Examkin

Soru

Zorluk: Çok zorPlant Science and Agricultural Technology

With reference to plant physiology, cellular transport mechanisms, and modern agricultural biotechnology, which of the following statements are correct?

  1. Agrobacterium tumefaciens utilizes T-DNA transfer via a type IV secretion system to integrate specific genetic material into host plant nuclear genomes, serving as a primary vector in crop genetic engineering.Cevap
  2. B
    Azotobacter and Clostridium species form obligate endosymbiotic bacteroid complexes within root nodules of leguminous crops to fix atmospheric nitrogen.
  3. Abscisic acid (ABA) induces stomatal closure under drought stress by activating efflux anion channels in guard cell membranes, leading to potassium ion loss and reduced turgor pressure.Cevap
  4. D
    Cytokinin phytohormones synthesized in shoot apical meristems undergo polar basipetal transport to maintain apical dominance and inhibit lateral branch outgrowth.

Cevap

The correct statements are the one describing Agrobacterium tumefaciens genetic transformation and the one explaining Abscisic acid-mediated stomatal closure during water stress.
The statements regarding Agrobacterium tumefaciens T-DNA insertion and Abscisic acid (ABA)-induced stomatal closure are correct. Agrobacterium utilizes a bacterial type IV secretion apparatus encoded by Vir proteins to insert recombinant T-DNA into plant nuclei. ABA serves as the key plant stress hormone, opening guard cell anion channels to lose potassium ions and turgor pressure, thereby conserving water.

Adım Adım Çözüm

1
Evaluate the statement on Agrobacterium tumefaciens genetic transfer mechanisms.
Agrobacterium tumefaciens transfers T-DNA from its Ti plasmid into host plant chromosomes using a vir-gene encoded type IV secretion system. This statement is scientifically accurate.
Agrobacterium is widely recognized as Nature's genetic engineer for recombinant plant technology.
2
Analyze the nitrogen-fixing bacteria classification statement.
Azotobacter (aerobic) and Clostridium (anaerobic) are free-living bio-fertilizer microbes, not nodule-forming endosymbionts like Rhizobium. This statement is incorrect.
Distinguishing free-living nitrogen fixers from symbiotic bacteroid associations is essential in soil microbiology.
3
Examine the physiological pathway of ABA-induced stomatal regulation.
Abscisic acid binds guard cell receptors, triggering intracellular calcium spikes, activating SLAC1 anion channels, causing mass efflux of K⁺ and osmotic water exit. This statement is scientifically accurate.
ABA is the primary stress phytohormone preventing transpirational water loss.
4
Assess the source, transport direction, and physiological role of cytokinins versus auxins.
Polar basipetal transport and apical dominance suppression of lateral buds are signature characteristics of auxins, not cytokinins. This statement is incorrect.
Cytokinins counteract apical dominance and promote lateral shoot growth.

Anahtar Kavram

Plant Hormone Signaling, Bio-fertilizer Microorganisms, and Recombinant Agrobacterium Vector Technology
Tahmini Süre:1m 30s
Bu soruyu puanla

Konular

Plant Science and Agricultural Technology

Bu konudan daha fazla soru