CBSE 12TH BIOLOGY - Online Test
Q1.
Genetic and physical map of genome was generated using information on
a. Polymorphism of restriction endonuclease recognition sites.
b. Repetitive DNA sequence called microsatellites.
Answer : Option C
Explaination / Solution:
Genetic and physical map of genome was generated using information on polymorphism of restriction endonuclease recognition sites and repetitive DNA sequence called microsatellites.
Q2. Which one is correctly matched pair
Answer : Option B
Explaination / Solution:
Transfer of male gamete into female genital tract takes place during sexual intercourse, which is also called as coitus. Clitoris is the part of female reproductive system, colostrum is first milk secreted from mammary gland.
Q3. Genetic drift
Answer : Option B
Explaination / Solution:
Genetic drift is a mechanism of evolution in which allele frequencies of a population change randomly over generations due to chance (sampling error). Genetic drift occurs in all populations of non-infinite size, but its effects are strongest in small populations.
Q4. Which of the following is not a cause of male sterility?
Answer : Option C
Explaination / Solution:
Male sterility is mainly due to less number of sperm count or sperms motility is very less to fertile the ovum. The first case is called oligospermia and second case is called azoospermia. Tubal infertility is present in female.
Q5. The technique of DNA fingerprinting was initially developed by
Answer : Option D
Explaination / Solution:
Sir Alec John Jeffreys, CH FRS (born 9 January 1950 in Oxford, Oxfordshire, England) is a British geneticist, who developed techniques for DNA fingerprinting and DNA profiling which are now used worldwide in forensic science to assist police detective work and to resolve paternity and immigration disputes.
He is a professor of genetics at the University of Leicester, and he became an honorary freeman of the City of Leicester on 26 November 1992.
In 1994, he was knighted for services to genetics
Q6. During which month of pregnancy first movement of fetus is observed
Answer : Option A
Explaination / Solution:
The movement of fetus is observed on fifth month of pregnancy. In first month heart is formed. In second months limbs and digits are formed. At the end of three months, all major organs and genital organs are formed.
Q7. Presence of different types of beaks in finches of Galapgos islands adapted to different feeding habits provides evidence of
Answer : Option D
Explaination / Solution:
Darwin published his intellectual bombshell, the “Origin of Species,” later in 1859. He speculated that birds, resembling starlings, came to the Galapagos Islands by wind. Evolution took over and different groups developed different diets. When, he wrote, “an immigrant first settled on one of the islands, it would undoubtedly be exposed to different conditions in the different islands (where) it would have to compete with a different set of organisms. Then, natural selection would probably favor different varieties in the different islands.”
Q8. Viability period of human ovum is _____.
Answer : Option B
Explaination / Solution:
Ovum is released from ovary in the middle of menstrual cycle. The ovum remains viable for 2 days. If insemination occurs in this period, there is a chance of pregnancy. After two days ovum disintegrate.
Q9. PCR and Restriction Fragment Length Polymorphism are the methods for
Answer : Option C
Explaination / Solution:
The main types of Genetic (DNA) fingerprinting methods in use at this time are:
- Restriction fragment length polymorphism (RFLP) analyzes the length of the strands of the DNA molecules with repeating base pair patterns. The drawback with this system is that it requires a considerable amount of DNA in order to be used.
- The polymerase chain reaction (PCR) was developed by Karry Mullis of the Cetus Corporation in 1983 for use in research laboratories for establishing hereditary authentication. The drawback was that it was not as discriminating as the RFLP.
- Amplified fragment length polymorphism (AmpFLP) came into vogue in the 90's and is still popular in the smaller countries involved in the process of DNA fingerprinting.
- The short tandem repeat (STR) methodology for extracting DNA is the system most widely used form of DNA fingerprinting.
Q10. The embryo at 16-celled stage is called
Answer : Option C
Explaination / Solution:
Zygote undergoes several mitotic divisions to form blastula, which is a spherical hollow structure. Further division in the cells leads to formation of 16-celled stage called as Morula.
