AP BIOLOGY

THE MOLECULAR BASIS OF INHERITANCE

DNA MAKES RNA MAKES PROTEIN

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
During transcription, only one strand of DNA serves as a template.
A
true
B
false
Explanation: 

Detailed explanation-1: -In transcription, a region of DNA opens up. One strand, the template strand, serves as a template for synthesis of a complementary RNA transcript. The other strand, the coding strand, is identical to the RNA transcript in sequence, except that it has uracil (U) bases in place of thymine (T) bases.

Detailed explanation-2: -DNA is double-stranded, but only one strand serves as a template for transcription at any given time. This template strand is called the noncoding strand. The nontemplate strand is referred to as the coding strand because its sequence will be the same as that of the new RNA molecule.

Detailed explanation-3: -Transcription uses one of the two exposed DNA strands as a template; this strand is called the template strand. The RNA product is complementary to the template strand and is almost identical to the other DNA strand, called the nontemplate (or coding) strand.

Detailed explanation-4: -Answer and Explanation: Only one strand of DNA is used during transcription because if both strands will transcribe, they will make different mRNA copies that may code for different proteins, and is not possible to make different proteins from single DNA molecules.

Detailed explanation-5: -During DNA replication, both strands of the double helix act as templates for the formation of new DNA molecules. Copying occurs at a localized region called the replication fork, which is a Y shaped structure where new DNA strands are synthesized by a multi-enzyme complex.

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