CBSE 12TH BIOLOGY - Online Test
Q1. Which of the following is a biosphere reserve in eastern Himalayan regions:
Answer : Option D
Explaination / Solution:
The Dihang-Dibang Biosphere Reserve is situated in the districts of West Siang, Upper Siang and Dibang valley of Arunachel Pradesh in eastern Himalayan range. This reserve is almost totally forested, having villages and cultivated lands located on lower slopes and terrace edging the major river systems. The reserve is the last stronghold for many Himalayan species.
Q2. The inner most wall layer of microsporangium is called as
Answer : Option D
Explaination / Solution:
Microsporangium is covered by a number of layers. The outer layer or integuments surround the tepetum. The tepetum provide nutrients to growing microspores that leads to pollen grains.
Q3. Which pair is similar
Answer : Option C
Explaination / Solution:
Graafian follicle changes into corpus leteum as egg is released from it during ovulation. Corpus leteum release hormone called androgen.
Q4. Which of the following is an example of co-dominance?
Answer : Option A
Explaination / Solution:
Co-dominance is the phenomenon that deviates from Mendel’s law of inheritance. Both the alleles appear in offspring instead of one as in Mendel’s experiment. ABO blood grouping in human being is example of co-dominance in which both IA and IB appear simultaneously to form AB blood type.
Q5. The amount of oxygen that would be consumed if all the organic matter in one liter of water were oxidized by bacteria is called
Answer : Option D
Explaination / Solution:
Biological Oxygen Demand is the amount of oxygen that would be consumed if all the organic matter in one liter of water are oxidized by bacteria. it is used as indicator of water pollution. More the value of BOD higher the water polluted.
Q6. That species which is found in highest concentration within a polluted water reservoir is called :
Answer : Option A
Explaination / Solution:
A number of organisms grow in polluted water. The species whose concentration is highest in polluted water is celled as index species as this species indicate the presence of particular kinds of pollutant in water.
Q7. Parthenogenesis is the development of unfertilized ovum into a fully formed haploid organism. Natural parthenogenesis is found in
Answer : Option C
Explaination / Solution:
Development of individual from unfertilized ovum is called parthenogenesis. The individual is haploid as no fusion of gametes occurs. Honey bee is of three kinds namely queen, drone and worker. Workers are produced parthenogenetically.
Q8. Restriction enzymes belongs to a larger class of enzymes called
Answer : Option B
Explaination / Solution:
A restriction enzyme (or restriction endonucleases) recognizes a specific base pair sequence in DNA called a restriction site and cleaves the DNA (hydrolyses the phosphodiester backbones) within the sequence. Restriction enzymes are widely found in prokaryotes and provide protection to the host cell by destroying foreign DNA that makes entry to it. It acts as a part of defense mechanism.
Restriction enzymes belong to a larger class of enzymes called nucleases. They are of two types: endonucleases and exonucleases.
Q9. The experiment to show the production of mice in 21 days from a dirty shirt placed in Contact with kernels of wheat was carried out by ______.
Answer : Option C
Explaination / Solution:
The first experiments to prove the spontaneous generation theory were done in the XVII century and a doctor called Jean Baptiste Van Helmont declared he had performed a unique experiment: he placed a dirty shirt together with some wheat and according to him, mice were born 21 days later.
According to the Doctor the sweat in the shirt was the active element which gave life to the inert matter.
Q10. ELISA is
Answer : Option D
Explaination / Solution:
An enzyme-linked immunosorbent assay, also called ELISA or EIA, is a test that detects and measures antibodies in your blood. This test can be used to determine if you have antibodies related to certain infectious conditions. It is used to detected the disease at early stage.
