Genetics DNA III: The replication of DNA by Nathan H Lents, Ph.D. Reading Quiz Teach with this A human body contains between 10 and 100 trillion cells. Each cell within a body contains the same DNA sequence (except on rare occasions). The reason each DNA sequence is identical is because the triphosphate nucleotides are the same in all cells. new DNA strands are made only by copying pre-existing DNA strands. there is only one pattern a DNA sequence can follow. there are only four nucleotides that make up a DNA sequence. Which statement below BEST explains why biochemists often use in vitro reconstitution as a research method? It allows them to recreate a cellular event in isolation and manipulate it as necessary. It allows them to recreate and observe a cellular event in a natural environment. It allows them to recreate and observe a reproductive event within the human body. It allows them to recreate a biochemical event using only synthetic materials. In the late 1970s, two research groups independently discovered what was responsible for separating the two strands of a DNA helix within a cell. The mechanism was identified as an enzyme called DNA ligase. an enzyme called DNA polymerase. an enzyme called DNA helicase. nucleotide triphosphates. Select the comparison below that is accurate. DNA helicase is like a word processor. Nucleotide triphosphates are like wrecking balls. DNA polymerase is like a copy machine. Phosphate bonds are like building blocks. Study the table shown below. Identify the sequence of discoveries that occurs in the correct order. A B C D Which of the following could NOT have been discovered if the Kornberg team had not first identified the primer responsible for starting DNA synthesis? Nucleotides occur in complementary base-pairs. DNA synthesis is semi-conserative. Replication begins at specific origins. DNA synthesis is unidirectional. Why are triphosphate nucleotides required for DNA synthesis? Each phosphate contributes energy and a total of three are needed for each step. The bridge between each nucleotide must be three phosphates long. The breaking of the high-energy bond between the 2nd and 3rd phosphates provides the energy for DNA synthesis. Only triphosphate nucleotides fit into both DNA helicase and Okazaki fragments. Inside a cell, the primers that are necessary for DNA polymerase to start working are made of RNA. DNA primase. lagging strands. Okazaki fragments. Score Quiz