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64 Cards in this Set
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Explain two reasons why plants and animals require constant inputs of energy. |
to survive and to reproduce |
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Through evolutionary time, life on earth has become more complex and ordered. Why doesn’t this violate the 2nd law of thermodynamics? |
Organisms increase their order at the expense of disorder in their surroundings |
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Define metabolic equilibrium? Why must organisms maintain metabolic disequilibrium? How does waste excretion contribute to maintaining metabolic disequilibrium? |
Equilibrium: low energy state where change will not happen without input of energy. disequilibrium allows necessary rxns for life to occur. waste excretion releases chemicals that could catalyze unnecessary rxns. |
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What are the basic chemical equations summarizing photosynthesis and respiration? |
Photosynthesis: 6CO2 + 6H2O + light energy = C6H12O6 + 6O2 Cellular respiration C6H12O6 + O2 = 6CO2 + 6H2O + Energy |
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Why is ATP good for storing energy short-term but poor for storing it over longer periods of time? |
ATP is a good carrier of energy but is easily reacted and broken down, organic compounds provide higher yeild over longer periods of time |
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Define a redox reaction. In cellular respiration, what is oxidized and what is reduced? Why does this reaction release energy? In photosynthesis, what is oxidized and what is reduced? |
a redox rxn is the movement of electrons. Carbohydrates are oxidized and oxygen is reduced. proton gradients produce atp. in photosynthesis, CO2 is reduced and H2O is oxidized. |
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Explain the concept of an electron transport chain as it applies to photosynthesis and respiration. What work is performed as electrons are transported down this gradient? How is this work used to generate ATP? |
as the electron moves through the electron transport chain, H+ is released on one side of a membrane. when H+ moves to the other side of the membrane at the end of the chain, ATP is synthesized. |
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What is the role of oxygen in cellular respiration? |
O2 is the oxydizing agent in the redox reaction, it takes extra electrons |
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Define homeostasis: |
Maintenance within the organisms body that allow biological reactions to proceed normally. requires excretion of wastes. |
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With regards to water, energy, nutrients, and waste excretion, the desert tortoise maintains homeostasis on a yearly rather than daily basis. Explain this statement, describing how the animal accomplishes each of these tasks. |
stores water in its bladder. acquires energy and water from grass in spring, nutrients from dry plants near fall. |
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Describe three pieces of evidence that mitochondria and evolved from symbiotic mutualisms between a eukaryote (or eukaryote ancestor) and bacteria |
1. Organelles regenerate through binary fission, cannot regenerate from nuclear DNA. 2. DNA sequences similar to bacteria. 3. Bacteria and organelles are circular. |
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Identify at least one step where each of the following types of energy are produced during photosynthesis: covalent bond, excited electrons, electronegativity, chemical gradient |
covalent bonds are formed in calvin cycle when glucose is made. in light reaction, light excites electrons in chloroplasts. in calvin cycle when water is produced there is electronegativity. in calvin cycle when atp is produced, chemical gradients are present. |
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How are excited electrons generated during photosynthesis? Where does this reaction take place? |
Chlorophyll losses e- when light hits magnesium. gains e- from water splitting. light excites e- |
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How is O2 produced during photosynthesis? What is the source of the oxygen atoms? |
light energy from the sun is absorbed by photosystem II and it is used to split a molecule of water. |
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When carbohydrates are produced during photosynthesis, what is the chemical source for the C? the H? the O? |
The souce of C is CO2 as well as the source of O2. The source of H is the splitting of H2O. |
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Why do plants need to perform cellular respiration? What constraints does cellular respiration place on plants’ physiology? |
Plants perform cellular respiration in order to produce ATP. the more cellular respiration a plant undergoes the less glucose is available for plant growth |
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What traits are shared and different between plants and their green algae ancestors? How do unique traits of plants help them survive on land |
Algae is nonvascular, and many forms are single celled. some are multicellular however, and both plants and green algae are photosynthetic. nutrient uptake and reproductive differences in plants help them survive on land. |
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What constraints does photosynthesis place on plants’ physiology? How do the properties of RUBISCO make accommodating photosynthesis more challenging for land plants? |
when its dark, the light reaction cant occur, which makes ATP and adds H+ to the thykaloid space. If plant cannot open stoma, then CO2 cannot get in and the calvin cycle is halted which effects growth. RUBISCO can take up O2 instead of CO2 when CO2 is scarce, which wastes energy. |
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Define photorespiration. Why is it a problem for plants? What conditions cause high rates of photorespiration? |
when RUBISCO binds to oxygen instead of CO2. this reduces efficiency of photosynthesis and occurs when the plant has low CO2 levels, for example during droughts. |
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Explain why water loss and photosynthesis are linked in plants. What role does photorespiration play in this trade-off? |
water is essential in both the light and calvin cycle. H2O splitting is needed to provide e- for light to excite and to add H+ to thykaloid space. when plants close their stoma to conserve water, no CO2 can get in and this is where photorespiration can occur. |
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How would you expect plant growth to respond to increased CO2 concentration in the atmosphere? Explain your answer with regard to gas exchange, photorespiration, water loss, and stomata. |
pressuming water levels are at an adequate level, higher concentration of CO2 would mean more glucose synthesis. if the plants experiencing water loss it wont matter because the stomata is closed so gas exchange is halted which means O2 is built up in the plant and photorespiration can occur. |
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The graph below shows our best understanding of how CO2 concentration in the atmosphere varied through the past 500 million years of earth’s history. How might these changes have affected the evolution of land plants? Consider morphological and metabolic adaptations. |
when CO2 was more abundant i suspect plants didnt have to be concerned about CO2 starvation even during droughts. as concentrations decreased i expect plants found a more efficient way of converting CO2 to glucose, stomata size may have increased. |
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What are the 3 major steps in photosynthesis? Where and when do they take place in C3, C4 and CAM plants? |
The light reaction which happens during the day for all plants. uptake of CO2 which C4 plants do in mesophyll cells, and CAM plants do at night. Carbon fixation which C4 plants do in bundle sheath cells, and CAM plants do in mesophyll cell. |
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In addition to C4 and CAM photosynthesis, describe 2 other adaptations of plants to reduce water loss and photorespiration. |
Plants can keep their stomata closed to reduce water loss. plants regulate stomata openings to try and balance C and water levels. |
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Some leaf molds that parasitize plants secrete a chemical that causes guard cells to accumulate potassium ions. How does this help the fungus infect the leaf? |
well K+ are used to regulate guard cells. K+ in means guard cells lengthen and open. K+ out means guard cells shrink and close. if the stomata is open because of the leaf molds infecting them with K+, this makes it easy for the fungi to enter the leaf. |
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One July day in Venus, TX temperatures reach a record 110 F in my grandfather’s sweet potato patch, and the soil continues drying around the sweet potato roots. Overnight, the weather cools. The following morning is muggy (hot but humid) and thunderclouds begin forming around noon. In the afternoon, it is windy and rainy. Assume that sweet potatoes are a C3 plant. How will their stomata react to the weather? What specific cues will cause them to open or close? |
C3 plants close their stomata in dry hot environments. so they would be closed primarily when water stressed. the stomata wouldnt open again until the afternoon when water can be absorbed through the rain in the soil. |
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What is the role of cohesion in water movement within plants? |
cohesion is the attractive force between molecules, in this case water. cohesion is responsible for water movement through the xylem |
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Define cavitation and explain why it is a problem for plants. What conditions promote cavitation? |
cavitation is the formation of air pockets in the xylem, which disrupts cohesion and therefore disrupts its ability to move water. this occurs in water stressed plants. |
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Some (but not most) plants are capable of absorbing water through their stomata when conditions are right. Redwoods are one species that is capable of this form of water uptake. If redwoods absorb water from fog through their stomata, which of the following must be true: |
water potential in stomata is 0. water potential in stomata is less than 0. water potential in stomata is less than foggy air. water potential in stomata is more than foggy air. water potential in stomtata is greater than 0. |
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describe water potential in pressure and solute terms. |
pressure can be + or -, plant cells have +. solute potential is always negative, except for water which is always 0. |
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Define guttation and hydraulic lift. Explain each of these processes in terms of relative water potential in soil and roots, and how movements of water in plants differ between day and night. |
Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. Root pressure provides the impetus for this flow, rather than transpirational pull, and it occurs at night. Hydraulic lift, at night water goes from deep roots to shallow soil. this increases water availability during the day since shallow soil has less water, adding water means the plant can get water from multiple places. |
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Rank the following in terms of their frequency of occurrence in different plant species and their ecological importance: transpiration, guttation, hydraulic lift |
transpiration occurs in most plants, guttation happens in grasses, and hydraulic lift happens in large trees. |
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A leaf falls from a tree onto the surface of a pond. The ψS of the pond is -0.5 MPa. The ψP and ψs of the leaf cells are 0.2 and -0.9 respectively. What is the ψp and ψ of the pond water? What is the ψ of the leaf cells? Will water move into or out of the leaf? |
the water pressure potential of the pond is -0.2, total water pressure of the pond is -0.7. the leaf cells have a water potential of -0.7. water will move into the leaf. |
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Define a circadian rhythm. Provide an example of a circadian rhythm in plants and one in animals. |
in plants, light sensitivity can cause different parts of photosynthesis to occur at different times. in animals, sundown signals a release of melatonin for sleeping. |
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Describe (or draw) and name the specialized cells in xylem for water transport. How do their properties make water transport efficient? What is the role of lignin in the xylem of woody plants? |
vascular cells that died at maturity, lignified, has pits in cell walls that allows water to pass. lignin is the polymer that makes wood hard and is hydrophobic. |
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Describe (or draw) and name the specialized cells in phloem for sugar/sap transport. How do their properties contribute to sap flow? How are they similar and different from xylem cells? |
sieve tube members alive but lack organelles. sap moved in sieve tubes by turgur pressure gradient. companion cells supply proteins, load sieve tubes with sugars. |
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What nutrients are plentiful and what nutrients are scarce for phloem-feeding insects such as aphids? How would the nutritional difficulties of phloem and xylem-feeding insects differ? |
sugars are plentiful, water is not. phloem feeding insects need a source of water, xylem feeding insects need a source or sugar. |
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How does an annual plant redirect sugars from growing leaves to fruits/seeds as it matures |
sugars are transport form young leaves to shoots. From older leaves to roots. |
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If roots were deprived of oxygen, how would their uptake of mineral nutrients change? How would their uptake of water change? |
if roots are deprived of oxygen, the plant will take in less nitrite and other mineral nutrients because there is no air space...............? water intake would increase |
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Systemic pesticides are taken up by plants and become part of their tissue. Diagram the route of a systemic pesticide applied to the soil as it moves through the plant. Explain what happens when the pesticide reaches the endodermis. |
gets in through the epidermis, then the cortex. Then it reaches the endodermis. The endodermis prevents water, and any solutes dissolved in the water, from passing through this layer via the apoplast pathway. This allows the plant to control to some degree the movement of water and to selectively uptake or prevent the passage of ions or other molecules. Apoplast is water moving through plasma membrane. SSymplast is water moving through cytoplasm. |
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How does each of the following contribute to efficient photosynthesis by plants? Stomata Xylem Circadian rhythms Hairs or other light-blocking structures on leaves of desert plant |
stomata on underside of leave. xylem bring water to leaves to be split. circadian rhythms tell the plant when to open or close stomata. not sure what hairs do |
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Compare photosynthesis and cellular respiration. What are the inputs and products of each? What organelles are involved? What constraints does cellular respiration place on plants? Describe a plant adaptation that allows plants to use cellular respiration for metabolic energy in a non-green (i.e. non-photosynthesizing) part of the plant. |
photosynthesis: CO2 + Light + H2O --> Glucose + O2 +energy. chloroplast. cellular respiration: glucose + oxygen --> CO2 + H2O + energy. mitochondria. |
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Which of the following require plants to expend energy: Transport of water through plant xylem Loading of sugar into plant phloem Transport of sugar through plant phloem Uptake of mineral nutrients through plant roots Transpiration Movement of potassium ions to open and close guard cells Building complex organic molecules from simple sugars formed during photosynthesis Maintenance of complex, highly structured plant bodies through time, and evolution of new, more complex body forms during the history of life Photorespiration Incorporation of CO2 into organic sugars in CAM or C4 photosynthesis |
Loading of sugar into plant phloem. Transport of sugar through plant phloem. transpiration. movement of potassium ions.building complex molecules, photorespiration, cam and c4. |
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If the ψ of air around a tree is -14, the ψ inside the stomata is -7, and the ψ of the xylem in the leaf is -5, will transpiration occur? Why or why not? |
yes because water moves from higher potential to lower potential. it will move from xylem to stomata to the air. |
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A filament of algal cells has a P of 0.25 MPa and a s of -0.45 MPa. The filament is arranged so that one end is dipped into a beaker with a solution with s = -0.3 MPa and the other end of the filament is dipped into a beaker of pure water. Will osmosis occur? If so, in which direction will water flow? |
water will move into the beaker with -.3 because it has lower water potential than the algae cells -.2. |
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In my Aunt Jo’s pickle recipe theS of the pickling solution is -5 MPa. The S of your average cucumber is -4 MPa, and the P is 1 MPa. Will the cucumber lose or absorb water during pickling? What effect will this have on the pickles? |
the cucumber should lose water during this process which should create a higher concentration of sugars and nutrients in the pickles. |
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The S of leaf epidermal cells surrounding a stoma is -1.8 and the P is 1.6. The current S of the guard cells for the stoma is -2.3 and the P is 1.2. Will water move into or out of the guard cells? What effect is this likely to have on the stoma? |
water will move into the guard cells which should cause the stoma to open. |
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From the film “What Plants Talk About”, describe 2 examples of chemically-mediated interactions between different plant species. |
nap weed plants usually kill grasses, but theres a plant that is immune and releases a chemical that protects nearby plants. when plants are being predated, they release chemical signals to nearby plants to warn them. |
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From the film, “What Plants Talk About”, describe an example of a chemical communication between a specific plant and an animal species. |
in the tobacco plant, when they are being eaten by caterpillars, they send a signal to the caterpillars predators to come eat them. |
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From the film, “What Plants Talk About” describe a plant growth or behavioral response to changing environmental conditions. |
i dont know well shizznits. |
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Suppose I discover a new species of blood-red orchid growing in the Selkirk mountains. I would like to try to propagate it and perhaps develop a horticultural variety. When I dig it up, I notice that its roots are growing in soil full of fungal hyphae, and I suspect that it has an association with mycorrhizal fungi. How could I determine whether it has endomycorrhizae or ectomycorrhizae? |
the hyphae of the endomycorrhizae not only grow inside the root of the plant but penetrate the root cell walls and become enclosed in the cell membrane as well. ectomycorrhizal fungi do not penetrate their host’s cell walls. Instead, they form an entirely intercellular interface, consisting of highly branched hyphae forming a latticework between epidermal and cortical root cells, known as the Hartig net. |
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Define meristem tissue of a plant. In a plant that has only primary growth (for example a short-lived herbaceous plant such as Arabidopsis), where are the meristems located? Draw a plant with only primary growth, including both root and shoot systems, and indicate the location of the meristems. |
Meristematic cells give rise to various organs of the plant and keep the plant growing.. |
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Describe 2 mutualistic relationships between plants and other organisms that help them acquire nutrients. What are the costs and benefits for each partner? |
butterflies that lay larvae on the plants they pollinate. caterpillars eat leaves but biggest pollinator. to many larvae kill food source for mature butterfly. |
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Diagram the global P cycle. What processes are particularly important to determining P availability to plants? What geological conditions cause P to be particularly scarce? |
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Define mycorhizae. What is the difference between ectomycorhizae and endomycorhizae? Which is more common? |
Mycorrhizae are symbiotic relationships that form between fungi and plants. The fungi colonize the root system of a host plant, providing increased water and nutrient absorption capabilities while the plant provides the fungus with carbohydrates formed from photosynthesis. ENDO is more common |
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Will the vertical distance between two specific branches on a tree change over the years? Why or why not? |
no. trees lengthen at their tips and this has no effect on the length of previously formed branches. |
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What are two functions of the root cap: |
root cap is a shaped like a thimble and acts like a hard hat for the root tip. Directly behind it is where root growth actually occurs. If the cap is carefully removed the root will grow randomly, so it also controls amount of growth. |
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Some plants that often experience heavy grazing be deer or other mammals have higher fitness when grazed than when grazers have been excluded. How could mammalian grazing change the growth pattern of plants to improve their reproductive success? What hormones might be involved |
increased photosynthetic activity, compensatory growth, phenological changes, utilizing stored reserves, reallocating resources, increase in nutrients uptake, and plant architecture |
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How do each of the following contribute to efficient photosynthesis by plants? Root nodules harboring nitrogen fixing bacteria Mycorrhizae Phototropism Apical dominance Abscissic acid |
dunno |
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Would you expect symptoms of iron deficiency to show up first in old or young leaves |
young leaves, involved in the chlorophyll |
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Name and describe the 5 microbial transformations of nitrogen. For each, what chemical form of nitrogen is the input and what chemical form is the output? Which one makes N biologically available? Which one returns N to the atmosphere? For each of these transformations, how does it benefit the microbes involved? |
1. nitrogen fixaton, N2 --> NH3 or NH4+, nitrogen fixing bacteria. 2. Assimilation, takes ammonium (or NO3-) and converts into organic molecule. 3. nitrofying bacteria NH4+ + O2 --> NO3, this makes energy for the bacteria. 4.denitrification NO3 --> N2 releases N2 into atmosphere Mineralization is taking organic forms of nitrogen and converting it into ammonium. |
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Why does absorption of nutrients through plant roots require energy? |
Nutrient uptake from the soil is achieved by cation exchange, where root hairs pump hydrogen ions (H+) into the soil through proton pumps. These hydrogen ions displace cations attached to negatively charged soil particles so that the cations are available for uptake by the root. |
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Define each of the following: essential nutrient, macronutrient, micronutrient, limiting nutrient |
must have to complete life cycle, more than 1%, less than 1%, in the shortest supply |
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Define each of the following and explain its role in regulating plant uptake of materials from soils: Cell wall, cell membrane, apoplastic route, symplastic route, plasmodesmata, endodermis, casparian strip, suberin, xylem |
yeah tommorow maybe |
