Illustration below is a dna segment which constitutes a gene. 1. Identify the shaded and unshaded region
2. Explain how these genes are expressed. 3. How is the gene different from prokaryotic gene in its expression.
Answers
Answer:
The DNA replicase of bacteriophage T4 is a loosely assembled multiprotein complex that is comparable in composition to the replicases of bacteria and humans (15, 20, 26). Among its components are a DNA polymerase (gp43), product of phage gene 43, a sliding clamp (gp45), a clamp loader (gp44/62 complex), a single-stranded DNA-binding protein (Ssb, gp32), a primase (gp61)-helicase (gp41) complex, a helicase-primase assembly factor (gp59), RNase H (gprnh), DNA ligase (gp30), and probably other proteins. The sliding clamp in the T4 replicase is a gp45 trimer, and the clamp loader is a heteromeric complex consisting of four gp44 subunits and one gp62 subunit that are tightly bound together (11). In addition to their essential roles as accessory proteins to DNA polymerase, gp45 and the gp44/62 complex interact with the T4-modified transcriptional machinery of the Escherichia coli host and are required for the coupling of phage DNA replication to transcription during the late stages of phage development (28, 36).
Gene expression is the process by which the instructions in our DNA are converted into a functional product, such as a protein. It acts as both an on/off switch to control when proteins are made and also a volume control that increases or decreases the amount of proteins made.
When more protein is required, more transcription occurs. Therefore, in prokaryotic cells, the control of gene expression is mostly at the transcriptional level. ... In eukaryotic cells, the DNA is contained inside the cell's nucleus and there it is transcribed into RNA.