Term
GENOME
-definition?
-example? |
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Definition
=complete set of genetic material in a particular compartment
ex) all DNA contained in human gamete |
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Term
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Definition
| typically a single, circular chromosome |
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Term
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Definition
nuclear genome (complete set of chromosomes that reside in nucleus: haploid)
-also mitochondrial DNA
-chloroplast DNA (in plants) |
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Term
genetic material
-function?
-location? |
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Definition
-to store info needed to produce characteristics of an organism
-stored in chromosomes (in sequences of bases in DNA molecule) |
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Term
| Viruses are not living organisms because? |
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Definition
| -they rely on host cell (no energy producing enzymes, ribozomes, or organelles) |
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Term
| genetic material of viral genome? |
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Definition
nucleic acid
-can be DNA or RNA |
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Term
| difference between bateriophage & eukaryotic virus? |
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Definition
bateriophage- virus that infect bacteria, capsid may also contain sheath, base plate, & tail fibers
euk viruses- infect eukaryotes, also an envelope consisting of membrane embedded with spike proteins |
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Term
self-assembly
-definiton
-example |
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Definition
if virus has a simple structure, nucleic acid + capsid protein spontaneously bind in order to make mature virus particles
ex) TMV |
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Term
directed assembly
-definition
-example |
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Definition
if a virus has a complex structure, it requires non-capsid proteins in order to make mature virus particles (scaffolding proteins + non-capsid proteases
ex)T2 bacteriphage |
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Term
| responsible for the cleavage of capsid proteins into smaller units? |
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Definition
| non-capsid proteins that act as proteases in directed assembly |
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Term
| how might directed assembly be beneficial to a virus? |
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Definition
| it allows it to produce a more complex viral product |
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Term
bacterial chromosomes
-found?
-copies? |
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Definition
-circular
-found in nucleoid (direct contact with cytoplasm-no membrane)
-usually have a single type of chromosome but more than one copy
-can have 1-4 identical chromosomes per cell
-each chromosome occupies its own distinct nucleoid region |
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Term
| Scientists have identified a new bacterial species which typically has 6-10 nucleoids per cell. How many copies of the bacterial chromosome would you expect are present in each cell? |
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Definition
6-10 chromosomes
-each chromosome occupies its own nucleiod region |
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Term
Regions found in bacterial chromosomal DNA
-types?
-majority? |
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Definition
-structural genes, intergenic regions, origin of replication
-mostly structural genes (nucleotide sequences that encode proteins). are very long because of introns. |
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Term
bacterial chromosomal DNA folded __X to fit within bacterial cell?
-by? |
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Definition
1000 fold
by loop domains & supercoiling |
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Term
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Definition
| =DNA conformations, either positive or negative supercoiling |
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Term
underwining causes?
overwinding causes? |
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Definition
underwinding-> negative supercoil
overwinding-> positive supercoil |
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Term
| chromosomal DNA in living bacteria is ____________ supercoiled. |
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Definition
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Term
| underwinding of DNA causes? |
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Definition
-negative supercoiling
-which creates tension on DNA strands
-tension released by strand separation
->enhances genetic activity (replication & transcription) |
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Term
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Definition
| relaxes negative supercoils |
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Term
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Definition
AKA DNA gyrase
-relaxes positive supercoils, introduces negative
-uses 2 ATP -> 2 negative supercoils
-upper, lower jaw
-untangles DNA molecules following DNA replication (topo for euk, gyrase for bac) |
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Term
| bacteria has how many origins of replication? |
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Definition
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Term
| shape of eukaryotic chromosomes? |
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Definition
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Term
| which contain more DNA, eukaryotes or bacteria? and why? |
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Definition
eukaryotes
-contain more genes |
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Term
| location of choromosomes in eukaryotes? |
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Definition
nucleus
-separated cellular compartment |
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Term
| DNA complex in eukaryotes? |
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Definition
chromatin
-contain eukaryotic chromosomes
-can change its shape and composition during life of cell |
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Term
Which of the following structures of a eukaryotic chromosome is not primarily composed of DNA?
A)Telomeres.
B)Origin of replication.
C)Kinetochore.
D)Centromere. |
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Definition
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Term
| 3 regions required for eukaryotic chromosomal replication & segregation? |
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Definition
1. origins of replication
2. centromeres
3. telomeres |
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Term
| sizes of eukaryotic genomes vary substantially due to? |
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Definition
| repetitive DNA sequences present in copies |
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Term
centromere
-found?
-how many?
-role?
-function?
-types? |
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Definition
-in eukaryotic chromosome
-each chromosome contains ONE centromere
-role in proper segregation of chromosomes during mitosis and meiosis
-function as site for formation of kinetochore
-point centromere vs regional centromere |
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Term
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Definition
-formed at site of centromere just before & during early stages of mitosis & meiosis
=composed of a group of cellular proteins that link the centromere to the spindle apparatus during mitosis and meiosis |
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Term
telomeres
-location?
-function? |
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Definition
-found at end of linear chromosomes
-prevent chromosomal rearrangements & chromosomal shortening (via exonuclease) |
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Term
| where are genes located in eukaryotes? |
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Definition
- between centromic and telomeric regions along eukaryotic chromosome
-typically have few hundred to several thousand different genes |
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Term
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Definition
-take up majority of eukaryotic chromosome
-found in more complex eukaryotes
-are very large because of introns
-are typically UNIQUE (only found once) |
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Term
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Definition
found in structural genes, cause length
=non-coding intervening sequences |
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Term
| In fruit flies, a gene called bicoid controls embryonic development. What type of DNA would you expect this gene to be? |
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Definition
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Term
| humans have __% of unique sequences on their genome |
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Definition
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Term
| "Au" sequences are example of? |
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Definition
highly repetitive sequences (each copy is relatively short)
-makes up 10% of total human DNA
-ancestral gene: 7SL RNA gene |
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Term
tandem array
-definition?
-location? |
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Definition
=when some moderately & a lot of highly repetitive sequences are clustered togeher
-common in centromeric regions
ex)Drophilia |
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Term
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Definition
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Term
| How do DNAs with a slow rate of renaturation compare to those with a high rate of renaturation? |
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Definition
| Slow renaturing DNAs are less repetitive than fast renaturing DNAs |
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Term
| diameter of eukaryotic cell vs. nucleus? |
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Definition
10-100 micrometers
2-4 micrometers
-> must be greatly folded and packaged |
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Term
nucleosomes
-definition
-diameter?
-shortens by? |
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Definition
=repeating structural unit within eukaryotic chromatin. A double-stranded segment of DNA wrapped around an octamer of histone proteins (2 copies of 4)
-requires 146-147 bp
-diameter: 11nm
-shortens DNA by 7 fold |
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Term
| Correct order of levels of chromatin compaction? |
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Definition
| Nucleosomes, 30 nm fibers, radial loop domains. |
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Term
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Definition
what DNA wraps around to form nucleosome
-2 copies of 4 subunits: H2A, H2B, H3, H4 |
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Term
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Definition
=a globular domain and a flexible, charged amino terminus (aka amino terminal tail)
-basic: a lot of positively charged lysine & arginine amino acids |
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Term
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Definition
-an amino acid
-role in binding to DNA
-found in basic histone proteins
-in histones: form electrostatic & H bonding with phosphate groups along DNA backbone
- |
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Term
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Definition
-a histone
-found in most eukaryotic cells
-aka linker histone
-binds DNA in linker region between nucleosomes |
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Term
| responsible for linking nearby nucleosomes? |
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Definition
| H1 & non-histone proteins |
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Term
| Histone proteins bind to both the core DNA and the linker DNA. T/F? |
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Definition
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Term
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Definition
| an enzyme that cuts DNA backbone |
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Term
| DNase protection experiments were used to support the beads on a string model of chromatin structure. Which of the following statements would apply to DNase protection experiments? |
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Definition
| Proteins which are tightly bound to DNA can prevent DNase digestion. |
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Term
| 30nm fiber shortens DNA by? |
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Definition
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Term
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Definition
=interactions between 30nm fibers and filamentous network of proteins
-2 parts: nuclear lamina & internal nuclear matrix
-proteins (MARs & SARs) responsible for compacting chromatin into radial loop domains during interphase |
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Term
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Definition
-part of nuclear matrix
=collection of fibers that line the inner nuclear membrane
-composed of intermediate filament proteins |
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Term
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Definition
-part of nuclear matrix
-connected to nuclear lamina and fills interior of nucleus |
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Term
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Definition
loops of the 30nm fiber of chromatin
-anchored to nuclear matrix
-formed during interphase |
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Term
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Definition
-protein of the nuclear matrix
=matrix-attachment regions
=bond to specific proteins in nuclear matrix and form chromosomal loops (AT bases) |
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Term
| advantages of attaching radial loops to nuclear matrix? |
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Definition
-compaction
-organization (chromosomes organized into discrete chromosome territory) |
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Term
| variability of compaction levels during interphase? |
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Definition
-heterochromatin (tightly compacted, transriptionally inactive)
-euchromatin (less condensed, transcriptionally active) |
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Term
| 2 types of heterochromatin? |
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Definition
1. constituitive: always heterochromatic & permanently inactive. usually contain highly repetitive DNA sequences & tandem repeats
2. facultative: chromatin that can interconvert between hetero and euch
ex)1 X in female converted to Barr body (which his heterochromatic) |
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Term
| example of constitutive heterochromatin?? |
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Definition
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Term
| example of facultative heterochromatin? |
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Definition
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Term
| Supercoiling generally prevents information within the DNA from being read. T/F? |
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Definition
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Term
| Histone proteins bind to both the core DNA and the linker DNA. T/F? |
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Definition
| False, The core DNA binds to the histone octamer, and histone H1 binds to linker DNA. |
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Term
| Active genes are probably located in _________ regions of DNA. |
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Definition
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Term
| Condensin plays a critical role in the formation of metaphase chromosomes. T/F? |
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Definition
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Term
| During Interphase, most all of eukaryotic chromosomal DNA is found in which form of chromatin? |
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Definition
| euchromatin (active, less condenses) |
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Term
| Centromeres are which form of chromatin? |
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Definition
| heterochromatin (inactive, highly condensed) |
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Term
| By the end of M phase, sister chromatids are entirely ________? |
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Definition
| heterochromatic--> most transcriptional activity ceases |
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Term
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Definition
=cohesin
-a multiprotein complex
-acts on interphase->metaphase chromosomes) |
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Term
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Definition
-multiprotein complex
-prior to M, outside of nucleus
-As M begins, coats chromatids and transformed euchromatin-->heterochromatin |
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Term
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Definition
-found in condensin & cohesin
=structural maintenance of chromosomes
-use ATP to catalyze change in DNA structure
-work with topoisomers to promote changes in structure
-dimers with V-shaped structure |
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Term
| sister chromatid separation occurs when? |
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Definition
-during anaphase
-when cohesin at the centromere is degraded |
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Term
| sister chromatid arms free when? |
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Definition
-by end of prophase
-when cohesin is degraded from arms (but remains at centromere) |
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