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Biochemistry Basics – 21472

Question

True about mitochondrial DNA-

A. UGA codes for tryptophan

B. Codes for 13 protein

C. Circular double stranded DNA

D. All

 

Show Answer

Correct Answer » D

Explanation

Major Features of Human Mitochondrial DNA
– It is circular double-stranded, composed of heavy and light strands.
– It encodes 13 protein subunits of the respiratory chain-

  • Seven sub-units of NADH dehydrogenase 
  • Cytochrome b of complex III
  • 3 subunits of cytochrome oxidase
  • 2 subunits of ATP synthase

– Encodes tRNA molecules and Ribosomal RNAs
– Genetic code is slightly different from the standard code-

  • UGA(stop codon) is read as Trp.
  • AGA and AGG (code for arginine) is read as the stop codon

– High mutation rate

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