Chapter 13 Flashcards
Bacteriophage
Viruses the infect bacteria. DNA (or RNA) enclosed by a protective coat of protein.
Frederick Griffith
Worked with strains of bacterium. Found that when he mixed dead remains of the pathogenic strain with living cells, some of the cells became pathogenic.
Hershey and Chase
Showed that DNA is the genetic information of a phage by conducting an experiment which showed that the phage injected only DNA into cells during infection.
Erwin Chagraff
Found that DNA composition varies from one species to the next and that in any species the number of A/T bases are equal and the percentage of G and C bases are equal.
Antiparallel
Subunits of DNA run in opposite directions.
Helicases
Enzymes that untwist the double helix at the replication forks.
RNA primer
The short initial nucleotide strand.
Primase
The enzyme that starts an RNA chain with a single RNA nucleotide and adds RNA nucleotides one at a time using the parental DNA as a template.
DNA polymerase
Enzymes that catalyze the elongation of new DNA at the replication fork. Builds the new strand from 5’ to 3’ and moves along the template strand from 3’ to 5’.
Leading/Lagging strands
DNA polymerase synthesizes the leading strand continuously moving toward the replication fork. For the other new strand, DNA polymerase must work in the direction opposite the replication fork.
Okazaki Fragments
A series of segments that the lagging strand is synthesized as.
DNA ligase
Joins the gaps between the okazaki fragments.
Mismatch Repair
Enzymes correct errors in the base pairings of DNA.
Nuclease
Cuts out and replaces damaged stretches of DNA.
Telomeres
Special nucleotide sequences at the ends of Eukaryotic chromosomal DNA molecules. Postpone the shortening of DNA.
