Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

The image below eleborates enzyme-replacement therapy.

i. Explain enzyme-replacement therapy to treat adenosine deaminase deficiency.
ii. Mention two disadvantages of this procedure.

Name the two end products of double fertilization in angiosperms. How are they formed? Write their fate during the development of seed.

In the 1950s, there were hardly any mosquitoes in Delhi. The use of pesticide DDT on standing water killed their larvae. It is believed that now there are mosquitoes because they evolved DDT resistance through the interaction of mutation and Natural selection. Pointwise, state in a sequence how that could have happened.

The schematic representation given below shows the concept of Central Dogma.

A. During the process of replication and transcription the pairing of
nitrogenous bases is not similar. Explain.
B. How is the above process modified in a retrovirus? Name the process.
C. Justify why during the process of transcription only a segment of DNA is copied into RNA.

Define the terms and give one example for each: Parasitism

Explain - Nucleoside & Nucleotide

How does pollen tube enter the ovule?

Given below is the representation of amino acid composition of the relevant translated portion of b–chain of haemoglobin, related to the shape of human red blood cells.

Is this representation indicating a normal human or a sufferer from certain related genetic disease? Give reason in support of your answer.

Name any three enzymes used in industry and explain their importance.