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100 questions in this collection · Page 3 of 10
Sexual Reproduction In Flowering Plants
Sexual Reproduction In Flowering Plants
Principles Of Inheritance And Variation
AI-generated explanation. Check against your textbook.
Pleiotropism means one gene affecting many phenotypic traits. So option 4 is correct. A single gene influences multiple features such as color, height, and metabolism in some organisms as described in NCERT discussions of gene action.
In pleiotropy, a single mutant gene can cause multiple symptoms or disorders, illustrating how genes can have widespread effects beyond one trait.
A single gene may influence more than one character (pleiotropy).
Principles Of Inheritance And Variation
AI-generated explanation. Check against your textbook.
The first use of recombination frequency to map gene positions on a chromosome was by Alfred Sturtevant. He proposed that the frequency of crossing over between two genes reflects their distance apart on the chromosome, enabling gene mapping. This idea came from Thomas Hunt Morgan's discovery of linkage and crossing over, but it was Sturtevant who used recombination data to create the first gene map.
Sturtevant’s work laid the foundation for genetic mapping, showing that genes are arranged linearly on chromosomes and that recombination frequency correlates with distance.
Recombination frequency between two genes is a measure of the distance between them on a chromosome (gene mapping).
Molecular Basis Of Inheritance
AI-generated explanation. Check against your textbook.
In eukaryotes, RNA polymerase III transcribes small RNA molecules: tRNA genes, 5S rRNA, and many snRNA genes. This matches option 3. RNA polymerase I transcribes most rRNAs (28S, 18S, 5.8S), and RNA polymerase II transcribes precursors of mRNA and most snRNA and microRNA genes, not the ones listed for Pol III.
Pol III products include structural RNAs essential for protein synthesis and RNA processing, such as tRNA and 5S rRNA.
RNA polymerase III transcribes tRNA, 5S rRNA and snRNA (small RNAs).
Molecular Basis Of Inheritance
Molecular Basis Of Inheritance
Biotechnology Principles And Processes
Biotechnology Principles And Processes
AI-generated explanation. Check against your textbook.
In gene gun or biolistic method, microscopic metal particles are coated with DNA and propelled into plant cells. NCERT mentions that these microparticles are usually made of tungsten or gold because they are dense and can deliver DNA efficiently without causing excessive damage. This allows genetic material to reach the cell interior and integrate. Among the options, only tungsten or gold (choice 4) are used; silver, copper, or zinc are not used for this purpose in standard NCERT descriptions.
The gene gun is also called biolistic delivery and was developed to transform plant cells that are hard to infect with other methods.
Microparticles of tungsten or gold are used in the gene gun method to deliver DNA into plant cells.
Biotechnology Principles And Processes
AI-generated explanation. Check against your textbook.
During recombinant DNA purification, chilled ethanol is added to the sample to precipitate nucleic acids. Ethanol causes DNA to come out of solution as a solid because it reduces its solubility in water. This helps in collecting DNA by spooling it out. Hence, the correct option is DNA.
DNA precipitates as a visible, sticky mass when ethanol is added and the mixture is kept cold, aiding its collection by centrifugation.
“Ethanol precipitation is used to precipitate DNA during purification.”