Inheritance Flashcards
What are viruses that infect bacteria called?
Bacteriophages
DNA is a polymer of nucleotides, consisting of what?
Nitrogenous base, sugar and phosphate group
4 nitrogenous bases?
adenine, guanine, thymine, cytosine
X-ray crystallography of DNA determined what?
Helical structure of DNA
what nitrogenous pairing was consistent with Xray data?
purine + pyrimidine
What are enzymes that untwist double helixes at replication forks?
Helicases
What enzyme corrects overwinding ahead of replication forks?
Topoisomerase
What enzyme can start an RNA chain from scratch and adds RNA nucleotides using parental DNA as reference?
Primase
which end is the starting point of new DNA strands?
3’ end
What enzymes catalyze elongation of DNA at a replication fork?
DNA polymerase
(uses a primer and parental DNA strand to elongate)
Rate of elongation in bacteria & humans?
500 nucleotides per sec in bacteria
50 nucleotides per sec in humans
Nucleoside phosphate used to add adenine?
dATP (deoxy Adeonsine truohisohate)
Lagging strands replicate as segments called what?
Okazaki fragments joined together by DNA Ligase
What enzyme is used for nucleotide excision repair (incorrectly paired nucleotides)?
Nuclease (cuts out an dreplaces damaged stretches of DNA)
Eukaryotic chromosomal DNA molecules have special nucelotide sequences at their ends called?
TELOMERES (delays erosion of genes near ends of DNA molecules) - it protects the chromosomes by getting cut off instead of important information getting cut off
