Science (English Medium) Class 12 - CBSE Important Questions

Describe the role of primers.

Describe the role of bacterium Thermus aquaticus in carrying the process of polymerase chain reaction.

A patient admitted in ICU was diagnosed to have suffered from myocardial infarction. The condition of coronary artery is depicted in the image below.

Name two bioactive agents and their mode of action that can improve this condition.

C-peptide of human insulin is ______.

Explain how recombinant human insulin was prepared in 1983 by Eli Lily an American company.

Eli Lilly's contribution for diabetic patients through r-DNA technology has been overwhelmingly accepted. Explain how?

• Assertion: PCR is a powerful technique to identify genetic disorders.
• Reason: PCR can detect mutations in low amounts of DNA.

The graph given below indicates the administration of the first (L) and second dose (M) of a vaccine. The corresponding response of the body is indicated by X, and Y. Interpret the graph and explain the reason for such a response shown by the body.

Explain mutualism with the help of any two examples.

Write what do phytophagous insects feed on.

Why do clown fish and sea anemone pair up? What is this relationship called?

How do mycorrhizae help the plants to grow better?  

How is mutualism different from commensalism?

Name the two intermediate hosts which the human liver fluke depends on to complete its life cycle so as to facilitate parasitization of its primary host.

Answer the following question.
Mention the term used to describe a population interaction between an orchid growing on a forest tree.

Answer the following question.
Mention the term used to describe a population interaction between an orchid growing on a forest tree.

Name and explain the interaction that is seen between clownfish and sea anemones.

Substantiate by giving two reasons as to why a holistic understanding of the flora and fauna the cropland is required before introducing an appropriate biocontrol method.

With the decline in the population of fig species it was noticed that the population of wasp species also started to decline. What is the relationship between the two and what could be the possible reason for decline of wasps?

What is mycorrhiza?