Human Health and Disease — BIOLOGY STD 12 Science — Question

Name the stages when oogenesis and spermatogenesis initiate in human female and male, respectively.

In a monohybrid cross of plants with red and white flowered plants, Mendel got only red flowered plants. On self-pollinating these F₁ plants got both red and white flowered plants in 3 : 1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of parental generation.

List any four symptoms shown by Klinefelter’s syndrome sufferer. Explain the cause of this disease.

How HIV multiplies in the host body?

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.

What difference would be noticed in the phenotype of the normal and the sufferer related to this gene?

During a fire in an auditorium, a large number of assembled guests got burnt beyond recognition. Suggest and describe a modern technique that can help hand over the dead to their relatives.

A population is exhibiting genetic equilibrium answer the following with regard to this statement.

1. Explain the above statement.
2. Name the underlying principle.
3. Name any two factors which could upset the genetic equilibrium (i.e. allele frequency) of the population.

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

Following the collision of two trains a large number of passengers are killed. A majority of them are beyond recognition. Authorities want to hand over the dead to their relatives. Name a modern scientific method and write the procedure that would help in the identification of kinship.

With the help of labelled diagram replication- al of retrovirus.