NEET Practice Questions (MCQs) with Answers & Solutions

Mountain sickness, also known as altitude sickness, occurs due to the decreased partial pressure of oxygen at high altitudes. This lower oxygen availability leads to hypoxia, causing symptoms like headaches, dizziness, and nausea. The body struggles to get enough oxygen to its tissues, leading to the symptoms of mountain sickness.

During strenuous exercise, the body's demand for energy increases. When oxygen is limited, glucose is anaerobically converted into lactic acid. This process helps to quickly generate ATP, the energy currency of the cell, although it results in the accumulation of lactic acid in muscles, causing fatigue.

Silicosis is associated with the spreading of fibrous tissue in the lungs (P 1). Emphysema is characterized by little alveolar elasticity (Q 2). Asthma involves the muscles of the wall of the trachea (R 3). Bronchitis is marked by a burning sensation of the bronchus (S 4). Therefore, the correct pairs are P 1, Q 2, R 3, S 4.

The zygote is the initial cell formed when two gamete cells are joined by means of sexual reproduction. It is responsible for the beginning of the life of organisms as it undergoes multiple cell divisions and differentiation to form a complete organism.

Rudolf Virchow proposed that new cells arise through the division of pre-existing cells. This concept is a fundamental principle of cell theory.

Mycoplasma is known to be the smallest living cell. It lacks a cell wall and can survive without oxygen. Bacteria, yeast, and blue-green algae are larger in comparison.

A polysome, or polyribosome, is a cluster of ribosomes bound to an mRNA molecule. This structure allows for the simultaneous translation of a single mRNA by multiple ribosomes, enhancing protein synthesis efficiency.

F-particles, also known as ATP synthase particles, are located on the cristae of mitochondria. These enzyme complexes are crucial for ATP production during oxidative phosphorylation.

Microfilaments are primarily composed of actin, which is a type of protein. Actin filaments are part of the cytoskeleton and play a key role in maintaining the cell's shape, enabling cellular movements, and participating in various cellular processes.