Download Chapter 12, part 2 | BIOL 2004 - Genetics and more Quizzes Genetics in PDF only on Docsity!
what is involved in DNA replication
cell replicationmutationrecombination-->base pairing--
enabling DNA replication TERM 2
the template is...
DEFINITION 2 single stranded DNA TERM 3
nature of DNA
DEFINITION 3 semi-conservative using N15 labeled nucleotidesthis is used/good for ultracentrifugation TERM 4
ultracentrifugation
DEFINITION 4 used to separate certain organelles from whole cells for further analysis of specific parts of cells. TERM 5
origin of replication
DEFINITION 5 where replication beginsmarked by special nucleotide sequenceprokaryote- singleeukaryote- many
DNA synthesis
occurs at replication forkinvolves: helicase enzyme- for unzipping 2 strands by using ATP energy DNA polymerase TERM 7
DNA polymerase
DEFINITION 7 needs a primer to work (a short length of RNA) so it can start synthesis of new DNA strandalways in the 5'-->3' directionuses ATP, CTP, GTP, and TTP (not AMP, CMP, etc.)accurateself-replicatingvery fastdoes both synthesis of DNA and proofreadingDNA fork is asymmetricunique structure TERM 8
DNA replication fork
DEFINITION 8 asymmetric- there is a leading and lagging strandpieces of DNA made (Okazaki fragments) in the lagging strandcontinuous DNA strands made in the leading strand TERM 9
semi-conservative replication
DEFINITION 9 each strand serves as a template TERM 10
3 types of replication
DEFINITION 10
- linear2. theta3. rolling circle
what kind of DNA replication is best to study?
bacterial (prokaryotic); one circular naked DNA; more simple especially in regards to structure of chromosome and proteins involvedE. coli TERM 17
initation
DEFINITION 17 1st step of replicationinitiation protein binds to origin of replication and causes a short cut TERM 18
unwinding
DEFINITION 18 proteins involved: helicase; several SSB proteins too TERM 19
elongation
DEFINITION 19 primase- makes primer RNA; synthesizes a short stretch of RNA, providing a 3 OH group to which DNA polymerase can add DNAprimosome = DNA primer (RNA + helicase)DNA polymerase type I, III works for the two strandsligase- seals DNA fragments, double strand formation and joining of Okasaki fragments TERM 20
termination
DEFINITION 20 blocks the two ends of DNAassembly on nucleosome; no enzyme involvedtelomerase- makes the telomers at the 2 ends
telomerase
synthesizes telomeres as the replication fork reaches the endthese telomere ends attract telomerase TERM 22
importance of telomerase attraction to
telomers
DEFINITION 22
- replication of lagging strand to complete2. protect the ends of the chromosome by making a cap TERM 23
DNA repair
DEFINITION 23
- need repair if DNA was damaged due to chemical and physical agents (mutagens)2. need repair if nucleotides are mismatched; remove wrong ones and put the correct ones TERM 24
what leads to the need for DNA repair
DEFINITION 24 DNA damage due to depurination and deaminationDNA polymerase and recombinations during gamete formations; homologous and non-homologous chromosome recombinationTE need repair by DNA polymerase TERM 25
Eukaryotic DNA replication
DEFINITION 25 not well understood; similar to prokaryotes, but still different
somatic cells and telomerase activity
they have little to no telomerase activity and have a short and discontinuous lifearchaea and eukaryotes are more similar and cannot replicate extensively for long TERM 32
molecular basis of recombination
DEFINITION 32
- crossing over2. translocation TERM 33
crossing over
DEFINITION 33 homologous recombinationHoliday model accomplished by a single-strandstrand displacement--> branch migration and relocation --> single holiday junctionresult: branch migration TERM 34
translocation
DEFINITION 34 non-homologousdouble strand breaks and 2 holiday junctionsenzymes required: revolvase (A, B, C, C, D), single strand binding (SSB) protein, ligase, DNA polymerase, Gyrase
