Q7 of 53 Page 32

“Genes contain the information that is required to express a particular trait.” Explain.

Based on the observations of monohybrid cross between a tall (TT) and dwarf (tt) plant; Mendel proposed that something was stably passed down unchanged from parent to offspring through the gametes over successive generations. He called these things as factors. Now we call them as genes. So genes are the unit of inheritance. They contain the information that is required to express a particular trait. Genes which code for a pair of contrasting traits are known as alleles.

The genes present in an organism show a particular trait by way of forming certain product. This is facilitated by the process of transcription and translation (according to central dogma of genetics).



More from this chapter

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5

The pedigree chart given below shows a particular trait which is absent in parents but present in the next generation irrespective of sexes. Draw your conclusion on the basis of the pedigree.


 6

In order to obtain the F1 generation Mendel pollinated a pure-breeding tall plant with a pure breeding dwarf plant. But for getting the F2 generation, he simply self-pollinated the tall F1 plants. Why?

 8

How are alleles of particular gene differ from each other? Explain its significance.

 9

In a monohybrid cross of plants with red and white flowered plants, Mendel got only red flowered plants. On self-pollinating these F1 plants got both red and white flowered plants in 3:1 ratio. Explain the basis of using RR and rr symbols to represent the genotype of plants of parental generation.