All Free Biology MCQs with Answers

• A. Maize
• B. Rice
• C. Wheat
• D. Bajra.

Explanation: Green Revolution was one of the major tasks for agricultural scientists in India to produce sufficient food for an increasing population. Better yielding semi­ dwarf varieties of rice, "Jaya" and "Ratna" were developed for Green Revolution.

• A. Chilli
• B. Maize
• C. Sugarcane
• D. Wheat.

Explanation: 'Himgiri' is a variety of wheat. HS­-375 and HS375 are the two common varieties of Himgiri. HS­ -375 is produced on irrigated/rain­fed area. It is of medium fertility and sown hybrid of Himgiri, while HS375 is produced on very high altitude i.e., in the Northern Himalayan and Garhwal region. 'Himgiri' is resistant to leaf and stripe rust and hill bunt diseases.

• A. Somatic hybridisation
• B. Biofortification
• C. Biomagnification
• D. Micropropagation.

Explanation: Breeding of crops with higher levels of vitamins and minerals or higher protein and healthier fats is called biofortification. This is the most practical aspect to improve the health of the people.

• A. Biodiesel production
• B. Seedless fruit production
• C. Energy production from sewage
• D. Gene transfer without a vector.

Explanation: Direct gene transfer is the transfer of naked DNA into plant cells, but the presence of a rigid plant cell wall acts as a barrier to uptake. Therefore, protoplasts are the favoured target for direct gene transfer. Polyethylene glycol mediated DNA uptake is a direct gene transfer method that utilizes the interaction between PEG, naked DNA, salts and the protoplast membrane to effect transport of the DNA into the cytoplasm

• A. Plant breeding
• B. Irradiation
• C. genetic Engineering
• D. Tissue culture.

Explanation: Genetic variation present among plant cells during tissue culture is called somaclonal variation. The term somaclonal variation is also used for the genetic variation present in plants regenerated from a single culture. This variation has been used to develop several useful varieties.

• A. Haploids are more abundant in nature than diploids
• B. All mutations, whether dominant or recessive are expressed in haploids
• C. Haploids are reproductively more stable than diploids
• D. Mutagens penetrate in haploids more effectively than in diploids.

Explanation: Haploid plants, are always pure because they possess only one set of chromosomes. So, the mutations are expressed very easily in haploid plants as compared to diploid plants.

• A. Loose smut of wheat
• B. Black rust of wheat
• C. Bacterial leaf blight of rice
• D. Downy mildew of grapes

Explanation: The first inorganic fungicide was developed by R.M.A. Millardet (1882) against downy mildew (Plasmopara viticola) of grape­-vine at the University of Bordeaux and is commonly known as Bordeaux mixture. It consists of copper sulphate, lime and water.

• A. 3 and 4
• B. 1 and 4
• C. 2 and 3
• D. 1 and 2

Explanation: Bacterial blight of chickpea is caused by bacterium Xanthomonas campestris. The stems and the leaves of the infected plant give a blighted or burnt up appearance. Control measures include rogueing, 3­- year crop rotation, disease free seeds, spray of copper fungicides (Bordeaux mixture) and antibiotics besides sowing disease-resistant varieties.

• A. Higher levels of cortisone
• B. Lower levels of blood testosterone
• C. Lower levels of adrenaline/noradrenaline in its blood
• D. Higher levels of thyroxine.

Explanation: A bullock is a castrated bull. Bulls are castrated to make them more meek and docile. Castration is any action, surgical, chemical, or otherwise, by which a male loses the functions of the testes or a female loses the functions of the ovaries. Castration is the removal or destruction of one or both testicles and results in sterility, decreased sexual desire, and inhibition of secondary sex characteristics. It is performed for the purpose of improving the quality of meat and decreasing the aggressiveness of farm animals; in pet animals it prevents unwanted mating behaviour, reproduction, and wandering.

• A. Coryza
• B. Newcastle disease
• C. Pasteurellosis
• D. Salmonellosis

Explanation: New castle disease is a highly contagious zoonoic bird disease affecting many domestic and wild avian species.The causal agent, New castle disease virus (NDV), is a negative­sense single­ stranded RNA virus. Transmission occurs by exposure to faecal and other excretions from infected birds, and through contact with contaminated feed, water, equipment and clothing. Signs of infection with NDV vary greatly depending on factors such as the strain of virus and the health, age and species of the host. They can include respiratory signs (gasping, coughing), nervous signs (depression, inappetence, drooping wings, paralysis), swelling of the eyes and neck, diarrhoea, rough or thin­shelled aggs and reduced egg production.