CBSE 12TH BIOLOGY - Online Test
Q1. The first antibiotic was discovered by
Answer : Option D
Explaination / Solution:
Penicillin from fungus Penicilliumnotatum, the first true antibiotic, was discovered by Alexander Fleming, Professor of Bacteriology at St. Mary's Hospital in London in 1928.
Q2. Beadle and Tatum showed that each kind of mutant bread mould they studied lacked a specific enzyme. Their experiments demonstrated that
Answer : Option B
Explaination / Solution:
Sir Archibald Garrod, a British medical doctor, was the first to suggest that genes were connected to enzymes.
George W. Beadle (1903-1989) and Edward L. Tatum (1909-1975) show genes direct the synthesis of enzymes that control metabolic processes using genetic and biochemical studies of the bread mold Neurospora.
Q3. When the main pool is located in the soil and rocks, that nutrient cycle is called
Answer : Option D
Explaination / Solution:
The nutrient cycle in which reservoir is located in earth crust is called sedimentary nutrient cycle. So, soil and rock based nutrient cycles are example of sedimentary nutrient cycle.
Q4. Which of the following variety of wheat is resistant to leaf and strip rust and hill bunt disease?
Answer : Option D
Explaination / Solution:
Himgiri wheat variety is resistant to disease like leaf and strip rust and hill bunt disease that cause great loss of productivity due to loss of plant parts.
Q5. Tropical Botanical garden and research institute is situated at
Answer : Option D
Explaination / Solution:
Tropical Botanic Garden and Research Institute (TBGRI) is an autonomous institute established by the Government of Kerala in 1979 at Thiruvanantapuram, Kerala.
The institute conducts research in Conservation Biology, Biotechnology, Plant Taxonomy, Microbiology, Phytopharmocology, Ethnomedicine and Ethopharmacology for plant improvement and utilisation.
TBGRI also undertakes research on medicinal plants, ornamental plants and various introduced plants of economic or aesthetic value. The institute conserves the largest number of plant species among the botanical gardens in Asia
Q6. Which one shows meiosis
Answer : Option A
Explaination / Solution:
Anther produces pollen grains by the process of meiosis in which four microspores are produced by single microspore mother cell. The number of chromosome reduces to half.
Q7. Corpus spongiosum is found in
Answer : Option D
Explaination / Solution:
The corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis. These tissues get filled with blood during copulation.
Q8. Inheritance of skin colour in human being is an example of
Answer : Option D
Explaination / Solution:
Skin colour in human being is controlled by many genes so it is an example of polygenic inheritance.
Q9. Masses of bacteria associated with fungal filaments to form mesh like structures is called
Answer : Option D
Explaination / Solution:
The masses of bacterium associated with fungal filaments to form mess like structure is called flocs. Flocs are used to remove organic wastes from waste water.
Q10. Oil spills prevent oxygenation of water so they are :
Answer : Option C
Explaination / Solution:
Physical pollution is the introduction of discarded materials into the environment. Physical pollution is what you might refer to as trash and is the direct result of human actions.
In other words, nature does not produce physical pollution because in natural systems, all byproducts or wastes are eventually recycled back into the environment. For example, in nature, a fallen tree will degrade and eventually return nutrients to the soil..
Oil splits over the water bodies is the result of human activities. It prevents the oxygenation of water. It is physical pollutants.
