#plant physiology practice questions

cryptochrome

In darkness, COP1/SPA1 complex mainly causes:

Degradation of HY5 (B) is correct here. This is core cryptochrome: once you know the definition or pathway step, Degradation of HY5 is the clear fit. The wrong ones are A) Activation of HY5; C) Activation of cryptochrome; D) Inhibition of ubiquitination. If the topic is about gradients or potentials, water/solutes move from higher to lower of the relevant quantity.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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cryptochrome

Cryptochrome signaling requires which structural feature absent in photolyase?

Pick B: C-terminal extension. Thinking through cryptochrome step by step rules out the lookalikes and leaves C-terminal extension. Skip these: A) PHR domain; C) FAD-binding site; D) Dimerization site. For hormones and genes, match the molecule or gene to its real role, not a neighboring pathway.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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cryptochrome

Light perception by cryptochrome alters conformation of which region?

Go with B — C-terminal extension. Under cryptochrome, this is the standard explanation you’d use in class: it names the real driver or definition, while the rest are nearby but wrong. Not these: A) N-terminal PHR; C) PAS domain; D) DNA-binding domain. When two options sound similar, choose the one that matches the textbook definition most tightly.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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cryptochrome

Cryptochrome is structurally characterized by presence of:

B fits best: Photolyase homology region and C-terminal extension. Keep the cryptochrome basics straight and Photolyase homology region and C-terminal extension stands out as the precise answer. Avoid: A) Single domain only; C) Homeodomain; D) Leucine zipper. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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cryptochrome

The HY4 gene was later renamed as:

C fits best: CRY1. Keep the cryptochrome basics straight and CRY1 stands out as the precise answer. Avoid: A) CRY2; B) CRY3; D) PHYA. Light and flowering items often hinge on which photoreceptor or day-length rule is in play.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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PHYTOCHROME+PYQS

Photoreversibility of phytochrome refers to:

Answer: B) Interconversion between Pr and Pfr. For PHYTOCHROME, remember the key idea and you’ll land on this option; the distractors usually swap cause and effect or confuse similar terms. Avoid: A) Degradation of phytochrome in light; C) Binding of chromophore; D) Movement into nucleus. Name the process first, then pick the option that describes it — don’t reverse cause and effect.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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VERNALIZATION & FLOWERING+PYQS

In Arabidopsis, the major flowering repressor responsible for vernalization requirement is:

Answer: C) FLC. For VERNALIZATION & FLOWERING, remember the key idea and you’ll land on this option; the distractors usually swap cause and effect or confuse similar terms. Avoid: A) FT; B) SOC1; D) FD. Name the process first, then pick the option that describes it — don’t reverse cause and effect.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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PSS-Sec-E-Sensory biology

Long-day plants flower when:

Night length < critical (B) is correct here. This is core PSS-Sec-E-Sensory biology: once you know the definition or pathway step, Night length < critical is the clear fit. The wrong ones are A) Day length < critical; C) Night length > critical; D) Under darkness. If the topic is about gradients or potentials, water/solutes move from higher to lower of the relevant quantity.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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PSS-Sec-E-Sensory biology

Red light converts phytochrome Pr to:

Answer: C) Pfr. For PSS-Sec-E-Sensory biology, remember the key idea and you’ll land on this option; the distractors usually swap cause and effect or confuse similar terms. Avoid: A) Pr; B) Inactive form; D) UVR8. Name the process first, then pick the option that describes it — don’t reverse cause and effect.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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PSS-Sec-E-Sensory biology

Photoreceptors cryptochrome, phototropin and ZTL respond to:

Pick C: Blue/UV-A. Thinking through PSS-Sec-E-Sensory biology step by step rules out the lookalikes and leaves Blue/UV-A. Skip these: A) Red/Far-red; B) UV-B; D) Green light. For hormones and genes, match the molecule or gene to its real role, not a neighboring pathway.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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PSS-Sec-E-Sensory biology

Addition of blue light to saturating red light causes stomata to:

Correct option is C, Open further. In PSS-Sec-E-Sensory biology problems like this, the accurate statement is Open further; the others are common mix-ups. Not these: A) Remain unchanged; B) Close; D) Undergo damage. Tissue transport questions usually turn on xylem vs phloem, living vs dead cells, or source vs sink.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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PSS-Sec-E-Sensory biology

Phytochrome-mediated nuclear import occurs upon conversion to:

The right choice is B: Pfr. In PSS-Sec-E-Sensory biology, that matches how the process or concept actually works — the other choices mix up related ideas or use the wrong mechanism. Skip these: A) Pr; C) Inactive form; D) Phototropin. A quick check: if an option needs energy, pumps, or the opposite direction of movement, ask whether that really applies.

Ref: Best CSIR NET Plant Physiology books: Master Unit 6 with Taiz & Zeiger and Salisbury & Ross. Crack Part C experimental questions with top textbooks.

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