General
✓✗Which of the following is not an example of growth?
- Increase in surface area of a leaf
- Elongation of a pollen tube
- Swelling of a piece of dry wood placed in water
- Increase in the cell number of a root tip
General
✓✗Cells positioned away from the root apical meristem differentiate into
- epidermis cells
- xylem vessels
- root cap cells
- phloem sieve tubes
General
✓✗Which of the following is produced during water stress and brings about stomatal closure?
- Ferulic acid
- Abscisic acid
- Coumarin
- Ethylene
General
✓✗Cytokinins help to produce
- dormancy in seeds and in the buds of trees
- new leaves, chloroplasts and lateral shoots
- root hairs and lateral roots, but not shoots
- abscission layers at the base of the leaves
General
✓✗Charles Darwin and Francis Darwin concluded that
- gravity, not light, caused the coleoptile to bend over
- light directly stimulated cells on the lit side to grow faster
- the coleoptile tip sent an influence that caused bending
- the base of the coleoptile produced the growth substance
General
✓✗The most common naturally occurring auxin in plants is
- 2,4-dichlorophenoxyacetic acid
- indole-3-acetic acid
- naphthalene acetic acid
- gibberellic acid
General
✓✗Senescence of leaves is delayed by one PGR and promoted by another. These are, respectively,
- ethylene and gibberellin
- abscisic acid and cytokinin
- ethylene and cytokinin
- cytokinin and ethylene
General
✓✗F. Skoog observed that callus proliferated from the internodal segments of tobacco stem when auxin was supplied together with any one of the following, except
- abscisic acid
- coconut milk
- extract of vascular tissues
- yeast extract
General
✓✗At the cellular level, growth is principally a consequence of an increase in the amount of
- cell sap
- intercellular air
- protoplasm
- cell wall pectin
General
✓✗Thinning of cotton, cherry and walnut is done by applying ethylene because it
- increases the number of flowers on each branch
- induces dormancy in the seeds of the fruits
- delays the ripening of all the fruits on the tree
- accelerates abscission in flowers and fruits
General
✓✗An increase in the length of a root is best measured using
- the number of lateral roots only
- cell sap concentration
- the colour of root hairs
- a scale or ruler marking over time
General
✓✗A culture starts with 100 cells that double every 30 minutes (geometric growth). The number of cells after 2 hours is
- 1,600
- 3,200
- 400
- 800
General
✓✗Auxins help to prevent fruit and leaf drop at early stages but promote
- closure of stomata in young leaves
- dormancy of buds during the winter
- abscission of older, mature leaves and fruits
- germination of seeds in the dark
General
✓✗Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): Gibberellic acid is used to speed up the malting process in the brewing industry.
Reason (R): All gibberellins are acidic in nature.
In the light of the above statements, choose the correct answer from the options given below.
Assertion (A): Gibberellic acid is used to speed up the malting process in the brewing industry.
Reason (R): All gibberellins are acidic in nature.
In the light of the above statements, choose the correct answer from the options given below.
- Both Assertion and Reason are true and Reason is the correct explanation of Assertion
- Both Assertion and Reason are true but Reason is not the correct explanation of Assertion
- Assertion is true but Reason is false
- Both Assertion and Reason are false
General
✓✗Seeds rich in abscisic acid are likely to
- germinate immediately
- show parthenocarpy
- grow into tall seedlings
- remain dormant