PUC Science 2nd PUC Class 12 - Karnataka Board PUC Important Questions for Biology

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.
 

Arrange the following hormones in sequence of their secretion in a pregnant woman. Mention their source and the function they perform:

hcG, LH, FSH, Relaxin

Where in the fallopian tube does fertilization occur in humans?

Describe the development of a fertilized ovum upto implantation.

Explain the ovarian and uterine events that occur during a menstrual cycle in a human female under the influence of pituitary and ovarian hormones respectively.

Differentiate between vas deferens and vasa efferentia.

Differentiate between spermatogenesis and spermiogenesis.

Choose the correct answer from the four options given below : 
 On which day of the menstrual cycle does ovulation take place ?

1. What precaution(s) would you recommend to a patient requiring repeated blood transfusion?
2. If the advise is not followed by the patient, there is an apprehension that the patient might contract a disease that would destroy the immune system of his/her body. Explain with the help of schematic diagram only how the immune system would get affected and destroyed.

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.

Why did T. H. Morgan select Drosophila melanogaster to study sex linked genes for his lab experiments ?

Choose the correct answer from the four options given below : 
In a human male, a sperm will contain : 

How does a degenerate code differ from an unambiguous one?

Write the function of RNA polymerase II.

Explain the process of transcription in Eukaryotes.

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

Explain divergent evolution with two examples.