DNA Replication Flashcards
What is the Replisome?
The replisome is a complex of enzymes working together during DNA replication.
What is the role of helicases in DNA replication?
Helicases unwind DNA during replication.
What are telomeres and why are they important?
Telomeres are non-coding repeating sequences at the end of chromosomes. They shorten with each cell division and when they run out, the cell stops dividing (senescence).
What is DNA rearrangement and why is it important?
DNA rearrangement is when DNA is not faithfully copied as is. It helps add diversity to the vertebrate immune system
gene amplification
results from repeated rounds of DNA replication at specific region of genome.
–> increases the no of copies of genes w/in cell
function of DNA-binding proteins in replication
DNA-binding proteins stabilize unwound DNA strands during replication
What do topoisomerases do during DNA replication?
Break and rejoin DNA strands to relieve tension from unwinding
clamp loading and sliding clamp proteins?
help DNA polymerase bind and remain associated with the DNA template
somatic hypermutation
a cellular mechanism by which the immune system adapts to the new foreign elements that confront it
(essentially b-cells mutate to create diverse b-cells that can recognize and neutralize pathogens)
what 5 enzymes make up the replisome? Name and list their basic functions
- DNA pol (syn new DNA)
- Helicase (unwind DNA)
- clamp-loading & sliding- clamp proteins: (Help bind and stay binded)
- DNA-binding proteins (stabalize unwound DNA)
- Topoisomerase: (relieve tension from unwinding)
Senescence
When telomeres run out, the cells stop dividing
Cancer & Telomeres
Telomerase** the enzyme that extends telomeres, in certain mutated cells (like cancer cells) is overly active.
(stem cells also have active telomeres, but not like cancer cells)
