Botany MCQs for NEET — Practice Questions with Answers

The correct sequence of the cell cycle is G1, S, G2, M. In the G1 phase, the cell grows and performs its normal functions. In the S phase, DNA replication occurs. During the G2 phase, the cell prepares for mitosis by producing the proteins and organelles necessary for cell division. Finally, in the M phase, mitosis and cytokinesis occur, resulting in two daughter cells.

GEMMAE ARE PRODUCED IN GEMMAE CUPS WHICH ARE THE ASEXUAL STRUCTURES IN BRYOPHYTES

Microtubules are an essential component of the cell's cytoskeleton and play a crucial role during mitosis in the separation of chromosomes. They form the spindle fibers that ensure each daughter cell receives an equal and precise set of chromosomes. Therefore, the correct option is 'Microtubules are involved in precise separate set of chromosomes get into each daughter cells.'

Chromosomes are most distinctly visible and can be easily counted during metaphase. During this phase, the chromosomes align at the metaphase plate, making it easier to observe and count them. Hence, the correct option is 'Metaphase.'

Karyokinesis refers to the overall changes occurring in the nucleus during cell division. This includes the processes of prophase, metaphase, anaphase, and telophase, where the nucleus divides to form two daughter nuclei.

Prophase-I is the longest phase of meiotic division. During this phase, homologous chromosomes pair up and exchange genetic material through a process called crossing over. This phase is crucial for genetic diversity.

In the Diplotene stage of meiosis, homologous chromosomes begin to separate due to repulsion but are still held together by chiasmata, which are the sites where crossing over has occurred.

Meiosis is significant for sexual reproduction because it reduces the chromosome number by half, ensuring that when gametes fuse during fertilization, the resulting zygote has the correct diploid number of chromosomes. This process also introduces genetic variation.

During sexual reproduction in angiosperms, meiosis occurs in microspore and megaspore mother cells. In one meiotic division, one microspore mother cell in the anther forms 4 microspores, each of which develops as a pollen grain. When there are 100 pollen grains, the meiotic divisions which will be required are 100/4= 25. The number of meiotic divisions for 100 pollen grains is 25.