Unit 3-Molecular Genetics Lesson 2 3.0 Flashcards
What is the limitation of DNA polymerase regarding the ends of DNA strands?
DNA polymerase cannot replicate or repair a small portion at the end of the lagging strand.
What happens when the RNA primer of the lagging strand is removed?
There is no 3’ OH- group available on the last nucleotide, preventing DNA polymerase from adding more nucleotides.
What is the consequence of DNA polymerase not being able to add nucleotides to the ends of DNA strands?
The new strands of DNA continue to shorten after each round of replication.
In which type of cells does the shortening of DNA strands occur during replication?
This only occurs in Eukaryotic cells, as they contain linear DNA.
What is the role of telomeres in DNA replication?
Telomeres protect important genes and prevent their degradation during replication.
How do telomeres change with each round of DNA replication?
The telomeres will also shorten as the ends of the DNA strands shorten.
How does termination of replication differ between prokaryotes and eukaryotes?
In prokaryotes, termination occurs when the circular DNA is complete; in eukaryotes, replication is initiated at multiple sites.
What causes the gap at the 3’ end during replication?
The gap exists where RNA primers have not annealed, resulting in a shorter strand with each replication cycle.
What are telomerases and their function?
Telomerases are enzymes that exist at the end of each strand, composed of repetitive sequences that prevent the loss of important genetic information.
What are the three main stages of DNA replication?
The three stages are Initiation, Elongation, and Termination.
What happens when the replication forks fuse together?
They form a continuous strand of newly synthesized DNA.
What do the two new daughter DNA molecules contain after replication?
Each molecule contains a newly synthesized copy of DNA and a parental copy.
What causes errors during DNA replication?
Errors can occur due to mispairing of nucleotides, strand slippage, and the involvement of many enzymes in the replication process.
What is an example of mispairing of nucleotides?
Examples include pairing A with C or T with G, which changes the DNA shape and makes it unstable.
What happens during strand slippage?
Either the newly synthesized strand or the template strand may loop out, causing extra nucleotides to be added or deleted.
