The RNA synthesized on one of the DNA strands is:
a. mRNA
b. tRNA
c. rRNA
d. all of these.

Verified step by step guidance

1. Step 1: Understand that RNA is synthesized from a DNA template strand during the process called transcription.
2. Step 2: Recognize that the primary RNA product synthesized directly from the DNA template is messenger RNA (mRNA), which carries the genetic code from DNA to the ribosome for protein synthesis.
3. Step 3: Note that transfer RNA (tRNA) and ribosomal RNA (rRNA) are also types of RNA, but they are not directly synthesized as the initial transcript from the DNA strand; they are processed and assembled differently.
4. Step 4: Conclude that the RNA synthesized directly on one of the DNA strands during transcription is mRNA.
5. Step 5: Therefore, the correct answer is the RNA type that is the direct transcript of DNA, which is mRNA.

Key Concepts

Types of RNA

RNA molecules include mRNA, tRNA, and rRNA, each serving distinct roles in protein synthesis. mRNA carries genetic information from DNA to ribosomes, tRNA brings amino acids during translation, and rRNA forms the core of ribosome structure.

Transcription Process

Transcription is the synthesis of RNA from a DNA template strand. During this process, RNA polymerase reads one DNA strand to produce a complementary RNA strand, which can be mRNA, tRNA, or rRNA depending on the gene transcribed.

DNA Template Strand

The DNA template strand is the specific strand of DNA used by RNA polymerase to synthesize RNA. It is complementary to the RNA produced, ensuring accurate transfer of genetic information during transcription.