The addition or deletion of one nitrogen base from a sequence of codons on mRNA has more serious effects than its substitution. Explain with an example.

Sometimes a change at the third nitrogen base of a codon has no effect on protein synthesis. Explain.

Questions based on diagram : Draw a figure describing the following : The reflecting surfaces of two mirrors make an angle of 90⁰ with each other . If a ray incident of one mirror has an angle of incidence of 30⁰ , draw the ray reflected from the second mirror . what will be its angle of reflection ?

Read the following paragraph and answer the questions based on it. Rhizobium produce nitrogenous compounds from atmospheric nitrogen. However, for this process of nitrogen fixation, they need leguminous plants like beans, sweet pea, soyabean, etc. as ‘host’. Rhizobium living in root nodules supply nitrates, nitrites and amino acids to that plant and in exchange get energy in the form of carbohydrates from it. Such a mutually beneficial relationship is called symbiosis. Beans and pulses are rich in proteins due to the nitrogenous compounds made available by Rhizobium. After harvesting a leguminous crop, the left-over roots and other plant parts are deliberately dumped in farm soil to maintain its bacterial population. The use of Rhizobium has helped to reduce the use of chemical fertilizers and thereby their adverse effects. It has also helped to reduce expenses on fertilizers and thus works to the benefit of farmers. Which plants act as a host to Rhizobium bacteria?

Read the following paragraph and answer the questions based on it. Rhizobium produce nitrogenous compounds from atmospheric nitrogen. However, for this process of nitrogen fixation, they need leguminous plants like beans, sweet pea, soyabean, etc. as ‘host’. Rhizobium living in root nodules supply nitrates, nitrites and amino acids to that plant and in exchange get energy in the form of carbohydrates from it. Such a mutually beneficial relationship is called symbiosis. Beans and pulses are rich in proteins due to the nitrogenous compounds made available by Rhizobium. After harvesting a leguminous crop, the left-over roots and other plant parts are deliberately dumped in farm soil to maintain its bacterial population. The use of Rhizobium has helped to reduce the use of chemical fertilizers and thereby their adverse effects. It has also helped to reduce expenses on fertilizers and thus works to the benefit of farmers. What is provided by the host plant to the Rhizobium bacteria?

Read the following paragraph and answer the questions based on it. Rhizobium produce nitrogenous compounds from atmospheric nitrogen. However, for this process of nitrogen fixation, they need leguminous plants like beans, sweet pea, soyabean, etc. as ‘host’. Rhizobium living in root nodules supply nitrates, nitrites and amino acids to that plant and in exchange get energy in the form of carbohydrates from it. Such a mutually beneficial relationship is called symbiosis. Beans and pulses are rich in proteins due to the nitrogenous compounds made available by Rhizobium. After harvesting a leguminous crop, the left-over roots and other plant parts are deliberately dumped in farm soil to maintain its bacterial population. The use of Rhizobium has helped to reduce the use of chemical fertilizers and thereby their adverse effects. It has also helped to reduce expenses on fertilizers and thus works to the benefit of farmers. How do the soil conditions improve by Rhizobium?

Read the following paragraph and answer the questions based on it. Rhizobium produce nitrogenous compounds from atmospheric nitrogen. However, for this process of nitrogen fixation, they need leguminous plants like beans, sweet pea, soyabean, etc. as ‘host’. Rhizobium living in root nodules supply nitrates, nitrites and amino acids to that plant and in exchange get energy in the form of carbohydrates from it. Such a mutually beneficial relationship is called symbiosis. Beans and pulses are rich in proteins due to the nitrogenous compounds made available by Rhizobium. After harvesting a leguminous crop, the left-over roots and other plant parts are deliberately dumped in farm soil to maintain its bacterial population. The use of Rhizobium has helped to reduce the use of chemical fertilizers and thereby their adverse effects. It has also helped to reduce expenses on fertilizers and thus works to the benefit of farmers. How does Rhizobium help to save money of the farmers?

Information about protein synthesis is stored in the DNA. Proteins are synthesized by DNA through RNA. This is also known as the central dogma of life. The nucleotide sequences of the mRNA produced are complementary to the DNA strand that is uded as the template for synthesis. This process of synthesis of RNA from DNA is known as transcription. The code for each amino acid consists of three nucleotides (triplet codon) that are present on the mRNA. The tRNA has an anticodon sequence complementary to the cofon on the mRNA. During translation, the code on mRNA is read nad respective amino acids brought by tRNA are joined together by peptide bonds. Based on the given paragraph, answer the followig question: i. If 3'-AACGT-5' is a sequence of the template DNA strand, what would be the nucleotide sequence of the corresponding mRNA synthesized from it? ii. What is the difference in nitrogeneous bases of DNA and RNA? iii. Which enzyme woud be required for the synthesis of RNA from DNA during transcription? iv. How many amino acids can the following mRNA sequence code for ? 5'-UUCAGCCGUGUCAUU-3' v. What is the function of mRNA in translation?

Read the following paragraph and answer the questions based on it. Rhizobium living in root nodules supply nitrates, nitrites and amino acids to that plant and in exchange get energy in the form of carbohydrates from it. Such a mutually beneficial relationship is called symbiosis. Rhizobium produce nitrogenous compounds from atmospheric nitrogen. However, for this process of nitrogen fixation, they need leguminous plants like beans, sweet pea, soyabean, etc. as ‘host’. Beans and pulses are rich in proteins due to the nitrogenous compounds made available by Rhizobium. After harvesting a leguminous crop, the left-over roots and other plant parts are deliberately dumped in farm soil to maintain its bacterial population. The use of Rhizobium has helped to reduce the use of chemical fertilizers and thereby their adverse effects. It has also helped to reduce expenses on fertilizers and thus works to the benefit of farmers. Why does left over roots and other plant parts are deliberately dumped in farm soil after harvesting a leguminous crop?

Question based on paragraph A class of students was taken on an excursion by the school to the banks of a river. They were explained that energy can be transferred from phytoplanktons to humans. This pattem of energy in the ecosystem could be explained as a ‘pyramid of energy’. The pyramid of energy consists of phytoplanktons at the bottom, followed by three successive trophic levels consisting of zooplanktons, fishes and humans respectively. There is a gradual crease of energy and number of organisms from the base to the apex of the pyramid. The passage of energy is referred to as ‘one way’ transport. Based on the above passage, answer the question If the aquatic ecosystem has 10,000 kcal concentrated by phytoplanktons, how much energy will be transferred to humans?

Question based on paragraph Students were taken to observe the crop cultivation in a potato farm in Maharashtra. The students observed that the yield of crops in Mr. Shyam's potato farm was more than that in his neighbour Bharat’s potato farm. Mr. Shyam was using a different variety of the crop, which he suggests has been disease-free ever since he planted the seeds. Based on the above passage, answer the given question Are there any adverse effects of using such crops? Mention one.