Human Health and Disease — BIOLOGY STD 12 Science — Question

What is the association between the bumblebee and its favourite orchid Ophrys? How would extinction or change of one affect the other?

Name the major enzymes involved in DNA replication.

A person is born with a hereditary disease with a weakened immune system due to deficiency of an enzyme. Suggest a technique for complete cure for this disease, identify the deficient enzyme and explain the technique used for cure.

AtRNA is charged with the amino acid methionine.

1. Name the process involved in attachment.
2. Point out the mRNA codon and anticodon on tRNA for this amino acid.
3. Name the enzyme responsible for this attachment.

Differentiate between geitonogamy and xenogamy in plants. Which one between the two will lead to inbreeding depression and why?

Explain the difference between commensalism and mutualism types of interactions, with the help of a suitable example of each.

During an excursion to a botanical garden, the teacher shows an old tree, which was on the verge of extinction. As soon as the teacher advanced with the students, some enthusiastic students climbed up the tree and started cutting the branches, collecting its leaves as precious collection. Rajesh instead took photographs of the tree from various angles. The boys mocked at Rajesh while the teacher appreciated him.

1. How can biodiversity be conserved?
2. What international initiatives were taken to conserve biodiversity?
3. What values did Rajesh possess?

Give reason:

1. Population of different species are not capable of breeding with each other.
2. Intraspecific competition is more intense than interspecific competition.
3. Parasites tend to loose certain organs.

In a sea shore, the benthic animals live in sandy, muddy and rocky substrata and accordingly developed the following adaptations.

1. Burrowing.
2. Building cubes.
3. Holdfasts/ peduncle.

Find the suitable substratum against each adaptation.