18 Questions
Why did Meselson and Stahl label the DNA strands with a heavy isotope of nitrogen (15N)?
To support the semiconservative model
How did Meselson and Stahl's experiments support the semiconservative model of DNA replication?
By eliminating the dispersive and conservative models
What is the role of origins of replication in DNA replication?
They separate the two DNA strands
In eukaryotes, why are there hundreds or thousands of origins of replication on a single chromosome?
To ensure faster replication of large eukaryotic chromosomes
Why is it essential for histones to be disassembled and reassembled during DNA replication in eukaryotes?
To allow DNA polymerase to replicate DNA bound to histones
What is the function of topoisomerases like gyrase in DNA replication?
To break, swivel, and rejoin DNA strands ahead of replication forks
What is the function of telomeres in eukaryotic chromosomes?
Delay the erosion of genes near the ends of DNA molecules
Why is the shortening of telomeres hypothesized to be the cellular basis for aging?
Immortal cells like stem cells have constant telomere length
Which enzyme is responsible for catalyzing the lengthening of telomeres in germline cells?
Telomerase
What is the purpose of circular chromosomes in prokaryotes?
Allow for more efficient DNA replication
How do telomeres differ from other parts of the chromosome?
They are dispensable and do not code for proteins
What role does telomerase play in protecting organisms according to the text?
Limits the number of cell divisions
What is the main function of DNA polymerase in DNA replication?
Adding nucleotides to the free 3' end of the new DNA strand
Which enzyme is responsible for sealing Okazaki fragments together in DNA replication?
DNA ligase
Why does repeated replication of linear eukaryotic chromosomes produce shorter DNA molecules with uneven ends?
Telomerase continuously extends the telomeres during replication
What is the term used to describe the complex that includes all components needed for DNA replication?
Replisome
Which model describes the lagging strand of DNA folding into a loop during replication?
Trombone model
In which type of chromosomes does the usual replication machinery provide no way to complete the 5' ends?
Linear chromosomes
Learn about DNA replication mechanisms in eukaryotic cells and the significance of telomeres in preventing the erosion of genes near the ends of DNA molecules. Understand why this process is crucial for eukaryotic cells compared to prokaryotes.
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