Ch 5 Flashcards
Architectural proteins
Help package dna into chromosome
Small genomes composed of
Mostly of protein coding and rna coding sequences
Small genome found in
Viruses archaea bacteria, unicellular eukaryotes
Large genomes found in what organisms
Multicellular and unicellular eukaryotes
Large genome is most made of
Non coding DNA, introns, exons
Nucleous
Main DNA organelle
Eukaryotic have - chromosomes
Multiple
Nucleosome
DNA wrapped around histones
Core histone
Small, positive, basic proteins, two dimers of H3/H4, H2B and H2A
Linker histone
Larger, positive, basic, H1 and H5
The amount of histones in a nucleosome
9 (8 core, 1 linker)
Most eukaryotics package genome with
Histones
- bp wrapped around histones
146 (180 total)
C terminal end functions
Extend histone fold domain, histone-histone interactions, histone dna interactions
N terminal tails features
Lysine and arginine rich, post translational mods cite
Condensin
Promote dna interactions and define shape of chromosome
Condensing ratio
10,000
Chromosome composed of
One linear double stranded molecule of DNA
Centromere
Where the sister chromatids connect
Cohesins
Holds sis chromotids togethet
Ki67
Protien, coats chromosome to make them repel each other
CENP A
Special histone, epigenetically define the position of the centromere
Kinetochore
Spindles attach
Meta centric telomeres
Middle
Acrocentric
Near end
Telocentric
On the end
Topologically associating domain
Chromosome areas that interact with each other to regulate DNA expression
Levels of gene regulation
1 regulatory elements
2 chromatin
3 chromosome position/ nuclear architecture
C value paradox
size of genome does not equal complexity
Intergenic dna
(60% in people) DNA between genes,
Unique copy number,highly repetitive, interspersed elements (transposable)
Gene and regulatory gene sequences amount in human
40%
Endosymbiosis hypothesis
Mitochondria and chloroplasts are derived from primitive free living bacterial organisms
homoplasmy
Genetics/ organelles from only material gamete (mitochondria)
Mitochondrial DNA
Encodes enzymes for ATP production, autophagy, apoptosis, mutations lead to genetic diseases
Lever hereditary optic neuropathy
Mitochondrial disease, early onset blindness
Chloroplast genome
cpDNA, compact, no histomes, minimal genes, dsDNA
Mitochondria genome
MtDNA, compact, no histomes, minimal genes, dsDNA
Intercompartmental/Lateral gene transfer
happens to mitochondria chloroplast, nucleus
Bacterial nucleoid
Circular dna molecule, no histones, mosaic, cations and covalent bonds present, histone-like
Plasmid
Small, ds, circular or linear
Virus and bacteriophage genome
Ds or ss and circular or linear, no histones
Metagenomics
Sequencing entire populations genomes
Mammalian DNA viruses
Infect mammalian cells for replication
two types of genomes
small bacteria (<10 Mb), unicellular eukaryotes (<20 Mb)
large multicellular,
unicellular eukaryotes (>100 Mb)
10-11 nm fiber
represents the nucleosome, where DNA wraps around core histones 10 nanometers in diameter, can fold into 30 nm
DNA is bound to the
histone core via
ionic reactions
Beads-on-a-string
Beads represent DNA wrapped around the histone
core octamer.
String represents the DNA double helix
eukaryotic exceptions to histones
Dinoflagellate small basic non-histone proteins.
Sperm DNA, basic proteins protamine
prokaryotic DNA packing
chromosome, no histones
30 nm fiber
packed tight asf, arranged in zig zag or sulelinoid
loop domains
Further compaction of the DNA into loops that
contain 50-100 kb of DNA
metacentric
centromere in center
Acrocentric
near end of telomere but not quite
telocentric
on end to telomere
chromosomal territories
where the chromosome resides int he nucleus, its location effects it ability to replicate
TAD
contribute to the regulation of gene expression by restricting interactions of cis-regulatory sequences to their target genes.
c value
amount of DNA in genome
-% Is intergenic DNA in humans
60
types of intergenic DNA
unique DNA, repetitive DNA, tandem repeats, satellites, yuh
-% Is gene and gene regulatory DNA in humans
40
Heteroplasmy
describes the situation in which two or more mtDNA variants exist within the same cell
Leber’s hereditary optic neuropathy is caused by
Mutation of mitochondrial genes
common bacterial viruses
Bacteriophage lamda (double-stranded linear genome)
*M13 (single-stranded circular genome)
common mammalian viruses
– Human papilloma virus (circular, double-stranded)
– Simian virus 40 (circular, double-stranded)
– Adenovirus (linear, double-stranded)
