CBSE Students who are preparing for upcoming 12th biology exam must practice this class 12 biology solved PYQ 2025. This will be very helpful for students in their exam preparation. Students can understand the exam pattern, question difficulty and also can do self analysis with the help of this PYQ.
We have also given solutions of each question so that student can cross check their answer. Practising Class 12 Biology Previous Year Question papers 2025 before exam can boost confidence in students and students can score better marks in exam. Different set of PYQ has given in this post and CBSE experts have prepared solutions of this PYQ.
Class 12 Biology PYQ 2025 SET 1 Question
Class 12 Biology PYQ 2025 SET 1 Solutions
Class 12 Biology PYQ 2025 SET 2
Class 12 Biology PYQ 2025 SET 2 Solutions
Class 12 Biology PYQ 2025 SET 1
Class 12 Biology PYQ 2025 SET 1 Solutions
Class 12 Biology PYQ 2025 SET 2
Class 12 Biology PYQ 2025 SET 2 Solutions
Also Check:
Class 12 Biology PYQ 2019
Class 12 Biology PYQ 2026
CBSE exam is usually held between feb and April every year. And for many students, this exam decides their career specially who want to pursue a career in biology or biotechnology. Practising only chapter is not enough for scoring good marks in exam. Solving Class 12 Biology PYQs is also important.
We hope students found this class 12 biology solved PYQ 2025 helpful for them. Keep learning if you have any questions you can ask in comment section. Also you can also help your friend by sharing this post to them.
Important Question of Class 12 Biology PYQ 2025
Question
Student to attempt either option-(A) or (B) :
(A) A patient with ADA deficiency requires periodic infusion of genetically engineered lymphocytes. Explain why such periodic infusion is required and also suggest a permanent cure for such ADA deficiency.
OR
(B) Describe in brief any two techniques that can be utilised to transfer recombinant DNA into the host cell directly without using any vector.
Solution
(A) The genetically engineered lymphocytes are not immortal hence the patient requires periodic infusion
There could be permanent cure if the gene isolated from bone marrow cells producing ADA is introduced into cells (lymphocytes) at early embryonic stages
OR
(B) Micro-injection, Recombinant DNA is directly injected into the nucleus of an animal.
Biolistics or gene gun, plants cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA/
Heat shock, Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice which is followed by placing them briefly at 42° C (heat shock) and then putting them back on ice.
Question :
(A) A patient with ADA deficiency requires periodic infusion of genetically engineered lymphocytes. Explain why such periodic infusion is required and also suggest a permanent cure for such ADA deficiency.
OR
(B) Describe in brief any two techniques that can be utilised to transfer recombinant DNA into the host cell directly without using any vector.
Solution
(A)
The genetically engineered lymphocytes are not immortal hence the patient requires periodic infusion.
There could be permanent cure if the gene isolated from bone marrow cells producing ADA is introduced into (lymphocytes) cells at early embryonic stages.
OR
(B)
Micro-injection: Recombinant DNA is directly injected into the nucleus of an animal.
Biolistics or gene gun: Plant cells are bombarded with high velocity micro-particles of gold or tungsten coated with DNA.
Heat shock: Recombinant DNA can then be forced into such cells by incubating the cells with recombinant DNA on ice which is followed by placing them briefly at 42°C (heat shock) and then putting them back on ice.