Fluorescence

What are the 3 fates of the energy found in a photon absorbed by a chlorophyll molecule?

1. Photochemistry 2. Heat 3. Fluoresence

Briefly explain two reasons why altered flowering time could negatively affect plant fitness.

1. Plants cannot reproduce and transfer their genes to the next generation if they do not flower at a specific time 2. If plants repeatedly flower at the wrong time, they could die or have lasting damage

List two functions of secondary metabolites in plants.

1. Protect against herbivores and pathogens 2. Attract pollinators and seed-dispensers

In C3 photosynthesis, what are the 3 phases of the Calvin-Benson cycle?

1. carbon fixation 2. triose-p production 3. regeneration of RuBP

Match the expected flowering phenotypes with the functional floral organ identity gene combinations below. A & B & C B & C A & C A & B

A & B & C - all flower structures present B & C - carpels and stamens present A & C - sepals and carpels present A & B - sepals and petals present

Design and describe a plant that has two constitutive defense mechanisms and one active defense mechanism. Be sure to include what the purpose of each mechanism is in your answer.

A constitutive defense mechanism is one that is passive or always on. For example, antimicrobial proteins (1) can fight off and kill harmful pathogens that enter the plant. Pre-formed inhibitors (2) can hault the production of certain pathways and resources and provide energy elsewhere depending on the conditions that the plant is facing. An active defense mechanism is one that is inducible and can be turned on/off. Signal receptors (1), for example can sense environmental stimuli - such as drought - and activate a signal transduction pathway that can close the stomata to reduce water loss.

Match the following plant cell types with the plant tissue system that they are associated with. Parenchyma Sieve tube members Chlorenchyma Guard cell Ground Vascular Dermal

Parenchyma - ground Sieve tube members - vascular Chlorenchyma - ground Guard cell - dermal

Gibberellin

Promotes fruit production without seeds

List the three types of tissue systems found in plants and one example of each.

The 3 types of tissue systems are: 1) Dermal Tissue, 2) Ground Tissue, 3) Vascular Tissue 1) Dermal - guard cells 2) Ground - parenchyma cells 3) Vascular - phloem - companion cells

Order the steps of the long day floral signaling pathway of Arabidopsis thaliana

The plant experiences a photoperiod where the light period is longer than the dark period. Clock genes promote the expression of the gene CO FT is transcribed and the mRNA is transported from the leaves to the meristem where it is translated into a protein. Expression of the meristem identity genes increases. The shoot apical meristem begins producing floral structures instead of vegetative structures.

The final electron acceptor in the light reactions is... a. ADP b. NADP+ c. H2O d. Ferredoxin

b. NADP+

The final electron acceptor in the light reactions is... a. ADP b. NADP+ c. NAD+ d. Ferrodoxin

b. NADP+

Which of the following enzymes are involved in C3, C4 and CAM photosynthesis? a. PEP carboxylase b. Rubisco c. Both are involved in all three

b. Rubisco

The ability for soils to retain mineral nutrients via negatively charged components of the soil is known as... a. The tension-cohesion theory b. The cation exchange capacity c. The acid-growth hypothesis d. None of the above

b. The cation exchange capacity

In the water conducting cells of the xylem, the water potential is determined by... a. The solute potential only b. The pressure potential only c. Both the pressure potential and solute potential

b. The pressure potential only

Where does the Calvin Benson cycle occur in C4 plants? a. mesophyll cells b. bundle sheath cells c. cytoplasm d. guard cells

b. bundle sheath cells

A plant growing in a location is proof that the plant is growing to its maximum potential in that location. a. true b. false

b. false

The process of a seed beginning to grow after a period of dormancy is known as... a. emergence b. germination c. etiolation d. none of these are correct

b. germination

The growth of an actively growing shoot tip toward light is known as... a. thigmotropism. b. phototropism. c. gravitropism. d. None of the above

b. phototropism

The source of energy for water to move through a plant comes is... a. the solute potential in the soil b. the sun c. the pressure potential in the xylem tissue d. adhesion

b. the sun

Which of the following is not produced in the C3 photosynthetic pathway? a. ATP b. NADPH c. Malate (malic acid) d. PGA

c. Malate (malic acid)

Which of the following plant cell structure(s) is/are found in all plant cells? a. Plasmodesmata b. Vacuole c. Primacy cell wall d. All of these are found in all plant cells

c. Primacy cell wall

In the Calvin-Benson cycle, the fixation of carbon is catalyzed by... a. Phosphoenolpyruvate carboxylase b. Ribulose 1,5 bisphosphate c. Ribulose 1,5 bisphosphate carboxylase oxygenase d. ATP Synthase

c. Ribulose 1,5 bisphosphate carboxylase oxygenase

In the nitrogen cycle, the largest pool of nitrogen is found where? a. Soil b. Living organisms c. The atmosphere d. Oceans

c. The atmosphere

Which of the following environmental parameters is the best predictor of ecosystem productivity at the global scale? a. total nitrogen availability b. total phosphorus availability c. evaoptranspiration d. daylength

c. evaoptranspiration

In C4 photosynthesis, the initial fixation of carbon dioxide into an organic molecule occurs in... a. the stroma of chloroplasts in the meshophyll cells. b. in cytoplasm of the bundle sheath cells. c. in the cytoplasm of mesophyll cells. d. the stroma of the chloroplast of bundle sheath cells

c. in the cytoplasm of mesophyll cells

In a tracheid cell what factors below are involved in determining the cell's water potential? a. solute potential b. matrix potential c. pressure potential d. both pressure and solute potential

c. pressure potential

Which of the following is not considered a founder crop? a. chickpeas b. barley c. soybean d. pea

c. soybean

Cytokinin

can be used to produce new shoots or new roots from callus tissue.

Which of the following are involved in energy flow through ecosystems? a. the conservation of energy b. the conservation of matter c. entropy d. all of these are involved in energy flow through ecosystems

d. all of these are involved in energy flow through ecosystems

Which of the following is not considered a macronutrient for plants? a. calcium b. magnesium c. potassium d. copper

d. copper

Tracheid

dead at maturity; involved in transport; secondary cell wall

Fiber

dead at maturity; thick secondary cell wall; involved in support

A small organic molecule that is active in low concentrations and has its activity either where produced or in another portion of the plant body is known as a

hormone

Light can behave as both a _____ and a _____

particle and wave

Light is unique in the universe because it behaves as both a _______ and _______

particle and wave

Water moves through the plant via the ______ tissue and sugars move through the plant via the _______ tissue

xylem and phloem

Briefly describe three benefits and three negatives of modern agriculture and why they are either helpful or deleterious. 2 sentences max for each.

Benefits: 1. Less labor - more mechanization of farming means less physical labor for farmers and workers, less injuries 2. Availability to produce all year long - patrons can buy fruits and vegetables no matter the season, convenience, value added to the market 3. Technology - development of machinery has increased crop yield, able to feed more people faster Negatives: 1. Monopolies / economic power - certain companies have developed strict regulations, making it much harder for small farms to survive (ex. Monsanto forcing farmers to only buy their GM seeds, and then suing if they re-use seeds) 2. Environmental concerns - heavy use of insecticides and herbicides can get into our water systems, harm to animals and humans 3. Human health risks - mass production on mega-farms is somewhat unregulated, as we saw by the documentary - it's hard to know exactly what is in our food and whether it will cause harm to humans (especially with the rise of GMOs)

Auxin

Can be used as an effective herbicide on dicot plants.

In the soil-plant-atmosphere continuum, water molecules are connected together via hydrogen bonds that result in a phenomenon known as,

Cohesion

Briefly define each of the following terms in the context of plant physiological ecology "acclimation" and "adaptation". Also, provide an example of each.

Correct Acclimation is a change in phsysiology or development in response to a stressor or change in the environment. For example, if there is a drought, a plant may grow deeper roots to acclimate to the new environment by accessing water deeper in the Earth. Acclimation occurs over a single generation and does not involve any genetic changes. Adaptation, on the other hand, occurs over many generations and does involve genetic changes over time. For example, spring wildflowers have adapted their phsyiology and processes to bloom only in the spring under optimal temperature/conditions. Plants that have adapted this physiology will continue to live and thrive each spring, and evolve to be the dominant species. Adaptation is linked to evolution, which happens at the population level instead of the individual level.

Briefly explain the "Hormone Balance Theory" of seed dormancy/germination. Be sure to include a brief definition of seed dormancy and seed germination as well as a description of the role that gibberellic acid and abscisic acid plays in the theory

Correct Seed dormancy is when a plant remains dormant (few enzymatic and physiological processes, little plant growth). Seed germination is when the seed is broken by a root or shoot and plant growth follows. ABA (abscisic acid) induces dormancy, and inhibits seed germination, while GA (gibberellins) induces seed germination, and inhibits dormancy. These two hormones have opposing effects and regulate or balance dormancy and germination depending on the environment. For example, if there is optimal temperature, sunlight, and water, the plant will synthesize GA and degrade ABA so that the plant can germinate and grow in such ideal conditions. Conversely, if there is drought or flooding, the plant will synthesize ABA and degrade GA, which will induce a dormant state until the environmental conditions are more favorable. Additionally, the DELLA proteins communicate with one another through crosstalk and with other hormones.

The tallest tree on Earth is called Hyperion and it is over 115 meters tall. Explain how water moves from the soil to the atmosphere through Hyperion and why it is unlikely that any trees will grow larger than Hyperion in the future. Be sure to include what is governing water movement through each step that you discuss and the forces that are involved in the process.

Correct Water always moves from areas of less negative to more negative water potential. Thus, the water moves from the soil (where the water potential is the least negative and the pressure is the strongest), to the atmosphere (where the water potential is the most negative and pressure is the weakest). Starting in the soil, the water will be absorbed through roots/root hairs and pushed up to the tracheids and vessel elements, which make up the xylem in the stem. The xylem functions like a straw -- as pressure builds, it will force water all the way up the stem. This process is known as the tension-cohesion theory. Due to water's polarity of partial + and - charges, water can adhere to others and cohere with itself. As water accumulates, molecules will attach to one another, then tension and pressure will build. The stem of the Hyperion tree is presumably extremely tall, and thus requires a massive amount of pressure and energy (which comes from sunlight) for the water to reach the leaves. At the leaves, the water may be evaporated into the atmosphere. Although water abundance and plant productivity are directly related, eventually there will be another limiting factor that inhibits the plant from growing any further (curve will plateau like in the A-Ci curve). I think this concept can be applied to the Hyperion -- this tree has probably exhausted all of the water and other nutrients to grow to that height, and it is unlikely that there would be any tree that grows larger than 115 meters.

Put the steps of a generic signal transduction pathway in order from beginning to end.

Environmental or endogenous signal Reception of signal by receptor Signal transduction Signal transmission Response

Briefly explain how creating a GMO crop is different from traditional crop breeding.

GMO crops are genetically modified, which is a process of directed evolution. Sometimes, genes from one species are transferred to another species. For example, transferring BT toxin from bacteria to corn so that it can produce its own insecticide. Traditional crop breeding will breed naturally occurring crop variants to produce the best crop -- usually one that is the most symmetrical, and thus will sell best at market. In short, GMO crops contain some sort of unnatural, genetic engineering, while traditional crop breeding takes advantage of evolution and naturally occurring variations.

______ promotes seeds to begin growing after a period of dormancy maintained by _______

Gibberellin (GA) Abscisic acid (ABA)

A forest in West Virginia that has clay soils is losing nutrients (both cations and anions) at a high rate after years of acid precipitation. Explain the soil processes that have likely led to this nutrient loss.

In order to gain nutrients from the soil, plants rely on the cation exchange principle which is when protons (H+) dissociate cations from highly negative organic matter in the soil such as clay. Once cations - such as K, Ca, etc - are free, the roots absorb them as nutrients for the plant. Overtime, acid precipitation will disrupt the proton concentration gradient, inhibit the ability of cation dissociation, and thus lead to nutrient loss. Additionally, since acid precipitation is presumably making the soil more acidic and increasing the concentration of protons, some of these positive protons may associate with negative anion nutrients as well and disrupting the exchange of cation nutrients.

Ethylene

Involved in fruit ripening.

absciscic acid

Involved in stomatal closure

Choose one of the two symbiotic relationships that we discussed that help plants gain nutrients. Provide what each member of the symbiosis receives from the other and identify the kind of organism the second group consists of.

Mycorrhizae is a fungi that creates a symbiotic relationship with plants. The mycorrhizae fungi recieves a carbon source of energy (glucose, sucrose) from the plant, and is actually an obligate symbiont, meaning that it cannot survive without the plant. On the other hand, the plant receives nitrogen fixation and gains access to nutrients from the mycorrhizae fungi.

Given what you know about photosynthesis, develop a hypothesis about how rising atmospheric carbon dioxide will likely impact the abundance of C3 and C4 plants in an ecosystem where C4 and C3 plants are found in equal abundance today. Be sure to include a description of the biochemistry and appropriate terminology from A-Ci curves that supports your hypothesis.

Rising atmospheric carbon dioxide will likely increase the abundance of C3 plants. This is because of 2 primary factors: 1) The biochemistry of the dark reaction and 2) The competitive inhibition of Rubisco. First, the biochemistry of the dark reaction in C3 plants is more entergetically efficient -- C4 plants have an extra biochemical step. In C3 photosynthesis, CO2 is immediately fixed with RuBp (catalyzed by rubisco) into PGA, then reduced to triose-P, which is then phosphorylated to regenreate RuBp. This is more entergetically efficient than C4, which fixes CO2 with PEP (catalyzed by PEP carboxylase) into oxaloacetate, which is then transformed into malate and asparatate, which then need to be broken down again to harness energy. Second, CO2 and O2 compete for 1 substrate -- rubisco. If there is more CO2 in the atmosphere, it will continually out-compete oxygen and lead to C3 photosynthesis.

Choose one of the major plant organs and list at least two functions that it carries out for the plant.

Root Functions: 1. Absorb water and nutrients 2. Offer support and anchorage for the plant

Match the secondary metabolite with their synthesis pathway. Each pair only has one correct answer. Terpenes Nitrogen containing secondary compounds Phenolic compounds

Terpenes - mevalonic acid pathway Nitrogen containing secondary compounds - shikimic acid pathway Phenolic compounds - malonic acid pathway

Briefly explain why evolution has not resulted in all plants being able to establish symbiotic relationships with nitrogen fixing bacteria. (3-5 sentences)

The symbiosis between nitrogen fixing bacteria and plants is an ancient mutualistic relationship -- the bacteria transform nitrogen into a useable form for the plant, while the plant provides a carbon energy source for the bacteria to grow. However, not all plants have established this relationship because it requries a very large amount of energy on both ends of the relationship. First, the plant must have expendable carbon (glucose, sucrose) to give the bacteria so that it can grow. Nitrogen fixation requires a massive amount of energy because the N triple bond N is extremely strong and hard to break. Thus, the bacteria must also be expending a lot of energy to provide useable nitrogen sources to the plant. About 20% of the plant's total energy goes to nitrogen assimilation! Therefore, if a plant is in a stressed environment with sub-optimal conditions, it may not have extra carbon sources to provide the bacteria, and this relationship would not be established.

Gross primary productivity

Total amount of carbon fixed in an ecosystem by primary producers..

Net primary productivity

Total amount of carbon remaining in an ecosystem after the loss of carbon to autotrophic respiration.

Net ecosystem productivity

Total amount of carbon stored in an ecosystem after all respiratory losses.

Outline a basic food web in any ecosystem of your choosing. Be sure to include an example of: primary producers, primary consumers, and a secondary consumer in your ecosystem.

Waiting for grade Primary producer: photosynthetic phytoplankton in the ocean (autotrophic - harness energy from the sun and photosynthesis) Primary consumer: shrimp (heterotrophic - harness energy from eating the phytoplankton) Secondary consumer: whale (heterotrophic - harness energy from eating large amounts of shrimp)

Which of the following is not involved in C3 photosynthesis? a. Pyruvate b. Rubisco c. CO2 d. Water

a. Pyruvate

In a plant that is actively transpiring the lowest water potential value will be found in... a. The leaves b. The stem c. The roots

a. The leaves

Norman Borlaug was the first plant scientist to win the Nobel Peace Prize. a. True b. False

a. True

Water may travel across the root cortex via the apoplasm of cells until it reaches the Casparian strip. a. True b. False

a. True

A soil that is nearly equal parts clay, loam and sand would be classified as... a. a loam soil b. a clay soil c. a sand soil

a. a loam soil

Some plants lose their leaves every year during an annually occurring drought. This would be an example of a plant... a. adaptation b. acclimation

a. adaptation

In the soil plant atmosphere continuum, which portion should have the highest water potential if water is moving through the system? a. soil b. plant c. atmosphere d. they are all equal

a. soil

During the elongation of plant cell walls, the protein expansin is activated when... a. the pH of the apoplastic space becomes lower. b. the pH of the apoplastic space becomes higher. c. CECA proteins extrude new cellulose fibers. d. water enters the cell undergoing elongation.

a. the pH of the apoplastic space becomes lower.

Adhesion and cohesion of water molecules is a result of what? a. the polarity of water molecules b. the pull of gravity c. solutes dissolved in water d. all of the above are correct

a. the polarity of water molecules

A tertiary consumer may harness its energy from... a. the sun b. only secondary consumers c. only primary producers d. both primary producers and all types of consumers

a. the sun

The area where primary growth of a plant occurs is known as... a.The apical meristem b. The vascular cambium c. The cork cambium

a.The apical meristem

Parenchyma

alive at maturity; may be involved in photosynthesis

Collenchyma

alive at maturity; often found in growing shoots