Flashcards
DNA replication
Flashcards do conjunto (20)
- 1what is the role of the DNA replication fork?the region of DNA at which all proteins involved in DNA replication come together to carry out synthesis of daughter strands (party central)
- 22 strands of DNA replicationleading and lagging
- 3leading strandmade continuously from a single RNA primer
- 4lagging strandmade discontinuously- new primer made every few hundred bases
- 5Okazaki fragments1. formed on the lagging template between 100 and 200 nucleotides long. 2. separated by ~10-nucleotide RNA primers and are unligated until RNA primers are removed
- 6what maintains the stability of the replication fork?single stranded binding proteins (RPA) - also stops ssDNA from being degraded by exonucleases
- 7PCNA3 subunits form a circular structure through which DNA passes -maintains the stability of polymerase
- 8bi-directional mechanism of DNA replicationtwo forks form at origin and move in opposite directions-both strands being copied in each direction
- 9telomeresrepetitive sequence at end of chromosomes -protect from fraying
- 10the 4 enzymes of DNA replication1. helicase, 2. DNA polymerase, 3. primase, 4. ligase
- 11helicaseunwinds the double strand, this requires energy to break the H bonds
- 123 DNA polymerase jobs1.copies the strand. 2. moves along the single strands and recruits dNTPs (nucleotide triphospates) to hydrogen bond their partners and helps build a second strand. 3. removes errors
- 13primasean RNA polymerase that is part of an aggregate of proteins called the primeosome. Attaches a small RNA primer to the ssDNA to act as a primer for synthesis (removed later by RNase H)
- 14ligasejoins together two pieces of DNA when DNA polymerase I fills the gaps
- 15what enzyme is responsible for synthesis?DNA polymerase
- 162 requirements for DNA polymerase to work1. needs a primer with a free 3'OH group, 2. it can only act 5'3' direction
- 17DNA polymerase structurehighly conserved. The shape can be described as resembling a right hand with thumb, finger and palm domains.
- 18why do we need DNA replication?in order to copy chromosomes exactly before cell division to ensure new daughter cells have same content
- 19origin of replicationthe point at which the DNA unwinds and the primer binds, usually A-T rich regions
- 20the DNA synthesied from the origin of replication is calleda replicon
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- Genetics FlashCards sobre DNA replication, criado por lumen7 em 11-05-2013.
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