FREE NEET Biology Practice MCQ Test: Plant Growth And Development Exercise 4 Questions Answers With Detailed Explanations [PDF]

Answer: (a)

Answer: (a)

Answer: (c)

Biosynthesis of abscisic acid (ABA) in most plants occur indirectly by degradation of certain carotenoids present in chloroplasts or other plastids. The biosynthetic pathway follow mevalonic acid pathway for their synthesis. The sites of synthesis are fruits, tissues, leaves, roots and seeds.

Answer: (c)

Answer: (a)

Answer: (b)

Answer: (d)

Long day plants undergo flowering after receiving light above a critical day length. e.g. spinach, sugarbeet. Short day plants flower only when they receive light below a critical day length, e.g. Glycine max, tobacco.

Answer: (a)

Answer: (b)

In geometric growth, if total growth is plotted against time, an S-shaped or sigmoid curve is obtained. It consists of four parts-lag phase, log phase (exponential phase) phase of diminishing growth and stationary phase (steady growth for organs or organisms of indefinite growth).

Answer: (a)

Ethylene is a gaseous hormone produced by the ripened fruits. It also helps in the ripening of other unripened fruits.

Answer: (a)

Answer: (b)

Answer: (b)

Gibberellins promote seed germination. Gibberellins are weakly acidic growth hormones having ring structure and cause cell elongation of intact plants in general and increased internodal length of genetically dwarfed plants. Gibberellins are synthesized in the apical shoot buds, root tips and developing seeds. During seed germination, especially of cereals gibberellin stimulates the production of some messenger RNAs and then hydrolytic enzymes like amylases, lipases, proteases. The enzymes solubilize the reserve food of the seed.

Answer: (a)

Answer: (c)

Answer: (a)

Answer: (b)

Answer: (c)

Answer: (a)

When terminal bud of a plant is removed, apicaldominance is removed and thus lateral buds will grow.

Answer: (d)

Phytochrome is a chromoprotein i.e., plant pigment that can detect the presence or absence of light and is involved in regulating many processes that are linked to day length (photoperiod), such as seed germination and initiation of flowering. It consists of a light detecting portion, called a chromophore, linked to a small protein and exists in two inter-convertible forms with different physical properties.