Biology: Zoology: UPSC Previous Year Questions (Science and Technology)

Explanation

Statement 1 is correct: Vitamin A is essential for maintaining healthy tear production and eye lubrication. Its deficiency can cause xerophthalmia, leading to dryness in the conjunctiva and cornea due to impaired lacrimal gland function. If left untreated, it can result in severe eye damage and vision impairment.

Statement 2 is correct: Vitamin B1 (thiamine) plays a crucial role in energy metabolism and nerve function. Its deficiency leads to beriberi, which occurs in two forms:

Wet beriberi affects the cardiovascular system, potentially causing heart enlargement, rapid heartbeat, and heart failure. Dry beriberi impacts the nervous system, leading to muscle weakness, nerve damage, and digestive issues such as indigestion.

Statement 3 is correct: A lack of Vitamin C results in scurvy, characterized by muscle pain, joint discomfort, and fatigue. Since Vitamin C is essential for collagen synthesis and its deficiency weakens connective tissues, leading to pain, fragile blood vessels, and slow wound healing.

Statement 4 is correct: Vitamin D is vital for calcium absorption in the intestines. Due to its deficiency calcium absorption decreases which leads to low blood calcium levels. The body compensates by increasing parathyroid hormone (PTH) secretion which draws calcium from bones. Without sufficient Vitamin D the kidneys may excrete more calcium in urine, leading to weakened bones and risk of osteoporosis.

Explanation

Insulin is a protein-based hormone produced by beta cells in the pancreas, specifically in the Islets of Langerhans. It consists of two peptide chains (A and B) connected by disulfide bonds and plays a crucial role in regulating blood glucose levels. By promoting glucose uptake in cells, it helps maintain energy balance and prevents hyperglycemia. Insulin was first discovered by Frederick Banting and Charles Best in 1921. It is the first recombinant DNA-based drug approved for human use.

Explanation

Statement 1 is incorrect: Pangolins (scaly anteaters) are fascinating toothless mammals covered in protective keratin scales. They use their long, sticky tongues to capture ants and termites, making them nature’s pest controllers. India is home to two species of pangolins:

Indian Pangolin (Manis crassicaudata) is found across most parts of India, except for the northeastern states. Chinese Pangolin (Manis pentadactyla) inhabits the forests of northeast India, including Assam, Arunachal Pradesh, and Meghalaya. Pangolins are the most trafficked mammals in the world due to demand for their scales and meat.

Statement 2 is correct: Hoolock Gibbon is India’s only ape species and is a true acrobat of the rainforest. Unlike monkeys, gibbons lack tails and move gracefully through the trees using brachiation (swinging from branch to branch). These lesser apes are found in Northeast India, especially in Assam (Hoollongapar Gibbon Sanctuary) Arunachal Pradesh, Meghalaya, Mizoram, Manipur, Nagaland and Tripura. Hoolock gibbons are known for their melodious calls, which echo through the dense forests. Sadly, habitat destruction and deforestation have put them at risk.

Explanation

The term "long bone" refers to bones that are longer than they are wide such as the femur and humerus. The bone marrow within these long bones is a primary site for lymphocyte production. This process is known as lymphopoiesis and involves the differentiation of hematopoietic stem cells into various lymphocyte types such as B cells, T cells, and natural killer cells.

Explanation

Statement 1 is correct: The femur, or thigh bone is the longest and strongest bone in the human body. It stretches from the hip to the knee and provides crucial support and stability, allowing us to walk, run, and jump. The femur can withstand forces up to 816-1,134 kg before breaking, making it one of the strongest structures in our skeletal system.

Statement 2 is correct: Cholera is a severe bacterial infection caused by Vibrio cholerae. It spreads mainly through contaminated water or food, leading to acute diarrhea and dehydration. In extreme cases a person with can lose up to 20 liters of fluid per day making rapid treatment with rehydration therapy essential.

Statement 3 is incorrect: Athlete’s foot (Tinea Pedis) is not caused by a virus, but by fungal infection. Dermatophyte fungi thrive in warm, damp environments like locker rooms, swimming pools, and sweaty shoes. The infection causes itchy, peeling, and cracked skin between the toes, making it a common concern among athletes and hence the name.