Science (English Medium) Class 12 - CBSE Question Bank Solutions

______ occurs in RNA instead of the nitrogenous base thymine found in DNA.

Which ratio is constant for DNA?

Which of the following is a structural subunit of DNA?

Assertion: When the two genes in a dihybrid cross are situated on the same chromosome, the proportion of parental gene combinations is much higher than the nonparental type.

Reason: Higher parental gene combinations can be attributed to crossing over between two genes.

Given below is a dihybrid cross performed on Drosophila.

Which of the following conclusions can be drawn on the basis of this cross? When yellow bodied (y), white-eyed (w) Drosophila females were hybridized with brown bodied (y+), red-eyed males (w+) and F1 progenies were intercrossed, F2 generation would have shown the following ratio:

The main reason for the presence of both a leading and a lagging strand during DNA replication is, ______ 

Which of the following is not an invasive alien species in the Indian context?

Where among the following will you find pitcher plant?

The one - homed rhinoceros is specific to which of the following sanctuary?

Which one of the following is an endangered plant species of India?

Retroviruses do not follow central Dogma. Comment.

During in vitro synthesis of DNA, a researcher used 2’, 3’ – dideoxy cytidine triphosphate as raw nucleotide in place of 2’-deoxy cytidine. What would be the consequence?

The vitamin whose content increases following the conversion of milk into curd by lactic acid bacteria is ______.

Big holes in Swiss cheese are made by ______.

Why does ‘Swiss cheese’ have big holes?

What is the source organism for ECORI, restriction endonuclease?

Which species of Penicillium produces Roquefort cheese?

Name a microbe used for the production of Swiss cheese.

Which type of food would have lactic acid bacteria? Discuss their useful application.

The transfer of genetic material from one bacterium to another through the mediation of a viral vector is termed as ______.