Botany MCQs for NEET — Practice Questions with Answers

The Bt toxin produced by Bacillus thuringiensis (Bt) is a protein that becomes toxic when ingested by insects. After ingestion, the toxin is activated in the alkaline conditions of the insect's gut, binds to the gut wall, creates pores, and ultimately leads to the insect's death. This makes option o4 correct.

By Biochemical Oxygen Demand (BOD) presence of organic matter in water can be measured.

To match the terms correctly: (R) Encilage is food for cattle (i), (Q) Flocks are associations of bacteria and filaments of mold in water (ii), (P) BOD is a measure of the organic matter in water (iii), and (S) Biogas is produced through anaerobic metabolism on bio-waste (iv). Therefore, the correct match is option o1: (R-i) (Q-ii) (P-iii) (S-iv).

To match the terms correctly: (P) Rhizobium is associated with leguminous plants (i), (Q) Anabaena is an autotroph and a nitrogen-fixing cyanobacterium (ii), (R) Azotobacter is a free-living nitrogen-fixing bacterium (iii), and (S) Glomus is involved in phosphorus absorption (iv). Therefore, the correct match is option o1: (P-i) (Q-ii) (R-iii) (S-iv).

Both the assertion and the reason are true, and the reason correctly explains the assertion. Cattle dung is indeed used to produce biogas because it contains a large number of methanogenic bacteria. These bacteria break down organic matter anaerobically to produce methane, which is a major component of biogas.

Photophosphorylation is the process by which ATP is formed utilizing the energy of sunlight during photosynthesis. This process occurs in the chloroplasts of plant cells.

DNA replication occurs during the S phase (Synthesis phase) of the cell cycle. In this phase, the cell synthesizes a complete copy of the DNA in its nucleus, ensuring that each daughter cell will have a complete set of chromosomes after cell division.

A cataract is a clouding of the eye's lens and is not hereditary. It can be caused by aging, injury, or other conditions, but it is not passed down from parents to offspring like sickle cell anemia, hemophilia, or color blindness.