Question

Fill in the blank: Transcription occurs by _____________ in a _______?

A. DNA replication; DNA loop
B. Base pairing; bubble of unpaired DNA
C. Reading DNA coding sequence; terminal loop
D. Splicing; spliceosome

Answer 1

Transcription occurs by base pairing within a bubble of unpaired DNA, facilitated by RNA polymerase to produce mRNA.

Step-by-step explanation:

Transcription occurs by base pairing in a bubble of unpaired DNA. During transcription, the enzyme RNA polymerase moves along the DNA template strand, reading nucleotides in a 3' to 5' direction, and assembles the mRNA strand in a 5' to 3' direction.

The nucleotides adhere to base pairing rules, where uracil (U) pairs with adenine (A) and cytosine (C) pairs with guanine (G), forming the mRNA transcript.

The region of DNA unwinding during transcription is known as the transcription bubble.

The mRNA sequence produced is complementary to the DNA template strand and almost identical to the nontemplate (coding) strand, except for the substitution of U nucleotides for T nucleotides.