List of top Biology Questions asked in CBSE CLASS XII

Explain the charging of an adaptor molecule. Why does this molecule need to be charged?

Write the initiating codon for translation, its anticodon, and the amino acid it codes for.

Identify the polarity from ‘X’ to ‘X$^\prime$’ in the mRNA segment shown. Mention how many more amino acids can be added to the polypeptide that is being translated and why.

Which one of the two curves is relevant in present days with respect to human population in our country and why?

Which one of the two curves is more “realistic” and why?

Mention what does the dotted line in the graph indicate and state its importance also.

Name and explain the process the RNA molecule transcribed from 8000 nucleotides long DNA undergoes to be able to translate a polypeptide of 400 amino acids.

Name this RNA product transcribed from the DNA that subsequently translates into a polypeptide of 400 amino acids. Mention the enzyme responsible for transcribing this type of RNA from the DNA.

Draw a well-labeled diagram of sectional view of male gametophyte/microspore of an angiosperm and write the functions of any two parts labelled. (Any four labels).

Write the number of RNA polymerases involved in the transcription of DNA in a prokaryote and eukaryotes.

A pea plant with purple flowers, when crossed with a plant with white, produced 50 plants with only purple flowers. On selfing these plants produced 482 plants with purple flower and 162 with white flowers. Explain the pattern of inheritance with the help of Punnett square.

Identify the growth curves ‘A’ and ‘B’.

Mention the difference in the site of transcription in a prokaryote and eukaryote cell.

Whose skulls ‘A’, ‘B’, and ‘C’ are shown below? Which of the two are more similar to each other?
\begin{figure}[h!] \centering \includegraphics[width=0.8\textwidth]{Screenshot 2025-01-16 122426.png} \caption{Skull} \end{figure}

Name the (i) ape-like (ii) man-like primates that existed 1.5 million years ago.

Anaerobic sludge digester

Name the human body organ affected by the consumption of these drugs.

How are such drugs consumed?

Name the group of drugs whose skeletal molecule is shown below:
\begin{figure}[h!] \centering \includegraphics[width=0.8\textwidth]{Screenshot 2025-01-16 122650.png} \caption{Drug} \end{figure}

Biodiversity hotspots cover less than 2\% of Earth’s land area. Strict protection of these areas can reduce the rate of ongoing extinctions. Explain.

Flocs

Differentiate between grazing food chain and detritus food chain.

Why is an early detection of these diseases essential?

Explain brood parasitism with the help of a suitable example.

How has the use of \textit{Agrobacterium as vector helped in controlling \textit{Meloidogyne incognita} infestation in tobacco plants? Explain in correct sequence.}