Explain the concept of semiconservative replication and how simultaneous copying of both strands of DNA is accomplished in prokaryotic cells
What will be an ideal response?
Answer: During replication, only one of the two strands is used as a template (called the parental strand) to form a complementary strand called the progeny (or daughter) strand. Therefore, because only one of the two parental strands is needed for replication, it is considered partially (or semi-) conservative. Simultaneous copying of both strands of DNA is accomplished by opening the DNA double helix and copying the DNA in both directions, forming a replication bubble. One of the DNA strands (the leading strand) is continuously copied by DNA polymerase in the 5' to 3' direction. The other strand of DNA (the lagging 3' to 5' strand) must be copied in short fragments, because the direction of synthesis is the opposite of the movement of the replication fork. This occurs because DNA can only be synthesized in the 5' to 3' direction. Synthesis of DNA on the lagging strand must be repeatedly primed and extended, then the RNA primer is removed and replaced with DNA. The final step, which is performed by DNA ligase, is to join all of the DNA fragments together in a completed continuous daughter strand. (The level of detail in this question should be commensurate with the level of detail discussed in class with the students.)
You might also like to view...
Where is rain more acidic in the United States?
1.East Coast
2.Midwest
3.Pacific northwest
4.West Coast
Large blood vessels that supply the spongy tissue of
the penis are __________ in an unaroused male. a. vasodilated b. vasoconstricted c. secreting prostaglandins d. volume reservoirs e. inhibiting testosterone secretion
You want to design a repressor protein mutant. Which protein domain is the best target for preventing binding of the corepressor?
A) DNA-binding domain B) allosteric domain C) promoter domain D) helix-turn-helix domain E) activator binding site
Why is a molecule of H2 more stable than an atom of hydrogen?
A) The H2 molecule shares the 2 electrons in the outermost shell. B) The H2 molecule has 4 electrons instead of 2. C) The H2 molecule has a vacancy in the outermost electron shell. D) Two pairs of electrons are shared in a strong double bond. E) The innermost shell is more stable when it has 1 electron in it.