Answer:
DNA ligase
Explanation:
<em>The biochemist must have left out DNA ligase enzyme.</em>
<u>The DNA ligase enzyme is able to catalyze the formation of phosphodiester bonds and as such, capable of joining strands of DNA together to form a single strand.</u>
The numerous DNA segments of a few nucleotides long observed by the biochemist must have been the replicated product of the lagging DNA strand. The lagging strand is replicated discontinuously in short strands because the DNA polymerase enzyme can only elongate primers in 5' to 3' direction. The short segments are known as Okazaki segments and are usually joined together to form a whole strand by the DNA ligase enzyme.
Hence, the missing component is the DNA ligase.
Tumor cells are cells that divide relentlessly, forming solid tumors or flooding the blood with abnormal cells.
Answer: Promoter
Explanation:
Transcription is the first step in gene expression which consists of copying the DNA sequence of a gene to produce a RNA molecule. There are enzymes called <u>RNA polymerases which perform this process of transcription</u>. These enzymes bind nucleotides (the monomers which are part of the nucleic acids) to create a RNA strand using a DNA strand as a mold.
A promoter is a region of DNA that controls the initiation of transcription of a given portion of DNA to RNA. Therefore they promote the transcription of a gene. <u>The promoter region is composed of a specific sequence of DNA located just where the starting point of the DNA transcription is</u> and contains the information needed to activate or deactivate the gene it regulates. <u>The promoter has a binding site for the RNA polymerase enzyme </u>in charge of mRNA synthesis and when it recognizes this site, transcription begins.
