Human Reproduction — BIOLOGY STD 12 Science — Question

Explain the following with reference to drug/alcohol abuse:

1. Addiction.
2. Dependence.
3. Withdrawal symptoms

Haemophilia is a sex linked recessive disorder of humans. The pedigree chart given below shows the inheritance of haemophilia in one family. Study the pattern of inheritance and answer the questions given.

1. Give all the possible genotype of the members 4, 5 and 6 in the pedigree chart.
2. A blood test shows that the individual 14 is a carrier of haemophilia. The member numbered 15 has recently married the member numbered 14. What is the probability that their first child will be a haemophilic male?

i. Compare the mechanism of sex determination in humans with that of honey bees, with respect to chromosome number.
ii. How is the gamete formation comparable in the above two cases?

Name the kind of organisms which constitute the pioneer community of xerarch and hydrarch successions respectively.

When someone buys packets of cigarettes, cannot miss the statutory warning that is present on the packing which warns against smoking and says how it is injurious to health. Yet, smoking is very prevalent in our society, both among young and old. Advise the adolescents about the importance of avoiding smoking. (Mention any six points.)

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?

Study the given pedigree chart and answer the questions that follow:

Is the trait sex–linked or autosomal?

What is a recombinant DNA vaccine? Give two examples.

Mention three uses of PCR.

What do you understand by connecting Link? Explain their importance in biological evolution by giving suitable examples.