Biodiversity and Conservation — BIOLOGY STD 12 Science — Question

Differentiate the following and give examples of each: Innate and acquired immunity

1. Identify the polarity at A and B respectively in the figure given below.
2. Explain the mechanism the figure represents.

A person shows strong unusual hypersensitive reactions when exposed to certain substances present in the air. Identify the condition. Name the cells responsible for such reactions. What precaution should be taken to avoid such reactions.

For a layman, both apple and banana are fruits. But a biology student categorises fruits as true fruits, false fruits and parthenocarpic fruits. Justify.

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

1. Is the trait recessive or dominant?
2. Is the trait sex-linked or autosomal?
3. Give the genotypes of the parents shown in generation I and of their third and fourth child in generation II.

What are ecological pyramids and how are they formed. Explain there different types

Mention the three attributes that a stable community has.

Classify the following as examples of homology and analogy:

(i)	Mouth parts of cockroach and butterfly
(ii)	Hearts of rabbits and human beings
(iii)	Eyes of octopus and mammals
(iv)	Sweet potato and potato
(v)	Stings of honey bee and scorpion
(vi)	Tendrils of Lathyrus and tendrils of Gloriosa

(i) EcoRI has played a very important role in recombinant DNA technology.
(a) Explain the naming convention of Eco RI.
(b) Write the name of the recognition site and cleavage site of this restriction enzyme.
(ii) What is the longitudinal extension of DNA produced by these restriction enzymes called? Describe their role in the formation of r-DNA.

Embryo sacs of some apomictic species appear normal but contain diploid cells. Suggest a suitable explanation for the condition.