Question 1

Which of the following is not true of the first cell division of a plant embryo?&#10;A) It establishes the apical-basal axis of the plant&#10;B) It gives rise to a suspensor&#10;C) It is parallel to the long axis&#10;D) It gives rise to a proembryo

Accepted Answer

The first cell division of a plant embryo is typically perpendicular to the long axis, not parallel. This division is crucial for establishing the apical-basal axis of the plant, giving rise to structures such as the suspensor and proembryo.

Question 2

At which stage do cotyledons start to develop wing-like structures?&#10;A) Heart stage&#10;B) Globular stage&#10;C) Octant stage&#10;D) Triangular stage

Accepted Answer

Cotyledons start to develop wing-like structures at the heart stage, which is a phase in the development of the embryo of a plant.

Question 3

Which of the following is not true of auxin?&#10;A) Auxin functions as a diffusible extracellular signaling factor&#10;B) It establishes the apical-basal axis&#10;C) It is actively transported from the basal cell into the apical cell&#10;D) The concentration gradient of auxin is necessary for specifying different cell fates

Accepted Answer

Auxin functions as a plant hormone that is primarily transported within the plant rather than acting as a diffusible extracellular signaling factor. Its role involves internal signaling mechanisms that regulate various aspects of plant growth and development, rather than functioning in an extracellular manner.

Question 4

Which of the following is not a correct interpretation of a differentiated somatic cell's ability to regenerate a new plant?&#10;A) Maternal determinants are of little or no importance for plant embryogenesis&#10;B) The fate of many cells in the adult plant body is not fully determined&#10;C) This opens up avenues for creating transgenic plants&#10;D) Many adult plant cells have lost their potential

Accepted Answer

Many adult plant cells retain the ability to regenerate into a whole plant, indicating they have not lost their potential.

Question 5

Which of the following is the type of meristem of the axillary bud near the base of a leaf?&#10;A) Shoot apical meristem&#10;B) Lateral shoot meristem&#10;C) Inflorescence meristem&#10;D) Floral meristem

Accepted Answer

Lateral shoot meristem is responsible for the growth and development of axillary buds near the base of a leaf, leading to the formation of lateral shoots or branches.

Question 6

A diffusible inhibitor emanating from the shoot apex inhibits the development of lateral buds below the apical bud. What is this inhibitory effect called?&#10;A) Lateral inhibition&#10;B) Apical dominance&#10;C) Lateral dominance&#10;D) Apex inhibition

Accepted Answer

Apical dominance is the phenomenon where the main, central stem of the plant is dominant over (i.e., grows more strongly than) other side stems; it is caused by the plant hormone auxin produced in the shoot apex (tip of the plant or main stem). This inhibits the growth of lateral buds into branches.

Question 7

What is the name of the slowly dividing, self-renewing stem cells of the central zone within a meristem?&#10;A) Centrals&#10;B) Peripherals&#10;C) Initials&#10;D) Apicals

Accepted Answer

Initials are the slowly dividing, self-renewing stem cells found in the central zone of a meristem. They are responsible for the meristem's ability to continuously generate new cells for plant growth.

Question 8

Which of the following axis is represented by the line between the leaf base to the leaf tip?&#10;A) Proximo-distal&#10;B) Adaxial-abaxial&#10;C) Apical-basal&#10;D) Dorso-ventral

Accepted Answer

The proximo-distal axis refers to the direction from the base (proximal end) of a structure to its tip (distal end), which in the context of a leaf, is from the leaf base to the leaf tip.

Question 9

Which of the following is not true of homeotic floral mutations in Arabidopsis?&#10;A) One class of mutants affect whorls 1 and 2&#10;B) One class of mutants affect whorls 3 and 4&#10;C) One class of mutants affect whorls 2 and 3&#10;D) One class of mutants affect whorls 1 and 4

Accepted Answer

Homeotic floral mutations in Arabidopsis typically affect adjacent whorls, such as 1 and 2, 2 and 3, or 3 and 4, following the ABC model of flower development. There is no class of homeotic mutants known to specifically affect non-adjacent whorls like 1 and 4 directly, making option D incorrect.

Question 10

What kinds of proteins do floral organ identity genes encode?&#10;A) Intercellular signaling ligands&#10;B) Cell-adhesion proteins&#10;C) Cell-surface receptors&#10;D) Transcription factors

Accepted Answer

Floral organ identity genes encode transcription factors, which are proteins that regulate the expression of other genes by binding to specific DNA sequences. These transcription factors are crucial in determining the identity and development of the various floral organs.

Deck 13: Plant Life Cycle and Development