List of top Biology Questions

Flowering plants with hermaphrodite flowers have developed many reproductive strategies to ensure cross-pollination. Study the given outbreeding devices adopted by certain flowering plants and answer the questions that follow.

Note : All plants belong to the same species. No pollen tube growth/inhibition of pollen germination on stigma. Pollen germination on stigma.

  • [(a)] Name and define the outbreeding device described in the above table.
  • [(b)] Explain what would have been the disadvantage to the plant in the absence of the given strategy.
Student to attempt either option (A) or (B):
(A) Why are restrictions imposed on MTP in India? Up to how many weeks or trimesters is MTP considered relatively safe for a female, if necessary to perform, by a medical practitioner?
OR
(B) Expand PID. Name any two common viral infections transmitted through sexual contact in human females.

Student to attempt either option (A) or (B):
(A) How is the interaction between Ophrys and its specific bee pollinator one of the best examples of co-evolution? Explain. 
OR 
(B) Arrange the given important steps of decomposition in their correct order of occurrence in the breakdown of complex organic matter and explain the fourth step in the process.

(A) Comment upon the mode of pollination in Vallisneria and Zostera. (B)
The technique for the early detection of a disease based on the principle of antigen-antibody interaction is:
Explain how the immunity of a person is affected if there is atrophy (degeneration) of the thymus gland at an early stage of life.
Why are restrictions imposed on MTP in India? Up to how many weeks or trimesters, is MTP considered relatively safe for a female, if necessary to perform, by a medical practitioner?
Student to attempt either option (A) or (B):
(A) Name the Indian crop variety for which, in 1997, an American company got patent rights through the US Patent and Trademark Office. This is considered a case of Biopiracy. Justify.
OR
(B) State two purposes for which the Indian Government has set up GEAC (Genetic Engineering Approval Committee).
Write the scientific name of the source organism of the thermostable DNA polymerase used in PCR.
Describe ‘Ex situ’ approach for conserving biodiversity. Give any two examples.
The RNA triplet UAG acts as a stop codon which terminates the synthesis of a polypeptide. Below is given a strand of DNA which codes for four amino acids.
In which position will an insertion of a thymine nucleotide result in the termination of translation?
DNA strand:
3′ T C C A C C C G A T G C 5′

Read the passage given below and answer the question. 
Food chains ‘P’ and ‘Q’ form an interconnection. ‘P’ initiates with wheat grass whose population supports a few grasshoppers, frogs and snakes. 
‘Q’ starts with dead decaying leaves of wheat grass which are eaten by earthworms and then food chain is continued with frog of food chain ‘P’. 
Identify the types of food chains ‘P’ and ‘Q’:

  • Why are transgenic animals so called?
  • With the help of an example each, explain the role of transgenic animals in the following:
    • [(i)] Vaccine safety
    • [(ii)] Biological products
A person is suffering from high grade fever. Which symptoms will help to identify if he/she is suffering from Typhoid, Pneumonia or Malaria?
Student to attempt either option (A) or (B): (A) What is meant by ‘right’ and ‘wrong’ type of pollen when pollen lands on the stigma? A two-celled right type pollen has landed on the stigma. Explain the events taking place till fertilization in angiosperms. Why is pollen pistil interaction said to be dynamic?
OR
(B)
  • Give the schematic representation of oogenesis in human females indicating chromosome number at each step.
  • In which part of the female reproductive system do the following events take place?
    • I. Formation of corpus luteum
    • II. Maturation of tertiary follicle
    • III. Fertilisation
    • IV. Implantation
(a) “The process of evolution of different species in a given geographical area starts from a point and literally radiates to other geographical areas.” Explain it with an example.
(b) Cite an example where more than one adaptive radiation has occurred in an isolated geographical area. Name the type of evolution your example depicts.
Student to attempt either option (A) or (B): (A) How is DNA isolated in purified form from a bacterial cell?
OR
(B) Explain how human functional insulin was produced by using recombinant DNA (rDNA) technology.
Assertion (A): A piece of DNA inserted into an alien organism generally does not replicate, if not inserted into a chromosome.
Reason (R): \textit{Chromosomes have specific sequences called ‘ori’ region, where DNA replication is initiated.
Gene therapy can be used to treat an ADA deficient patient. Explain.
Is it a permanent cure? How can ADA be cured permanently?
Assertion (A): Swiss cheese is characterized by large holes due to CO2 production.
Reason (R): It is ripened by growing a specific fungi.

Construct and label a transcription unit from which the RNA segment given below has been transcribed. Write the complete name of the enzyme that transcribed this RNA.

Student to attempt either option (A) or (B): (A) Ravi lives in a village where he suggested to the local farmers to introduce a fungus as biofertilizer into their crop fields. State the benefits provided by the fungus to the crop.
OR
(B)
  • [(i)] How do secondary lymphoid organs provide immunity?
  • [(ii)] Highlight the role of spleen as an organ that provides immunity.
Choose the option that correctly describes the gynoecium of \textit{Michelia:

In a certain population, the frequency of three genotypes is as follows:
Genotypes: PP Pp  pp 
Frequency: 22%  62%  16% 
Choose the option that shows the frequency of P and p alleles correctly:

Assertion (A): A male individual always inherits haemophilia from his mother.
Reason (R): The gene for haemophilia lies on X-chromosome.