AIPMT 2011 Mains question paper with solutions

1. Recall the muscles involved in normal breathing. Breathing normally involves both the diaphragm (a dome-shaped muscle below the lungs) and the external intercostal muscles (which move the ribs).

2. Understand diaphragmatic breathing. With conscious effort, a person can choose to breathe using only the diaphragm, moving it up and down without involving rib movement at all — this is commonly known as diaphragmatic (belly) breathing.

This technique is often practiced in yoga and relaxation exercises.

3. Eliminate the incorrect options. Exhaled air always contains some oxygen (never zero), air cannot normally be exhaled through the Eustachian tube with nose and mouth closed under typical conditions, and lungs can never be made fully empty because residual volume always remains, no matter how forcefully one exhales.

4. Conclusion. It is genuinely possible to consciously breathe using only diaphragm movement, without moving the ribs.

Hence, the answer is C.

1. Understand essential elements - An element is considered essential for plants if it is directly involved in plant metabolism and its deficiency cannot be fully replaced by another element.

2. Check the given elements - Iron and Manganese are recognised micronutrients, while Phosphorus is a well-known macronutrient — all three are essential for normal plant growth.

3. Why Cadmium is different - Cadmium is not required by plants for any known metabolic function. In fact, it is often considered a toxic heavy metal that can harm plants when present in excess, rather than being an essential nutrient.

4. Conclusion - Hence, the element that is not essential for plants is Cadmium, so the answer is Option C.

1. Background: Bacillus thuringiensis produces crystal proteins during sporulation, which act as insecticidal toxins once ingested by a susceptible insect.

2. After the insect ingests the spores, this protein is activated by the high alkaline pH of the gut, not an acidic pH, so option A is incorrect.

3. Once activated, the toxin performs its lethal action by binding to the epithelial cells of the midgut of the insect, destroying these cells and ultimately killing the pest.

4. While it is true that the toxin is coded by genes named cry, and the bacterium itself is resistant to its own toxin, the question specifically asks what the protein does, and the defining, most complete correct action described among the options is its lethal binding to midgut cells.

5. Hence, the correct answer is B: binds with epithelial cells of midgut of the insect pest ultimately killing it.