Term
each cell:
# of human chromosomes
length (m) of DNA
# DNA subunits (the bases)
about # of genes coding for proteins |
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Definition
46 chrom
2m
3 billion dna subunits
23,000 genes code |
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Term
Analogy: Human genome and a book
The book is over -- words long
The book is bound in --volumes of --pages each
~-- words (3 letters/word) per page
The book fits into a cell nucleus the size of a --
all cells but- |
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Definition
one billion words
5,000 vol.
300pg
300 words
pinpoint
red blood celss dont have dna |
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Term
| % of exons in human genome- improtance |
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Definition
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Term
| Human cell nucleus diameter ≈ |
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Definition
| 0.00001 m point and4 zeros 1 |
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Term
| ~1013 cells in human body x 2 m DNA/cell |
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Definition
| = 2 x 1013 m of DNA per adult |
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Term
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Definition
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Term
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Definition
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Term
| Underwinding of DNA induces strain that can be resolved by |
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Definition
| supercoiling and/or strand separation |
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Term
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Definition
| DNA molecules of same length with differing amounts of supercoiling |
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Term
Topoisomerases catalyze-
important role in- |
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Definition
the increase or decrease of DNA supercoiling
Important role in DNA replication and packaging |
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Term
| Type I topoisomerases break |
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Definition
| only one of the two DNA strands |
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Term
| In bacteria and eukaryotes, generally relax DNA by |
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Definition
| removing - supercoils (↑ Lk) |
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Term
| Type II topoisomerases break |
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Definition
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Term
Type II topoisomerases in bacteria aka=
can introduce -
Uses-- energy source
Target of -- |
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Definition
dna gyrase
supercoils
ATP
targe antibiotics |
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Term
Type II topoisomerases in EUK
Can relax -- but cannot--
inhibiors used in-- |
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Definition
relax both + and - DNA
cannot underwind DNA (induce supercoils)
chemotherapy |
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Term
| in euk supercoils are introduced via |
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Definition
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Term
| Because supercoiled DNA molecules are -- compact than relaxed molecules, they migrate-- rapidly during gel electrophoresis. |
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Definition
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Term
Chromatin (in eukaryotes)=
Same for bacteria? |
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Definition
= the DNA of the nucleus together with its associated proteins
Bacteria have another assembly of protein and DNA |
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Term
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Definition
| are the basic building blocks of chromatin in eukaryotes and archaea |
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Term
# of bp's of histone core of nucleosome
# of bp's of linker dna
Is it for EUK, Archae, or PROK? |
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Definition
146 core
55 linker
EUK & ARCHAE ONLY |
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Term
| AA content consistent with histone binding to DNA |
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Definition
| Hi LYS and ARG (+AA) content consistent with binding of histones to - charges on phosphodiester backbone of DNA |
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Term
| Formation of nucleosomes satisfies the requirements of |
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Definition
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Term
| Chromatin assembly 1st level- |
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Definition
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Term
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Definition
| a higher-order organization of nucleosomes |
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Term
| Levels of DNA compaction. |
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Definition
DNA
Beads on a string nucleosomes
30nm fiber
one loop (75k bp)
one rosette (6 loops)
one coil (30 rosettes)
two chromatids |
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Term
Euchromatin vs. heterochromatin
in nucleus?
confirmation tight or open?
Transcriptionally active? |
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Definition
both in nucleus- hetero esp in mitochondria
Euch= open confirmation =active
Hetero= compacted chromatin fibers inactive |
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Term
| Euchromatin contains mostly |
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Definition
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Term
| Functional significance of supercoiling: (3) |
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Definition
1.Compacts DNA
nderwinding facilitates access of
2.DNA-modifying proteins to single strands
3.Regulates interaction of DNA and proteins like transcription factors and DNA polymerases |
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