UNIT 2 REVIEW Flashcards
prototroph
bacteria having the nutritional requirements of the nml/wildtype
auxotroph
mutant strain of bacteria lacks the ability to make a specific compound; will not grow unless the growth medium contains specific nutrients
minimal medium
contains only nutrients required by protophoic (wildtype) bacteria
complete/enriched medium
contains supplemental nutrients + basic nutrients to support fastidious or mutant growth requirements
F factor
fertility factor
(an episome allowing gene exchange b/w bacteria - first observed by Esther Lederberg)
Do auxotrophs or prototrophs require extra nutrients?
auxotrophs (mutants)
Diff. b/w plasmids & episomes
episomes are larger than plasmids and can incorporate into the chromosome and remain integrated
Esther Lederberg
Discovered Fertility Factor (F Factor)
Transformation
bacteria can take up naked DNA from its environment into its cell
OriV
origin of replicaion on a plasmid
OriV vs OriC
OriC is the orgin of replication of a chromosome and OriV is the origin on a plasmid
replicon
segment of DNA undergoing replication
How many OriC in bacteria?
usually 1
Number of OriC in eukaryotes
Multiple per chromosome
Both RNA and DNA synthesis occur ___ to ___.
5’ to 3’
leading strand
continuous replication following the replication fork b/c we can keep adding to the 3’ end
lagging strand
sythesis occurs in direction opposite the movement of the replication fork #discontinoussynthesis #okasakifragments
Topoisomerase II AKA
gyrase
Topoisomerase II AKA Gyrase
works ahead of DNA helicase to cut double stranded DNA temporarily and prevent supercoiling & prevents helicase from getting to far ahead of itself
The 3 Stages of a Bacterial Cell Cycle
B Period (birth)
C Period (chromosome replication)
D Period (cell division)
Two Main Stages of Eukaryotic Cell Division
Interphase & Mitosis
3 Stages of Interphase
G1, S, G2
4 Phases of Mitosis
Prophase
Metaphase
Anaphase
Telophase
What happens between Telophase and Interphase (G1)?
Cytokinesis
Conservative, SemiConservative, and Dispersive Replication
Conservative: One daughter molecule contains both strands of parent DNA
Semi-Conservative: Each daughter molecules contains 1 strand of DNA from the parent and 1 new strand
Dispersive: parental dobule helix is broken into double stranded segments and then reassembled into complete double helicies with parental and progeny DNA interpsersed
Watson & Crick
proposed method of replication based on structure
Meselson & Stahl
determiend DNA is replicated in a semi-conservative method
Theta Replication
repliation in circular DNA
Do plasmids replicate bidirectionally?
No.
Do bacterial chromosomes replicate bidirectionally?
Yes.
Discontinuous replication produces ____.
Okasaki fragments
dnaB is a ________.
helicase
dnaA
binds to oriC and helps to open the DNA initiallhy so dnaB (helicase) can fit in and unwind it further
DNA Polymerase ____ synthesizes the daughter strand
III
Expalin Briefly how DNA Polymerase I, II, and III work together.
I removes the primers and starts replication, III (yes, 3) is the major replicative polymerase adding nuclotides, then II functions to repair any mistakes.
What are the 4 major nucleases in Eukaryotes?
alpha - create primer to initiate replication
delta - DNA synthesis on lagging strand
epsilon - DNA synthesis on LEading strand
gamma - mitochondrial DNA replication
DNA Polymerase II exonuclease activity is
3’ to 5’
DNA polymease III exonuclease activity is
3’ to 5’
DNA Polymerase I exonuclease activity is
5’ to 3’
In linear DNA molecules, which end gets shorter after each round of replication?
both ends
heterochromatin
highly compacted chormatin (telomeres/centromerers)
euchromatin
less compacted chromatin (arms/crossingover)
How many base pairs per nucleosome?
200 per nucleosome + 30 base pairs between each nucleosome = ~230
