CBSE 12TH BIOLOGY - Online Test
Q1. The property of Taq polymerase explored in PCR is
Answer : Option D
Explaination / Solution:
Taq polymerase is a thermostable DNA polymerase. Taq polymerase is an enzyme that copies DNA. It is isolated from a heat-loving bacterium that is naturally found in hot springs, so the enzyme doesn't break down at the high temperatures necessary for copying DNA using a polymerase chain reaction.
Q2. Lichen can be used as industrial pollution indicators because
Answer : Option C
Explaination / Solution:
The hardy lichens are useful bioindicators for air pollution, espeially sulfur dioxide pollution, since they derive their water and essential nutrients mainly from the atmosphere rather than from the soil. It also helps that they are able to react to air pollutants all year round. Lichens are symbiotic association between algae and fungi.
Q3. The internal buds produced by Spongila is known as
Answer : Option A
Explaination / Solution:
Gemmules are internal buds found in sponges and are involved in asexual reproduction. It is an asexually reproduced mass of cells, that is capable of developing into a new organism i.e., an adult sponge
Q4. Universal non-polluting source of energy is
Answer : Option A
Explaination / Solution:
Universal non-polluting source of energy is sun. All the sources of energy are directly and indirectly derived from sun including fossil fuels.
Q5. Rosie’s milk is enriched nutritionally as it has
Answer : Option D
Explaination / Solution:
The first transgenic cow Rosie produced human protein enriched milk. The milk contained Alpha lactalbumin which was nutrionally more balanced than normal cow milk for babies.
Q6. In a population, unrestricted reproductive capacity is called as
Answer : Option A
Explaination / Solution:
Unrestricted reproductive capacity of a population is called biotic potential. Having coitus with opposite partners may leads to pregnancy and cause a number of problems to individual as well as society.
Q7. Double fertilisation is fusion of
Answer : Option D
Explaination / Solution:
Double fertilisation is the fusion of Syngamy and triple fission. One male gamete fertilizes the egg and other male gamete fuse with two polar nuclei called triple fission.
Q8. Phytophagous insects will be categorized as
Answer : Option B
Explaination / Solution:
The insect that feeds on plant sap and other parts of plants are called phytophagous. Phytophagous insects will be similar to predators and plants acts as prey.
Q9. Choose the wrong statement regarding AIDS
Answer : Option D
Explaination / Solution:
AIDS is caused by human immune virus (HIV). HIV infects and kills B-lymphocytes. In this disease viral RNA genome is converted into DNA copy by reverse transcriptase.
Q10. Whose experiments cracked the DNA and discovered unequivocally that a genetic code is a ‘‘triplet’’?
Answer : Option D
Explaination / Solution:
The Nirenberg and Matthaei experiment was a scientific experiment performed on May 15, 1961, by Marshall W. Nirenberg and his post doctoral fellow, J. Heinrich Matthaei. The experiment deciphered the first of the 64 triplet codons in the genetic code by using nucleic acid homopolymers to translate specific amino acids and discovered that genetic code is triplet
