Reproductive Health — BIOLOGY STD 12 Science — Question

During a biology lecture in class the teacher called apple seeds as seeds but maize seeds as grains. On hearing this Amit got confused and asks her teacher the reason behind this. The teacher appreciated Amit and cleared all his doubts.

1. What is the difference between seed and grain?
2. How are maize grains formed?
3. Explain along with a labelled diagram of the vertical section of a maize grain.
4. What values are shown by Amit?

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

Alien species invasion has been a threat to biodiversity. Justify with the help of a suitable example. List any other three causes responsible for such a loss.

Describe the initiation process of transcription in bacteria.

Given below is a list of six micro-organisms. State their usefulness to humans.

1. Nucleopolyhedrovirus.
2. Saccharomyces cerevisiae.
3. Monascus purpureus.
4. Trichoderma polysporum.
5. Penicillium notatum.
6. Propionibacterium sharmanii.

Write the functions of: Tapetum

The following table shows the genotypes for ABO blood grouping and their phenotypes. Fill in the gaps left in the table.

S. No.	Genotype	Blood group
i.	IA IA	A
ii.	_________________	A
iii.	IB IB	B
iv.	________________	B
v.	IA IB	_______________
vi.	_________________	O

There are certain complexities in eukaryotic transcription. Bring out the significance of such complexities.

How does pollen tube enter the ovule?

Egrets are often seen along with grazing cattle. How do you refer to this interaction? Give a reason for this association.