List of top Biology Questions

Name the type of food chains responsible for the flow of larger fraction of energy in an aquatic ecosystem and a terrestrial ecosystem, respectively. Mention any two differences between the two food chains.
A segment of DNA, ‘TTG AGG GGG ATG’ was translated into an oligopeptide with the amino acids, Lysine - Serine - Proline - Tyrosine.
  • [(a)] Write the codons in correct sequence for the four amino acids.
  • [(b)] If first adenine in DNA is substituted by guanine, what will be the sequence of amino acids in the new oligopeptide?
  • [(c)] Write the anticodons for these amino acids.
(a) Mention any two advantages of micropropagation techniques.
(b) Write in brief how the process is carried out in the laboratory.
(c) Name any two important food plants grown commercially by this method.
A person is suffering from high grade fever. Which symptoms will help to identify if he/she is suffering from Typhoid, Pneumonia or Malaria?
A village health worker was taking a session with women. She tells them that one has to be careful while using oral pills as a method of birth control. Wrong usage can actually promote conception.
(A) Analyse the statement — oral pills need careful usage, as wrong usage can promote conception. Compare merits and demerits of using oral pills and surgical methods of birth control.
(B) Village women are confused as to how a thin metallic copper loop can prevent pregnancy. Explain the mode of action of IUDs. Give two points.
(a) Why are transgenic animals so called?
(b) With the help of an example each, explain the role of transgenic animals in the following:
  • [(i)] Vaccine safety
  • [(ii)] Biological products
Student to attempt either option (A) or (B):
(A) “A fully developed foetus initiates its delivery from the mother’s womb.” Explain.
OR
(B) Give reasons for the following:
  • Why can a woman generally not conceive a child after 50 years of age?
  • Polar bodies are formed during oogenesis and not during spermatogenesis.
Assertion (A): Replication of DNA takes place in S phase of the cell cycle.
Reason (R): DNA replication and cell division cycle should be highly coordinated.
Student to attempt either option (A) or (B):
(A) How does a human body respond when vaccine is introduced into it? It is said that vaccinations are a must for a healthy society. Justify.
OR
(B) Humans have innate immunity for protection against pathogens that may enter the gut along with food. What are the two barriers in our body that protect it from such pathogens?
Assertion (A): A piece of DNA inserted into an alien organism generally does not replicate, if not inserted into a chromosome.
Reason (R): Chromosomes have specific sequences called ‘ori’ region, where DNA replication is initiated.
Assertion (A): A male individual always inherits haemophilia from his mother.
Reason (R): The gene for haemophilia lies on X-chromosome.
A few stages and their respective time period in the evolutionary history of human beings are mentioned in the flowchart given below:
  • 15 mya — Primates walking like gorillas and chimpanzees existed.
  • 3–4 mya — Man-like primates walked in Eastern Africa. Fossils of their bones were discovered.
  • 2 mya — This ancestor lived in the East African grasslands and ate fruits.
  • 1.5 mya — This hominid had a brain size of 900 cc and probably ate meat.
Based on the above information, answer the following questions:
  • [(a)] Name one primate about 15 mya.
  • [(b)] Name one place where fossils of primates were discovered in Eastern Africa.
  • [(c)] Name the ancestor that lived in the East African grasslands about 2 mya.
  • [(d)] Name the hominid that was found around 1.5 mya.
Out of the following, select the correct match:
Assertion (A): Swiss cheese is characterized by large holes due to CO2 production.
Reason (R): It is ripened by growing a specific fungi.
A biologist studied the population of rats in a granary. He found the average natality was 280, average mortality was 200, immigration was 40 and emigration was 50. The net increase in population is:
India has only 2.4% of the world's land area but its share of the global species diversity is:
Which one of the following is not the product of transgenic experiments?
Choose the option that correctly describes the gynoecium of Michelia:

The given graph shows the range of variation among population members, for a trait determined by multiple genes. If this population is subjected to disruptive selection for several generations, which of the following distributions is most likely to result?

Which of the following conditions correctly describes the manner of determining the sex in the given options?
Given below are the events that are observed in an artificial hybridisation programme. Arrange them in the correct sequential order and select the correct option.
  • Re-bagging
  • Selection of parents
  • Bagging
  • Dusting the pollens on stigma
  • Emasculation
  • Collection of pollens from male parent
Which one of the following immune system components does not correctly match with its respective role?
What are minisatellites?
Identify the incorrect statement regarding PCR.
The following information is about drugs and tobacco. Select the correct statement from the options given below.