Organisms and Populations — BIOLOGY STD 12 Science — Question

Explain the difference between the following :
(i) Nucleoside and nucleotide
(ii) DNA and RNA
(iii) Codon and anticodon
(iv) Transcription and translation
(v) Inductive regulation and inhibitory regulation
(vi) RNA splicing and RNA editing

Draw a picture of viral replication. Write the full name of AIDS pathogen. How does hybridization occur? Explain the symptoms of AIDS in human body.

DNA separated from one cell, when introduced in another cell, is able to bestow some of the properties of the former to the latter. What is this change called in technical terms? Describe the experiment evidences which led to the discovery of the above phenomenon.

Describe the mechanism of pattern of inheritance of ABO blood groups in humans.

Thalassemia and haemophilia are both Mendelian disorders related to blood. Write the symptoms of the diseases. Explain with the help of crosses the difference in the inheritance pattern of the two diseases.

OR

Why are thalassemia and hemophilia categorised as Mendelian disorders? Write the symptoms of these diseases. Explain their pattern of inheritance in humans. Write the genotypes of the normal parents producing a haemophilic son.

(i) Explain the significance of each of the following features present in plants given below:, (a) In rose-bay plant the stamens ripen before the stigma., (b) In certain species of primrose, the flowers have short stamen and long style., (c) The bisexual flower of mustard exhibits rejection of self-pollen grain., (ii) Explain how autogamy is prevented in castor and papaya plant respectively.

About 8% of human male population suffers from colourblindness whereas only about 0.4% of human female population suffers from this disease. Write an explanation to show how it is possible.

Discuss in detail the contributions of Morgan and Sturvant in the area of genetics.

Taking examples under each category, discuss upstream and downstream processing.