CBSE 12TH BIOLOGY - Online Test
Q1. What is meant by RCH care?
Answer : Option B
Explaination / Solution:
RCH stands for reproductive and child health care. RCH deals with all problems related to healthy reproductive life, problems related to care during pregnancy and care of child after the birth with their immunization programme.
Q2. Choose the correct sequence:
Answer : Option A
Explaination / Solution:
A number of species living in a particular area makes the population. Different population of a ecosystem forms community and communities in a geographical area are called biome.
Q3. Antigen binding site in an antibody is found between
Answer : Option B
Explaination / Solution:
The antigen-binding (Fab) fragment is a region on an antibody that binds to antigens. It is composed of one constant and one variable domain of each of the heavy and the light chain.
Q4. A phenomenon where the third base of t-RNA at its 5’ end can pair with a non-complementary base of m-RNA is called
Answer : Option D
Explaination / Solution:
In 1966, Francis Crick proposed the Wobble Hypothesis. He postulated that the 5' base on the anticodon, which binds to the 3' base on the mRNA, was not as spatially confined as the other two bases, and could, thus, have non-standard base pairing.
Crick creatively named it for the small amount of play that occurs at this third codon position. Movement ("wobble") of the base in the 5' anticodon position is necessary for small conformational adjustments that affect the overall pairing geometry of anticodons of tRNA.
Q5. Which of the following pyramid/s is/are inverted:
Answer : Option D
Explaination / Solution:
In the aquatic system, the biomass can increase at higher trophic levels. For example, in Oceans, the food chain typically starts with phytoplankton and ends at predatory fish, which has largest biomass. Thus, the pyramid of biomass is inverted in the aquatic systems including marine, ponds etc.
Q6. Which of the following helps in absorption of phosphorus from soil by plants?
Answer : Option C
Explaination / Solution:
Anabaena is a photoautotrophic algae that generally grows in rice field. It increase the nitrogen in soil along with it also help in absorption of phosphorous from the soil by the plants.
Q7. Project elephant started in the year:
Answer : Option A
Explaination / Solution:
Project Elephant (PE) was launched by the Government of India in the year 1992 as a Centrally Sponsored Scheme with following objectives:
- To protect elephants, their habitat & corridors
- To address issues of man-animal conflict
- Welfare of captive elephants
Q8. What is the function of germ pore?
Answer : Option A
Explaination / Solution:
Pollen grain is covered by two layers. The outer layer is called exine, made up of tough material. The inner layer is intine. There is a small opening in exine layer through which pollen grain germinate to form pollen tube.
Q9. Failure of testes to descend into scrotum is called
Answer : Option A
Explaination / Solution:
Cryptochidism is an abnormal condition in male reproductive system in which scrotum does not descend outside the abdominal condition. The males may be not able to produce fertile sperm.
Q10. A human male produces sperms with the genotypes AB ,Ab , aB , ab pertaining to two diallelic characters in equal proportions. What is the corresponding genotype of this person?
Answer : Option A
Explaination / Solution:
The genotype AaBb of a male produce gametes AB,Ab, aB and ab in equal proportion as the law of segregation.
