Which of the two dna strands serves as the template for transcription?
a. either dna strand may be used as a template by rna polymerase, but a single dna strand oriented in the 3'–5' direction is used as a template each time transcription occurs.
b. the dna strand oriented in the 5'–3' direction is the only template because only this strand contains the polymerase binding sequences necessary to initiate transcription.
c. the dna strand oriented in the 5'–3' direction is the only template because rna polymerase synthesizes only in the 5'–3' direction.
d. both dna strands serve as templates simultaneously for rna polymerase, with continuous transcription on the leading strand and discontinuous transcription on the lagging strand.

The correct answer will be option-A

Explanation:

The process of transcription form a transcript molecule called mRNA from a single strand of DNA called template strand or antisense strand.

The process of transcription is mediated by the RNA polymerase enzyme which adds the nucleotide base pairs in (A, U, G, or C) to 3' end of the strand thus synthesizing the strand in 5'–3' direction.

Since the direction of adding the nucleotide is to the 3' end, therefore the polarity of the template strand will be 3'–5' direction.

Thus, option-A is the correct answer.

after a the power stroke, adp is released, but the cross-bridge formed is still in place. atp then binds to myosin, moving the myosin to its high-energy state, releasing the myosin head from the actin active site.