Model Paper 3 — BIOLOGY STD 12 Science — Question

Identify A, B, C, D, E and F in the table given below:

S. No.	Component-I	Component-II	Chemical linkage bonding the two components	Product
(i)	A	B	C	Nucleotide
(ii)	Nucleotide	D	E	Nucleotide
(iii)	Nucleotide	Nucleotide	F	Dinucleotide

Fertilisation is essential for production of seed, but in some angiosperms, seeds develop without fertilisation.

1. Give an example of an angiosperm that produces seeds without fertilisation Name the process.
2. Explain the two ways by which seeds develop without fertilisation.

Discuss: "Different levels of biodiversity".

Kanchan went to a garden and saw some flowers which were closed. She assumed that those flowers must be buds. But she was astonished to see that all the flowers of that plant were closed and none of them was open. She was confused and asked her queries to her teacher.

1. What do you think, are there any plants with closed flowers? Give an example.
2. Are such plants get pollinated? Explain.
3. What are such flowers/ plants called?
4. What values are shown by Kanchan?

What is an endangered species? Give an example of an endangered plant and animal species each?

How are the structural genes activated in the lac operon in E. coli?

Practise drawing various animals and plants.

Explain the process of emasculation and baggingof flowers. State their importance in breeding experiments.

How are the following used in biotechnology?

1. Plasmid DNA
2. Recognition sequence
3. Gel electrophoresis