Botany MCQs for NEET — Practice Questions with Answers

The NCERT mentions that 'plants can show mitotic divisions in both haploid and diploid cells.' If a haploid cell (n chromosomes, C DNA in G1) undergoes mitosis, it first undergoes S phase increasing DNA content to 2C while chromosome number remains n. Then, during mitosis (equational division), the sister chromatids separate, and the cell divides, resulting in daughter cells that are also haploid (n chromosomes) and have the original DNA content (C). Therefore, the resulting daughter cells will have n chromosomes and C DNA content.

In G1, the cell has 2n chromosomes and 2C DNA. After S phase and until metaphase, the cell maintains 2n chromosomes (each with two chromatids) and 4C DNA. During anaphase, the centromeres split, and sister chromatids separate, moving to opposite poles. At this point, each chromatid is considered an individual chromosome. Therefore, temporarily, the chromosome number doubles to 4n, and the DNA content remains 4C in the entire cell during anaphase, before cytokinesis fully separates them.

According to the NCERT text, 'In both parasitism and predation only one species benefits (parasite and predator, respectively) and the interaction is detrimental to the other species (host and prey, respectively).' Therefore, parasitism fits this description.

The NCERT states, 'Their morphological and anatomical features are greatly simplified while emphasising their reproductive potential.' This highlights the simplification of their physical structures due to extreme specialization as endoparasites.

The NCERT text explicitly defines brood parasitism: 'Brood parasitism in birds is a fascinating example of parasitism in which the parasitic bird lays its eggs in the nest of its host and lets the host incubate them.'

Under Sporozoans, the NCERT states, 'The most notorious is Plasmodium (malarial parasite) which causes malaria, a disease which has a staggering effect on human population.'

The NCERT text mentions, 'White spots seen on mustard leaves are due to a parasitic fungus.' The fungi constitute a unique kingdom of heterotrophic organisms.

The summary explicitly states, 'predation and parasitism (one benefits and the other suffers).' Therefore, 'one organism is benefited, and the other is harmed' accurately describes parasitism.

The NCERT defines endoparasites as 'those that live inside the host body at different sites (liver, kidney, lungs, red blood cells, etc.).' Plasmodium (malarial parasite) is an example of such and is explicitly mentioned as living in the red blood cells, causing malaria.

The NCERT states, 'Predation, parasitism and commensalism share a common characteristic – the interacting species live closely together.'