Photosynthetic Mechanisms Quiz
63 Questions
1 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the key enzyme involved in the photosynthetic process?

  • Rubicon, which is crucial for water uptake
  • Rubisco, which is very N-expensive (correct)
  • ATP synthase, which generates energy from light
  • Enolase, which is essential for CO2 fixation

    • What is the primary function of the Calvin Cycle in photosynthesis?

  • To regulate water loss through transpiration
  • To reduce and fix CO2 into organic molecules (correct)
  • To capture light energy and release oxygen
  • To generate energy from ATP synthesis

    • What factor influences conductance in the photosynthetic process?

  • Soil pH levels
  • Temperature fluctuations
  • Leaf coloration
  • Stomata opening and closing (correct)

    • What represents a positive carbon balance in plant physiology?

    <p>Addition of carbon as carbohydrates</p> Signup and view all the answers

    In the context of photosynthesis, what does LCP stand for?

    <p>Light Compensation Point</p> Signup and view all the answers

    How is the carbon exchange rate calculated in photosynthesis?

    <p>(Net Photosynthesis / Conductance) x (Cair - Cinternal)</p> Signup and view all the answers

    Why is it mentioned that small Sugar Maple saplings in forest shade can be decades old?

    <p>To illustrate their slow growth and suppression of reproduction in shade</p> Signup and view all the answers

    What is the significance of low light compensation points (LCP) for plant survival?

    <p>Plants with low LCP require less light to meet their respiratory needs</p> Signup and view all the answers

    What does the text suggest about the relationship between light availability and growth in forest plants?

    <p>Sunflecks and canopy gaps provide opportunities for rapid growth in forest plants</p> Signup and view all the answers

    Why do late successional dominant plants have lower LCP according to the text?

    <p>For better shade tolerance at the cost of slower growth</p> Signup and view all the answers

    How do holes in the forest canopy created by dead trees impact understorey plant growth?

    <p>The holes create a high-light environment, favoring rapid growth in understorey plants</p> Signup and view all the answers

    Why do deciduous forest species often have the ability to adapt to seasonally changing light availability according to the text?

    <p>As a result of their low LCP allowing them to meet their respiratory needs in low light conditions</p> Signup and view all the answers

    What is the primary problem associated with the RUBISCO enzyme in C3 photosynthesis?

    <p>Consumes O2 to release CO2</p> Signup and view all the answers

    Which photosynthetic mechanism is characterized by a spatial separation of CO2 uptake and carbohydrate production?

    <p>C4 photosynthesis</p> Signup and view all the answers

    Why are C4 plants more water-efficient compared to C3 plants?

    <p>Less need for stomata to be open</p> Signup and view all the answers

    In which type of environment do C3 grasses predominate?

    <p>Cooler months with rainfall</p> Signup and view all the answers

    What is a key disadvantage of CAM photosynthesis compared to C3 photosynthesis?

    <p>Temporal separation of CO2 uptake and Calvin cycle</p> Signup and view all the answers

    What is the main advantage of PEP carboxylase in the context of photosynthesis?

    <p>Inhibits photorespiration</p> Signup and view all the answers

    Why does CAM photosynthesis save water compared to other mechanisms?

    <p>Stomata open at cooler, humid night times</p> Signup and view all the answers

    Which type of grasses show higher productivity in hotter, drier environments?

    <p>C4 grasses</p> Signup and view all the answers

    What is the primary limitation on the growth and photosynthetic rates of CAM plants?

    <p>Temporal separation between CO2 uptake and Calvin cycle</p> Signup and view all the answers

    Why do C3 grasses predominate in habitats with rainfall in cooler months?

    <p>Rainfall availability matching growth requirements</p> Signup and view all the answers

    How do plants generally absorb nutrients from the soil?

    <p>As dissolved inorganic ions</p> Signup and view all the answers

    What is the primary source of nitrogen (N) for plants in the soil?

    <p>NH4+ and NO3- ions from dead organic material</p> Signup and view all the answers

    Why is the C:N ratio important for determining soil fertility?

    <p>It affects the competition between plants and microbes for nutrients</p> Signup and view all the answers

    How do plants ensure the uptake of minerals against concentration gradients in the roots?

    <p>Active transport using specialized uptake mechanisms</p> Signup and view all the answers

    Why is it important for plants to have specialized ion channels for nutrient uptake?

    <p>To facilitate movement of nutrients against concentration gradients</p> Signup and view all the answers

    In what forms do plants primarily absorb most mineral nutrients from the soil water?

    <p>Inorganic ions like NO3-, NH4+, and H2PO4-</p> Signup and view all the answers

    What is the primary function of arbuscular mycorrhizal (AM) fungi in relation to plants?

    <p>Enhancing water uptake and conservation in plants</p> Signup and view all the answers

    How do orchids like Coralroots and Indian Pipes depend on mycorrhizae for survival?

    <p>By using mycorrhizae as seedlings due to a lack of storage tissues</p> Signup and view all the answers

    What is a drawback mentioned in the text regarding the use of mycorrhizae in nutrient-rich soils?

    <p>Potential negative effects due to wrong fungal-plant combinations</p> Signup and view all the answers

    Why are mycorrhizae considered most useful in nutrient-poor soils?

    <p>To aid in nutrient uptake when soils lack nutrients</p> Signup and view all the answers

    What ecological role do insects play in relation to carnivorous plants mentioned in the text?

    <p>Providing essential nutrients to the plants</p> Signup and view all the answers

    How does cryptic parasitism by AM fungi impact plant-fungi relationships?

    <p>Raises concerns about having the wrong combination of fungi and plant</p> Signup and view all the answers

    What happens when the C:N ratio of dead leaf litter drops below 25 in the soil?

    <p>Decomposers start to free more N than they can use.</p> Signup and view all the answers

    Which type of decomposers degrade cellulose in wood?

    <p>Brown Rots</p> Signup and view all the answers

    What is the main reason for the failure of peatlands, leading to peat accumulation and reduced nutrient release?

    <p>Low water movement</p> Signup and view all the answers

    What is the primary result of anaerobic respiration due to low O2 levels in peatlands?

    <p>Reduced decomposition</p> Signup and view all the answers

    Which type of mycorrhizae is largely host-specific and surrounds the root?

    <p>(ECM) Ectomycorrhizae</p> Signup and view all the answers

    Why do litter from conifers decay slower than litter from deciduous plants?

    <p>Higher lignin content</p> Signup and view all the answers

    What is a key characteristic of Arbuscular mycorrhizae in terms of host specificity?

    <p>They are non-host-specific</p> Signup and view all the answers

    What is the primary source of N for plants in the soil?

    <p>Decomposition of dead organic material</p> Signup and view all the answers

    Why are organic molecules in soil useless for most plants?

    <p>They are too large to be absorbed by roots</p> Signup and view all the answers

    How do plants generally absorb most mineral nutrients from soil water?

    <p>As dissolved inorganic ions through the roots</p> Signup and view all the answers

    Why is the C:N Ratio important for determining soil fertility?

    <p>It indicates the balance between carbon and nitrogen in organic matter</p> Signup and view all the answers

    What is a key reason why herbivory is damaging to plants?

    <p>Reduction in nutrient recycling within plant systems</p> Signup and view all the answers

    How does mineralization of organic matter contribute to nutrient availability for plants?

    <p>Converts large organic molecules into forms that plants can absorb</p> Signup and view all the answers

    In what way do orchid seeds, like Coralroots and Indian Pipes, depend on mycorrhizae for survival?

    <p>By obtaining carbohydrates for energy</p> Signup and view all the answers

    Why are mycorrhizae considered more beneficial in nutrient-poor soils compared to rich soils?

    <p>As they are more profitable in such conditions</p> Signup and view all the answers

    What is the primary role of ectomycorrhizae in relation to plant protection?

    <p>Protecting from pathogens</p> Signup and view all the answers

    What characteristic distinguishes coralroots and Indian Pipes as 'cheaters' in the context of plant-fungi relationships?

    <p>Their parasitic behavior even in maturity</p> Signup and view all the answers

    What potential impact can incorrect combinations of fungi and plants have on plant growth?

    <p>Negatively affect nutrient uptake</p> Signup and view all the answers

    What is the significance of insects in the context of carnivorous plants mentioned in the text?

    <p>Insects serve as a rich source of nitrogen</p> Signup and view all the answers

    What is the primary reason for reduced microbial activity in peatlands?

    <p>Low pH caused by acidic fermentation</p> Signup and view all the answers

    Why does the decomposition rate of wood depend on its quality?

    <p>High cellulose content</p> Signup and view all the answers

    What is the significance of the C:N ratio in soil for decomposers?

    <p>C:N ratio above 25 limits decomposer growth</p> Signup and view all the answers

    What does excess inorganic nitrogen being lost to the soil signify?

    <p>Nitrogen becoming overabundant</p> Signup and view all the answers

    Why do decomposers start freeing more nitrogen than they can use when the C:N ratio drops below 25?

    <p>Nitrogen abundance in the soil</p> Signup and view all the answers

    What is the impact of lignin content on the decomposition of leaf litter?

    <p>Slows down decomposition</p> Signup and view all the answers

    Why are peatlands characterized by very low available nutrients?

    <p>Excessive water and poor drainage</p> Signup and view all the answers

    How does the C:N ratio of dead leaf litter change over time during decomposition?

    <p>Drops below 25 as microbes respire away CO2</p> Signup and view all the answers

    What is one main reason for the accumulation of peat in failed systems like peatlands?

    <p>Reduced microbial activity from low oxygen, leading to incomplete decomposition</p> Signup and view all the answers

    How does the form of carbon affect decomposers' growth in soils?

    <p>Easy-to-break-down forms inhibit nutrient cycling</p> Signup and view all the answers

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser