Biology MCQ Question with Answer

Explanation: Nails, hoofs and horns are made up of keratin tissue. Keratin is a fibrous structural protein. It protects the outermost layer of organisms from damage.

Explanation: Green manure is formed by decomposing with leguminous plants. The leguminous plant forms the root nodules which helps in nitrogen fixation with the help of Nitrogen fixation bacteria. Thus green manure improves the soil fertility in organic farming.

Explanation: Octopus belongs to Mollusca. Jellyfish belongs to Coelenterata. Silverfish belongs to Arthropoda. Bombay Duck belongs to Pisces.

Explanation: Python or some species of python is a non-venomous snake. All the other snakes are poisonous.

Explanation: Cholera, Typhoid and Jaundice are water-born diseases. In shallow hand pumps, there is the possibility of microbial contamination ( bacteria) to water. But fluorosis occurs due to an excess amount of fluoride found in water.

Explanation: Nephrons are the structural & functional units of Kidneys. The nephron is segmented into 4 main parts Bowan’s capsule, Glomerulus apparatus, tubular part and collecting duct. Around 2 mn Nephrons are present in both kidneys.

Explanation: Watson and Crick primarily explained the DNA double-helical structure by the X-Ray crystallography method.

Explanation: Cell is the fundamental unit of life. It is controlled by Nucleus. Nucleus control all metabolic reactions of the cells.

Explanation: Ostrich is the largest flightless bird that can run at a speed of 70 km/hr. The scientific name of the ostrich is Struthio camelus

Explanation: Night blindness is medically known as Nyctalopia in which the rod cells in the retina gradually lose their ability to respond to the light. Vitamin-A deficiency in the diet of humans is one of the causes of night blindness. ​​Scurvy is caused by deficiency of vitamin C, Beri-Beri is caused by deficiency of vitamin B1 and weakness, muscle degradation is caused by deficiency of vitamin E.

Explanation: Arthropoda is an invertebrate animal having an exoskeleton (external skeleton), a segmented body, and paired jointed appendages.

Explanation: If vitamins A and D are taken in excess amounts they are stored in the body as hypervitaminosis. The excess amount of vitamin-A leads to abnormal softening of skull bone, blurred vision, liver damage etc. Excess of vitamin D leads to over calcification of bones, heart & kidneys.

Explanation: Plaster of Paris is a hard white substance made by the addition of water to powered and partly dehydrated gypsum. It is used for holding broken bones.

Explanation: Both the statement is correct.

HCl is secreted, providing an acid medium for pepsin action and kill most bacteria and helps in the digestion of food. When the food enters the duodenum (small intestine), secretin is produced by the intestine that stimulates the pancreas for pancreatic juice secretion.

Enterogastrone is produced in the small intestine.

Explanation: Typhoid is caused by the bacteria Salmonella typhi. It is ingested through contaminated water or food Symptoms include abdominal pain, constipation and diarrhoea. It affects the digestive system. Treatment of disease is done by drugs such as azithromycin, fluoroquinolones and chloramphenicol.

Explanation: Benzene is a highly toxic substance that can affect DNA, causing chromosome changes and abnormal cell function. Long term exposure to benzene causes the bone marrow to produce fewer blood cells. This results in anaemia or low red blood cell count. The most serious effect of benzene poisoning is leukaemia, which is a cancer of blood-producing tissues.

Explanation: Tortoise has a maximum life span. Tortoise can live up to 250 years.

Explanation: The protocol was initially adopted on 11^th December 1997. But it entered into force on 16^th February 2005, after Kyoto, Japan. So, it is called the Kyoto protocol.

Kyoto protocol deals with reducing the greenhouse gases emission to a level at least 5% below the 1990 level. Methane is a more effective or harmful greenhouse gas than carbon dioxide.

Explanation:  When the osmotic pressure outside the red blood cells is the same as the pressure inside the cells, the solution is isotonic with respect to the cytoplasm. This is the usual condition of red blood cells in plasma. Hence the cells do not shrink.

Explanation: The pheromones are specialized hormones secreted mostly lower organisms to attract the member of same species. The ants and cockroaches show the best example in this regard. Sometimes it is released by some fungi as well.

Explanation: The theory of mutation is postulated by de Vries. The theory of evolution is by Charl’s Darwin. Operon concept is given by Jacob and Monad. One gene and one enzyme hypothesis are proposed by Beadle and Tatum.

Explanation: The sexes are separate except few echinoderm species. There is no sexual dimorphism. Fertilization is external and few forms are viviparous.

Explanation: Meningitis is an infection of the protective membrane that surrounds the brain and spinal cord. The membrane or meningitis membranes are named dura mater, arachnoids and Pia mater.