Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
PLS 002 Final Stack
Flashcards to help study for the Final Exam in PLS 002.
| Question | Answer |
|---|---|
| If you double the light intensity received by a leaf, how much does photosynthesis increase? | It increases, but less than doubling. |
| How does leaf anatomy contribute to efficient light penetration within leaves? | The palisade mesophyll help transmit light down to the chloroplasts and the spongy mesophyll at the bottom of the leaf. |
| Where in a root system does most uptake of nutrients and water occur, and why? | Tips of the fine roots because those are the "unexplored" areas where the soil hasn't been depleted yet. |
| What is the causal mechanism of phloem sugar transport? | Sugar is pumped into the phloem at a "source", then osmotic pressure increases, then water potential decreases, then water enters the phloem at the source, then pressure increases, then the pressure difference drives the bulk flow to "sink" tissues. |
| What is meant by "latent heat"? | The energy required to evaporate water. |
| Under what conditions is vapor pressure deficit (VPD) lowest? | Under cool and moist conditions. |
| Under what conditions is vapor pressure deficit (VPD) highest? | Under warm and dry conditions. |
| How do leaf size and wind speed affect leaf temperature? | Smaller leaves are closer to the air temperature than larger leaves. If a leaf is cooler than the air, then it gains heat from the air (it gains heat from the wind) and vice versa. |
| True or false: leaves emit electromagnetic radiation (light), even in darkness. | True, everything emits in the infrared (Stefan-Boltzmann Law). |
| Flow | Movement of something per unit time. |
| Flux | Movement of something per unit time, per unit area. |
| Under what environmental conditions does net CO2 assimilation rate equal respiration rate? | Under dark conditions. |
| What does relative humidity mean? | Vapor pressure as a fraction of its saturating value. |
| What is harvest index? | Yield per total biomass produced. |
| What is an empirical model? | An empirical model is choosing an equation based on how the data looks. |
| What is a mechanistic model? | A mechanistic model is choosing an equation because a more conservative principle predicted that type of equation. |
| What does the Penman-Monteith equation predict? | It predicts evapotranspiration from meteorological conditions. |
| True or false: crop systems models are typically a combination of empirical and mechanistic models. | True. |
| What does radiation use efficiency mean? | The ratio of biomass produced to radiation absorption. |
| What are some of the beneficial uses of viruses in plant science and agriculture? | Vectors for genetic transformation, biocontrol of other pests, and creating chimeras for aesthetic purposes. |
| What is a nodule (in the context of plant-bacterial symbiosis), and what is its function? | It is a structure that grows on the roots of plants and hosts the bacteria that do Nitrogen fixation in legumes and a few other species. |
| What is a mycorrhiza? | A fungal symbiont with roots. |
| What does virulence mean? | Loss of evolutionary fitness to the host. |
| What is normally the most important greenhouse gas? | Water vapor, because it's much more abundant than carbon dioxide. |
| What was the role of atmospheric CO2 concentration in the glacial cycles of the past ~800,000 years? | When temperature changes enough, positive and negative feedbacks are engaged, and carbon dioxide is engaged in positive feedbacks (making them faster and somewhat more extreme). |
| If the direct effect of rising atmospheric CO2 by itself increased temperature by 1oC, roughly how much would the temperature increase after accounting for the water vapor feedback? | It would increase by 2 degrees Celsius because the water vapor feedback is about 100 percent of the effect of rising atmospheric carbon dioxide. |
| How do anthropogenic aerosols affect climate, on average? | They cool the climate overall. |
| Does rising CO2 concentration increase or decrease stomatal conductance? | It decreases stomatal conductance, because the stomata close somewhat. |
| Why does nitrogen become more limiting to photosynthesis under elevated atmospheric CO2 concentration? | The elevated CO2 concentration dilutes Nitrogen and other nutrients. |
| What are some reasons that yield might not increase in response to climate warming, even if the rate of photosynthesis increases? | Earlier flowering can cause mismatches with the timing of pollinator lifecycles, more rapid growth can lead to the depletion of soil resources before grain-filling, and insect pests can better survive warmer winters. |
| What are some reasons that climate warming might not increase the rate of photosynthesis? | If the temperature is high enough, it may be above the optimal temperature for the (3-D) enzymes involved in photosynthesis, causing them to unfold. Also, rising temperatures increase the vapor pressure deficit, somewhat closing the stomata. |
| Would decreasing CO2 concentration increase or decrease stomatal conductance? | It increases stomatal conductance, because the stomata open somewhat. |
| Why is Rubisco notable, compared to other proteins? | It's the most abundant protein on Earth, the most abundant protein in leaves, and the biggest reason crops need Nitrogen. |
| What is the most quantitatively important reason that plants need water? | To replace water lost via transpiration. |
| What is the functional significance of the Casparian strip in roots? | It forces water (or solution) to cross membranes. |
| Under what environmental conditions is C4 photosynthesis better than C3 photosynthesis? | Under warm and sunny conditions. |
| What are the ultimate electron donor and acceptor in photosynthesis? | The ultimate donor is water and the ultimate acceptor is carbon dioxide. |
| What are the essential macronutrients for plants? | Sulfur (S), Nitrogen (N), Calcium (Ca), Phosphorous (P), Potassium (K), and Magnesium (Mg). |
| What is a meristem? | A region of unspecialized cells in a plant capable of cell division. |
| What are the two generations of land plants? | Nonvascular (gametophyte-dominant) and vascular (sporophyte-dominant). |
| Which generation of land plants makes spores? | Vascular. |
| Which generation of land plants makes gametes? | Non-vascular. |
| Why might a farmer prefer to use clonal propagation rather than seeds to produce lots of plants? | They want a large amount of plants with a specific trait. |
| From which area of a plant – more distal (farther from the base) or more basal (closer to the base) – would you take a cutting if your objective were to create a whole new plant? Why? | More basal, because the juvenile tissue closer to the base is the most likely to root. |
| A colorful, fleshy structure contains a seed. Is the structure necessarily a fruit, and why? | No, because the structure has to have been derived from the ovary of a flower, which was not assumed here. |
| True or False: Very little acreage in the US is actually planted with genetically engineered crops. | False, because more than ninety percent of corn, soybean, and cotton grown in the US is genetically-modified. |
Created by:
user-2017926