Lec. 25 - DNA Flashcards
Describe the structure, shape, and function of DNA.
The structure of DNA is a double helix shape, and it is composed of smaller nucleotides. Its function is to carry the genetic info that determines the traits and characteristics of an organism.
Explain why DNA replication is considered to be semiconservative.
It is because of the way the process ensure the accuracy of genetic information transfer from one generation of cells to the next.
Explain the process of DNA replication.
It starts with initiation, which is where DNA unwinds and replication forks form. Then theres elongation which is when the RNA primers are synthesize, and DNA polymerization takes place, leading and lagging strands also take place here. Lastly is termination, where replication is completed.
Describe the function of Primase, DNA Helicase, DNA Polymerase, DNA Ligase.
Primase is an RNA polymerase responsible for synthesizing short RNA primers during DNA rep. Helicase is an enzyme that is responsible for unwinding and separating the double stranded DNA molecule into two single strands during DNA rep. Polymerase is a group of enzymes that catalyze the synthesis of new DNA strands by adding nucleotides to the DNA chain. Ligase is responsible for joining or sealing breaks in the sugar phosphate backbone of DNA strands.
Differentiate between complementary and antiparallel regarding, DNA strands.
Complementary is when the specific bases pair between nitrogenous bases on opposite DNA strands. Antiparallel is when the two DNA strands run parallel to each other but in different directions.
Explain what is meant by the replication fork and how this differs in prokaryotes and eukaryotes.
The replication fork is a structure where the double stranded DNA separates into two single strands that serve as templates for the synthesis of new DNA strands. In prokaryotes, DNA replication initiates at a single origin of replication. In Eukaryotes, DNA replication occurs in the nucleus.
Explain how Okazaki fragments are created and how they are resolved.
Okazaki fragments are created due to the antiparallel nature of DNA and the mechanism of DNA synthesis by DNA polymerase. They are resolved by removing RNA primers, filling gaps, and sealing the fragments.
Differentiate between the leading and lagging strands and their relation to the antiparallel nature of DNA.
The leading strand is synthesized continuously, the lagging strand is synthesized discontinuously.
