PUC Science 2nd PUC Class 12 - Karnataka Board PUC Question Bank Solutions for Biology

List the three stages the annuals and biennial angiosperms have to pass through during their life cycle.

By taking two examples explain how has bio-fortification helped in improving food quality.

In a flowering plant a microspore mother cell produces four male gametophytes, while a megaspore mother cell forms only one female gametophyte. Explain.

Read the statement and answer the questions that follow.

A flower of brinjal has 520 ovules in its ovary. However, it produces a fruit with only 480 viable seeds.

(a) What could have prevented the rest of the 40 ovules from maturing into viable seeds? Explain giving a reason.

(b) Describe the development of a dicot embryo in a viable seed.

(c) Why certain angiospermic seed albuminous while others are exalbuminous? Explain.

A capsicum flower has 240 ovules in its ovary. But, it produces a fruit with only 180 viable seeds.
 

Bottled fruit juices are clearer as compared to those made at home. Explain.

Our government has intentionally imposed strict conditions for M.T.P. in our country. Justify giving a reason.

How does a desert plant adapt to the dry, warmer environmental conditions ?

Name the kind of diseases/disorders that are likely to occur in humans if
    (i) mutation in the gene that codes for an enzyme phenyl alanine hydrolase occurs,
    (ii) there is an extra copy of chromosome 21,
    (iii) the karyotype is XXY.

Mention any one symptom of the diseases/disorders named above.

What role does an individual organism play as per Darwin's theory of natural selection?

Mention the evolutionary significance of the Shrews

Mention the evolutionary significance of the Lobefins

Mention the evolutionary significance of the Homo habilis

Mention the evolutionary significance of the Homo erectus

Explain divergent evolution with two examples. 

One of the major contributions of biotechnology is to develop pest-resistant varieties of cotton plants. Explain how it has been made possible.

Name and explain the technique used for separating DNA fragments and making them available for biotechnology experiments.

Describe the structure of a nucleosome.

What is an age-pyramid?