12 Class Fsc Part 2 Short Questions Online Preparation of biology chapter 20 (Chromosoms and DNA)

Online Short Questions For Chapter 6 "12th Class Biology Chapter 20 Short Questions Preparation "

Try The Short Questions For 12th Class Biology Chapter 20 Short Questions Preparation

  • Total Questions10

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Biology - 12th Class Biology Chapter 20 Short Questions Preparation

Question # 1

What are mutagens? Give one example.

  • Ans 1: In genetics,a mutagen is a physical or chemical agent that changes the genetic material,usually DNA of an organism and thus increases the frequency of mutations.
    For Example: X-ray,ultraviolet radiations etc.
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Prepare Complete Set Wise Questions For Chapter 6 "12th Class Biology Chapter 20 Short Questions Preparation "

12th Class Biology Chapter 20 Short Questions Preparation - Set 1

Question # 1

What are mutagens? Give one example.

  • Ans 1: In genetics,a mutagen is a physical or chemical agent that changes the genetic material,usually DNA of an organism and thus increases the frequency of mutations.
    For Example: X-ray,ultraviolet radiations etc.
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12th Class Biology Chapter 20 Short Questions Preparation - Set 2

Question # 1

Give the chemical composition of RNA.

  • Ans 1: RNA is composed of nitrogen bases (adenine.guanine,cytosine and uracil),pentose sugar(ribose) and phosphate group.
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12th Class Biology Chapter 20 Short Questions Preparation - Set 3

Question # 1

Differentiate between pyrimidines and purines.

  • Ans 1: Pyrimidines: Pyrimidines are nitrogenous bases present in nucleic acids,having only single ringed structure which is only six cornered.
    Examples: Cytosine,Thymine and uracil.
  • Ans 2: Purines: Purines are another type of nitrogenous bases present in nuclei acids having double ringed structure. One ring issoc cornered while second is of five cornered.
    Example: Adenine & Guanine.
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12th Class Biology Chapter 20 Short Questions Preparation - Set 4

Question # 1

Give the functions of the DNA polymerase III.

  • Ans 1: DNA polymerase III progressively threads the DNA through the enzyme complex,moving at rapid rate,some 1000 nucleotides/second.
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12th Class Biology Chapter 20 Short Questions Preparation - Set 5

Question # 1

How is newly synthesized mRNA protected after transcription?

  • Ans 1: A cap and tail is added so that molecule may remain stable during its travelling to cytoplasm. The cap is in the form of 7-methyl GTP where as tail is in the form of poly A tail linked to 3 end of the RNA.These cap and tail protects RNA from action of enzymes.
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12th Class Biology Chapter 20 Short Questions Preparation - Set 6

Question # 1

Define phenylketonuria. OR What is phenylketonuria?

  • Ans 1: In phenylketonuria,phenylalanine is not degraded because of defective enzyme phenylalanine hydroxylase. Phenylalanine consequently accumulates in the cells leading to mental retardation,as the brain cells fails to develop in infancy.This disorder is due to point mutation.
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20th Chapter

12th Class Biology Chapter 20 Short Questions

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