Chapter 12, Problem 1CONQ

Genes may be protein-encoding genes that encode polypeptides, orthey may not.

Describe three examples of genes that are not protein-encodinggenes.

For protein-encoding genes, one DNA strand is called the template strand, and the complementary strand is called the codingstrand. Are these two terms appropriate for genes that do notencode proteins? Explain.

Do genes that do not encode proteins have a promoter andterminator?

Summary Introduction

To analyze:

The gene is a segment of the DNA, and it can be protein encoding or non-protein encoding. The protein encoding genes encode polypeptides.

a. What are the three non-protein encoding genes?

b. The DNA has a template and complementary strand for protein-encoding genes. The template strand is also known as an antisense strand while the complementary strand is the sense strand or coding strand. Are these terms significant to non-protein encoding genes?

c. Do non-protein encoding genes possess any promoter and terminator?

Introduction:

The main role of DNA is to store hereditary material. Gene is termed as this information is stored in units.

Gene is the segment of the DNA that governs the protein synthesis in an organism.

The genes that are protein encoding are also known as structural genes. These protein-encoding genes carry the amino acid sequence that gets translated into proteins.

Explanation of Solution

The information of DNA into proteins has sequential events termed as central dogma. This central dogma carries out two processes named as Transcription and Translation. The first process is the Transcription; it is the process of copying the information of DNA specifically from the template strand that runs in the direction of $\text{3' to 5'}$ by the mRNA strand. The next step is to decipher the copied code. The translation is the process that decodes the information copied by the mRNA to proteins.

Genes that are protein encoding are also known as structural genes. These protein-encoding genes carry the amino acid sequence that gets translated into proteins. Overall $\text{90\%}$ of the genome has all protein-encoding genes while the rest are non-protein encoding genes.

a. The three non-protein encoding genes are ribosomal RNA (rRNA), transfer RNA (tRNA) and the micro RNA genes. The ribosomal RNA is made to form the functional ribosomes that are crucial factors required to accomplish protein synthesis. Transfer RNA playsan important role in the translation process by recruiting the correct anticodon or amino acids at the translation site. The micro RNA & small interference RNA (siRNA) has vital roles in the regulation of gene expression of eukaryotes.

b. Both the terms are significant to non-protein encoding genes because overall, all the genes undergo transcription process. In this process, the template strand of DNA is copied by mRNA. The template strand of DNA will show a sequence similarity to mRNA except for the bases; T is replaced by U.

c. All the genes must have a promoter and terminator in order to undergo the process of transcription. The initiation of transcription requires the promoter and terminator to stop the process. Hence, the genes that do not encode a protein will also have a promoter and terminator.

Conclusion

All the aspects are determined.