DNA replication Flashcards
What is the the sequence of the repeating telomere at the end of DNA for humans
TTAGGG
What was the name of the woman who did much of the research in the area of x-ray crystallography for DNA that led to Watson and Crick’s discovery, but received almost no credit?
Rosalind Franklin
What two men were responsible for proving that DNA replicates semi-conservatively?
Messelson and Stahl
In what year did Watson and Crick receive the Nobel Prize?
1962
Who received the Nobel Prize with Watson and Crick?
Maurice Wilkins
In what year did Watson and Crick discover the structure of DNA?
1953
What two nitrogenous bases are purines?
adenine and guanine
What two nitrogenous bases are pyrimidines?
cytosine and thymine
What is the name of the noncoding regions at the end of each DNA strand?
Telomeres
What is the name of the enzyme that extends the length of the telomeres?
telomerase
What happens to the little strand that is left over after the replication has taken place?
It performs a hairpin turn and joins to the bottom strand to prevent the sticky bit from attaching to something else
What are the two methods that are used to proofread the DNA?
DNA polymerase III and nucleotide excision repair
What is the method of attack for nucleotide excision repair?
The enzymes search for abnormalities in the shape of the helix, and when found, excise the section around the error, and then DNA polymerase III fills in the section with the proper nucleoides
What mechanism does DNA polymerase use to go backwards and proofread the strand?
3’-5’ exonuclease
What is a nucleotide called before it is added to the DNA strand?
nucleoside triphosphate
What determines the 3’ end?
the OH group at the end of the deoxyribose sugar
What determines the 5’ end?
The phosphate group
What is the length of one full revolution of DNA?
3.4 nm
What is the length between two nucleotides in DNA
.34 nm
In what direction does the replication strand always travel?
5’-3’
What are three steps in cloning genetic DNA in a bacterial plasmid?
- Take the DNA with the sequence you are interested in and chop it up
- Insert the different pieces into different bacteria
- Find the bacteria that has the characteristic of the sequence you were after, isolate it and grow a bunch
What are restriction enzymes?
They cut DNA at certain sequences with a certain shape (sticky or blunt)
summarize Polymerase Chain Reactions (PCR)
A procedure that uses different levels of heat to denature the strands, then anneal the primers, extend the primers, and replicate the DNA. It can be used to replicate large amounts of a certain sequence in a very short period of time
