All Flashcards
What is the effect of telomere shortening?
Telomere shortening leads to the eventual cessation of cell division and contributes to aging.
What happens if Helicase is inhibited?
If Helicase is inhibited, the DNA double helix cannot unwind, preventing DNA replication.
What happens if DNA Polymerase III makes an error and it is not corrected?
If DNA Polymerase III makes an error and it is not corrected, it results in a mutation in the newly synthesized DNA strand.
What is the effect of the 5' to 3' directionality of DNA polymerase on the lagging strand?
The 5' to 3' directionality of DNA polymerase causes the lagging strand to be synthesized discontinuously in Okazaki fragments.
What is the consequence of not having single-strand binding proteins?
Without single-strand binding proteins, the separated DNA strands would re-anneal or form secondary structures, hindering replication.
What happens if ligase is non-functional?
If ligase is non-functional, Okazaki fragments on the lagging strand will not be joined, resulting in fragmented DNA.
What is DNA replication?
The process by which cells copy their DNA before dividing, ensuring genetic information is passed on.
What is Helicase?
An enzyme that unwinds the double helix and breaks the hydrogen bonds between the bases during DNA replication.
What is DNA Polymerase III?
An enzyme that adds new DNA nucleotides to the 3' end of the primer, following the template strand during DNA replication. It works in the 5' to 3' direction.
What are Okazaki fragments?
Short fragments of DNA synthesized on the lagging strand during DNA replication.
What are Telomeres?
Protective, non-coding sequences at the ends of chromosomes that shorten over time, contributing to aging.
What is DNA Polymerase I?
An enzyme that removes RNA primers and replaces them with DNA nucleotides during DNA replication. It also proofreads and fixes mistakes.
What are the key differences between the leading and lagging strands in DNA replication?
Leading Strand: Synthesized continuously in the 5' to 3' direction, following the replication fork. | Lagging Strand: Synthesized discontinuously in the 5' to 3' direction, away from the replication fork, forming Okazaki fragments.
Compare and contrast the functions of DNA Polymerase I and DNA Polymerase III.
DNA Polymerase III: Primarily responsible for adding nucleotides to the growing DNA strand during replication. | DNA Polymerase I: Removes RNA primers and replaces them with DNA nucleotides; also involved in proofreading.
Compare DNA replication in eukaryotes and prokaryotes.
Eukaryotes: Occurs inside the nucleus. | Prokaryotes: Occurs in the cytoplasm.
What is the difference between conservative and semiconservative replication?
Conservative: The original DNA molecule remains intact, and a completely new DNA molecule is synthesized. | Semiconservative: Each new DNA molecule consists of one original strand and one newly synthesized strand.
Differentiate between the roles of primase and ligase.
Primase: Synthesizes short RNA primers to initiate DNA synthesis. | Ligase: Seals the gaps between Okazaki fragments on the lagging strand.