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

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

1. Photochemistry 2. Heat 3. Fluorescence

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.

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)

Gibberellin

Promotes fruit production without seeds

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. 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

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

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

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

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

particle and wave

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.

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.

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

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.

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

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

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.

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

Parenchyma

alive at maturity; may be involved in photosynthesis

Collenchyma

alive at maturity; often found in growing shoots