42. Which of the following is made from DNA? tRNA only mRNA only rRNA only mRNA

Question

42. Which of the following is made from DNA?

tRNA only

mRNA only

rRNA only

mRNA and tRNA only

mRNA, tRNA, and rRNA

43. Why is only one strand of DNA transcribed into mRNA?

Because transcribing both DNA strands would produce different amino acid sequences

Because mRNA is only required in small quantities

Because the other strand is transcribed directly into amino acids

Because all genes are located on the same DNA strand, while the other strand acts as protection

Because the other strand would produce the same amino acid sequence in reverse order

44. tRNA molecules are able to act as adapters between amino acids and mRNA during translation because:

tRNA binds to ribosomes.

tRNA can bind to both mRNA and an amino acid.

tRNA anticodons bind to amino acids.

tRNA is recognized by RNA polymerase.

tRNA molecules bind to promoter sequences to initiate transcription.

45. One of the pyrimidine bases in a DNA molecule is adenine.
__________________

True

False

tRNA only

mRNA only

rRNA only

mRNA and tRNA only

mRNA, tRNA, and rRNA

Explanation / Answer

42) RNA polymerase is involved in the synthesis of RNA from DNA. The process is known as transcription. Initiation of transcription begins with the binding of the RNA polymerase to a promoter sequence in the DNA. The enzyme helicase unwinds the double helical structure of the DNA molecule. RNA polymerase then progresses along the template strand in the 3’ to 5’ direction synthesizing a complementary RNA molecule with elongation occurring in the 5’ to 3’ direction.  tRNAs are transcribed by RNA polymerase III. Molecules of rRNA are synthesized inside nucleolus from DNA that contain genes that encode for rRNA. So, the answer for this question is option (e) mRNA, tRNA and rRNA.

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