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Can you recall meiosis and indicate at what stage a recombinant DNA is made? - Biology

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प्रश्न

Can you recall meiosis and indicate at what stage a recombinant DNA is made?

थोडक्यात उत्तर

उत्तर

In meiosis, the number of chromosomes is reduced to half. In the first meiotic division, one or more segments are exchanged between homologous chromosomes of each pair, i.e., they cross over.

Homologous chromosomes form pairs in the zygotene substage of the first prophase of meiotic division. This process is called synapsis. In the pachytene substage, round microscopic knobs appear at one or more places in the synaptonemal complex, these are called recombination nodules.

The mutual exchange of one or more segments between the interconnected chromatids of homologous chromosomes is called crossing over. This results in the formation of homologous recombinant DNA. Recombination nodes are formed at the sites where pieces of chromatids break and rejoin for transduction.

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Processes of Recombinant DNA Technology
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पाठ 11: Biotechnology : Principles and Processes - Exercises [पृष्ठ २०५]

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एनसीईआरटी Biology [English] Class 12
पाठ 11 Biotechnology : Principles and Processes
Exercises | Q 8 | पृष्ठ २०५

संबंधित प्रश्‍न

Besides better aeration and mixing properties, what other advantages do stirred tank bioreactors have over shake flasks?


Describe briefly the following:

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Describe briefly the following:

Downstream processing


In a pathological lab, a series of steps were undertaken for finding the gene of interest. Describe the steps, or make a flow chart showing the process of amplification of this gene of interest.


______ plays an important role in blood clotting.


DNA fragments generated by the restriction endonuclease in a chemical reaction can be separated by ______.


A single strand of nucleic acid tagged with a radioactive molecule is called ______.


Gene Amplification using primers can be done by ______.


PCR proceeds mthree distinct steps governed by temperature, they are in order of ______.


In PCR, primers are used for ______.


During the purification process for recombinant DNA technology, the addition of chilled ethanol precipitates out ______.


Rising of dough is due to ______.


Which of the following contributed in popularising the PCR (polymerase chain reactions) technique?


Significance of 'heat shock' method in bacterial transformation is to facilitate ______.


Identify and explain steps ‘A’, ‘B’ and ‘C’ in the PCR diagram given below.


Illustrate the design of a bioreactor. Highlight the difference between a flask in your laboratory and a bioreactor which allows cells to grow in a continuous culture system.


Read the paragraph given below and answer and questions that follow:

Enzyme Taq polymerase, is extracted from a eubacterial microorganism Thermus aquaticus from Yellowstone National Park in Montana, USA and isolated by Chien et al. (1976). Taq polymerase successfully replaced the DNA polymerase from E.coli that was being used in PCR earlier and this shift revolutionised the PCR technique.
  1. Taq polymerase after its discovery replaced E.coli DNA polymerase in PCR technique. Explain giving reasons why was the need felt for the change?
  2. What is a primer and its importance in PCR?
  3. Write the importance of PCR as a diagnostic tool.

Write the scientific name of the source organism of the thermostable DNA polymerase used in PCR.


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