Reproductive Health — BIOLOGY STD 12 Science — Question

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.

In the following table of interspecific interactions, fill the blanks with (+) sign for beneficient interaction, (-) sign for detrimental and 0 for neutral interaction.

Species A	Species B	Name of Interaction
+		Mutualism
	-	Competition
	-	Predation
+		Parasitism
+		Commensalism
	0	Amensalism

A couple where both husband and wife are producing functional gametes, but the wife is still unable to conceive, is seeking medical aid. Describe any one method that you can suggest to this couple to become happy parents.

Write the full form of PCR. What are the three basic steps involved in a single PCR amplification cycle?

Make a list of any three outbreeding devices that flowering plants have developed and explain how they help to encourage cross-pollination.

Differentiate between intraspecific and inter specific competition.

During a school trip to ‘Rohtang Pass’, one of your classmate suddenly developed ‘altitude sickness’. But, she recovered after some time.

1. Mention one symptom to diagnose the sickness.
2. What caused the sickness?
3. How could she recover by herself after some time?

Explain the mechanism of reflex action with the help of a suitable diagram.

What is fertilisation? Where does it take place in the following:

1. Flowering plants.
2. Frogs.

Haemophilia and sickle-cell anaemia are blood related Mendelian disorders. Yet, they differ in their pattern of inheritance. Explain the difference.