BZ 440 FINAL EXAM QUESTIONS ANSWERED CORRECTLY LATEST
UPDATE 2026
What parameters do plants sense in light? - Answers Quality, intensity, and duration
What are photoreceptors in plants responsible for? - Answers Absorbing specific
wavelengths and triggering signaling cascades that alter gene expression
How many types of photoreceptors are there in plants? - Answers Three types
What are the two forms of phytochromes? - Answers Pr (inactive) and Pfr (active)
What happens to phytochrome when exposed to red light? - Answers It converts from
Pr to Pfr
What is the role of Pfr in plants? - Answers It moves into the nucleus and regulates
developmental transitions
What triggers shade-avoidance responses in plants? - Answers Low red-to-far-red
light ratios beneath canopy shade
What is phototropism? - Answers Growth of a plant towards light, caused by altered
auxin transport
What regulates stomatal opening in response to blue light? - Answers
Phosphorylation of the H+-ATPase in guard cells
How do short-day plants determine the right time for flowering? - Answers Nights
must exceed a species-specific minimum duration
What is the coincidence model in flowering? - Answers It explains flowering when
the expression of the flowering master gene overlaps with daylight
What is the role of CONSTANS (CO) in flowering? - Answers It activates FT in
long-day plants and inhibits it in short-day plants
What is the function of the FT protein? - Answers It acts as a florigen and moves
from leaves to the shoot apical meristem
What does the ABC model explain? - Answers How A, B, and C gene combinations
specify floral organ identity
What is vernalization? - Answers The process that removes repression at the
meristem through epigenetic modifications
What is double fertilization in angiosperms? - Answers It produces a diploid embryo
and a triploid endosperm
What triggers fruit development after fertilization? - Answers Seeds release auxin
and gibberellins signaling the ovary
What characterizes climacteric fruits? - Answers They undergo a burst of respiration
and ethylene production during ripening
What is parthenocarpy? - Answers The production of seedless fruits when auxin or
GA mimics the fertilization signal
What is the aleurone layer's role in seeds? - Answers It regulates dormancy and
produces enzymes for reserve mobilization during germination
What is the difference between dormancy and quiescence in seeds? - Answers
Dormancy prevents germination under favorable conditions; quiescence occurs due to
unfavorable conditions
What is vivipary in seeds? - Answers When seeds germinate while still attached to
the mother plant
What environmental cues can break seed dormancy? - Answers Light, cold
stratification, and chemicals like nitrate and smoke-derived chemicals
What marks the completion of germination? - Answers Radicle emergence
, What are the three phases of water uptake during germination? - Answers Rapid
imbibition, metabolic lag phase, and increased uptake during seedling growth
What is the role of gibberellins in seed germination? - Answers They promote
germination by degrading DELLA proteins, which repress germination
What happens to light-grown seedlings compared to dark-grown seedlings? -
Answers Light-grown seedlings have short hypocotyls and expanded green leaves,
while dark-grown have long hypocotyls and closed cotyledons
What triggers photomorphogenesis in seedlings? - Answers A single flash of light
Which hormones promote etiolation in darkness? - Answers Gibberellins (GAs) and
brassinosteroids
What role does light play in apical hook formation? - Answers Light reduces ethylene
production on the inner side, reducing growth inhibition.
How does auxin affect cell walls? - Answers Auxin loosens cell walls by acidifying
the apoplast and activating expansins.
What are the distinct zones of root development? - Answers Root cap, meristematic
zone, elongation zone, and maturation zone.
What promotes root hair formation? - Answers Ethylene promotes root hair
formation.
Which hormones inhibit root hair development? - Answers Brassinosteroids inhibit
root hair development.
What causes tropisms in plants? - Answers Asymmetric auxin distribution and
differential cell elongation.
How does auxin transport occur in shoots and roots? - Answers Auxin transport is
polar and gravity-independent, moving basipetally in shoots and according to the
fountain model in roots.
What determines the direction of auxin flow? - Answers PIN proteins determine the
direction of auxin flow.
What triggers gravitropism in plants? - Answers Statolith sedimentation in the root
cap and shoots triggers auxin redistribution.
What is apical dominance? - Answers Apical dominance occurs when auxin from the
shoot tip suppresses axillary bud outgrowth.
How do strigolactones affect axillary buds? - Answers Strigolactones reinforce apical
dominance by activating BRC1 and suppressing cytokinin synthesis.
What role do cytokinins play in plant growth? - Answers Cytokinins promote axillary
bud growth and overcome apical dominance.
What is the effect of sucrose on bud release? - Answers Sucrose acts as an early
signal in bud release after decapitation.
How does root architecture adapt to nutrient deficiencies? - Answers By reducing
primary root growth and increasing lateral root and root hair development.
What is senescence in plants? - Answers Senescence mobilizes nutrients from aging
organs to younger tissues.
Which hormone delays senescence? - Answers Cytokinins delay senescence.
What are the three types of biotic interactions? - Answers Mutualism, commensalism,
and parasitism.
What is mutualism in plant interactions? - Answers Mutualism benefits both partners,
such as through pollination and mycorrhizal associations.
How do plants defend against herbivores? - Answers Plants rely on physical barriers,
secondary metabolites, and signaling molecules.
What are glucosinolates? - Answers Sulfur-rich defense compounds that convert to
toxic products when tissue is damaged.
UPDATE 2026
What parameters do plants sense in light? - Answers Quality, intensity, and duration
What are photoreceptors in plants responsible for? - Answers Absorbing specific
wavelengths and triggering signaling cascades that alter gene expression
How many types of photoreceptors are there in plants? - Answers Three types
What are the two forms of phytochromes? - Answers Pr (inactive) and Pfr (active)
What happens to phytochrome when exposed to red light? - Answers It converts from
Pr to Pfr
What is the role of Pfr in plants? - Answers It moves into the nucleus and regulates
developmental transitions
What triggers shade-avoidance responses in plants? - Answers Low red-to-far-red
light ratios beneath canopy shade
What is phototropism? - Answers Growth of a plant towards light, caused by altered
auxin transport
What regulates stomatal opening in response to blue light? - Answers
Phosphorylation of the H+-ATPase in guard cells
How do short-day plants determine the right time for flowering? - Answers Nights
must exceed a species-specific minimum duration
What is the coincidence model in flowering? - Answers It explains flowering when
the expression of the flowering master gene overlaps with daylight
What is the role of CONSTANS (CO) in flowering? - Answers It activates FT in
long-day plants and inhibits it in short-day plants
What is the function of the FT protein? - Answers It acts as a florigen and moves
from leaves to the shoot apical meristem
What does the ABC model explain? - Answers How A, B, and C gene combinations
specify floral organ identity
What is vernalization? - Answers The process that removes repression at the
meristem through epigenetic modifications
What is double fertilization in angiosperms? - Answers It produces a diploid embryo
and a triploid endosperm
What triggers fruit development after fertilization? - Answers Seeds release auxin
and gibberellins signaling the ovary
What characterizes climacteric fruits? - Answers They undergo a burst of respiration
and ethylene production during ripening
What is parthenocarpy? - Answers The production of seedless fruits when auxin or
GA mimics the fertilization signal
What is the aleurone layer's role in seeds? - Answers It regulates dormancy and
produces enzymes for reserve mobilization during germination
What is the difference between dormancy and quiescence in seeds? - Answers
Dormancy prevents germination under favorable conditions; quiescence occurs due to
unfavorable conditions
What is vivipary in seeds? - Answers When seeds germinate while still attached to
the mother plant
What environmental cues can break seed dormancy? - Answers Light, cold
stratification, and chemicals like nitrate and smoke-derived chemicals
What marks the completion of germination? - Answers Radicle emergence
, What are the three phases of water uptake during germination? - Answers Rapid
imbibition, metabolic lag phase, and increased uptake during seedling growth
What is the role of gibberellins in seed germination? - Answers They promote
germination by degrading DELLA proteins, which repress germination
What happens to light-grown seedlings compared to dark-grown seedlings? -
Answers Light-grown seedlings have short hypocotyls and expanded green leaves,
while dark-grown have long hypocotyls and closed cotyledons
What triggers photomorphogenesis in seedlings? - Answers A single flash of light
Which hormones promote etiolation in darkness? - Answers Gibberellins (GAs) and
brassinosteroids
What role does light play in apical hook formation? - Answers Light reduces ethylene
production on the inner side, reducing growth inhibition.
How does auxin affect cell walls? - Answers Auxin loosens cell walls by acidifying
the apoplast and activating expansins.
What are the distinct zones of root development? - Answers Root cap, meristematic
zone, elongation zone, and maturation zone.
What promotes root hair formation? - Answers Ethylene promotes root hair
formation.
Which hormones inhibit root hair development? - Answers Brassinosteroids inhibit
root hair development.
What causes tropisms in plants? - Answers Asymmetric auxin distribution and
differential cell elongation.
How does auxin transport occur in shoots and roots? - Answers Auxin transport is
polar and gravity-independent, moving basipetally in shoots and according to the
fountain model in roots.
What determines the direction of auxin flow? - Answers PIN proteins determine the
direction of auxin flow.
What triggers gravitropism in plants? - Answers Statolith sedimentation in the root
cap and shoots triggers auxin redistribution.
What is apical dominance? - Answers Apical dominance occurs when auxin from the
shoot tip suppresses axillary bud outgrowth.
How do strigolactones affect axillary buds? - Answers Strigolactones reinforce apical
dominance by activating BRC1 and suppressing cytokinin synthesis.
What role do cytokinins play in plant growth? - Answers Cytokinins promote axillary
bud growth and overcome apical dominance.
What is the effect of sucrose on bud release? - Answers Sucrose acts as an early
signal in bud release after decapitation.
How does root architecture adapt to nutrient deficiencies? - Answers By reducing
primary root growth and increasing lateral root and root hair development.
What is senescence in plants? - Answers Senescence mobilizes nutrients from aging
organs to younger tissues.
Which hormone delays senescence? - Answers Cytokinins delay senescence.
What are the three types of biotic interactions? - Answers Mutualism, commensalism,
and parasitism.
What is mutualism in plant interactions? - Answers Mutualism benefits both partners,
such as through pollination and mycorrhizal associations.
How do plants defend against herbivores? - Answers Plants rely on physical barriers,
secondary metabolites, and signaling molecules.
What are glucosinolates? - Answers Sulfur-rich defense compounds that convert to
toxic products when tissue is damaged.
