Mooers Flashcards
What are the Watson-Crick base pairs found in DNA?
G-‐C, A-‐T
What are the Watson-Crick base pairs found in RNA?
G-‐C, A-‐U,
What are the three stages of DNA synthesis?
initiation, elongation, termination
What direction is DNA and RNA synthesized?
The direction is 5’ to 3’ because nucleotides are added to the 3’ end via the 3’OH cleaving the bond between the alpha and beta phosphates
What are the kinds of alternating chemical moieties found in the backbone of polynucleotides?
phosphates and sugars are the alternating moieties
What features dis.nguishes RNA from DNA?
RNA has 2’OH on the ribose ring, has uracil in place of thymine, can form GU base pairs, usually single stranded, can form a large number of different secondary structures.
What is the importance of DNA with respect to DNA synthesis?
It serves as the template strand
What does replisome do?
Makes two daughter strands with the leading and lagging strand at the same time
What does DNA polymerase need?
a template, dNTPs, and a primer
What is released during DNA synthesis?
pyrophosphate
What happens after pyrophosphate is released?
subsequent cleavage the anhydride bond of pyrophosphate by inorganic pyrophosphates
How much energy is released in this reaction? (DNA synthesis -> release of pyrophosphate -> cleavage of anhydride bond of pyrophosphate)
30kJ/mol; this energy help drive DNA synthesis forward
What are the three major problems imposed by DNA helical structure on DNA replication?
supercoiling, primer intimation, and lagging strand synthesis
What are the role of telomeres at the ends of chromosomes?
Telomeres insure that the coding region of chromosomes is fully replicated
How does the synthesis of the DNA daughter strand occurs when the lagging strand is the template for DNA synthesis?
discontinuously as Okazaki fragments
What is the class of nucleotides that are used to stop elongation during DNA sequencinig by lacking a 3’ hydroxyl group?
dideoxyribonuecleotides,
Which pair of pyrimidines in a DNA strand are most vulnerable to fusion by UV light?
T-‐T
Where it the damaged DNA cleaved in nucleotide excision repair (NER)?
both upstream and downstream from the damaged site
What happens during the prophase of meiosis?
homologous recombination
Where does the homologous recombination occur?
between shared sequences in two chromosomal DNAs
What is a transposon?
a chromosomal segment that can undergo transposition (via google)
What are the types of transposition?
simple/direct transposition & replicative transposition
How does simple/direct transposition work?
via cut and paste method; it leaves a double-strand break in the donor strand and it must be repaired
How does replicative transposition work?
via formationg of a cointegrate intermediate where the donor and recipient both end up with copies of the transposon
