U4 LEC: GENOMES AND VARIANTS Flashcards
Bacterial Genome consists of?
- nucleoid
- bacterial genomes
- chromosomal domains
- bacterial chromosomes
Compact bacterial chromosome
Nucleoid
About a third of the volume of the cell, has many independent chromosomal domains
Bacterial genomes
Supercoil loop of DNA, randomly distributed
Chromosomal domains
Majority are circular, some are linear
Bacterial chromosomes
Linear bacterial chromosomes
- multiple1-Mb chromosomes (Borrelia species)
- 8-Mb chromosomes (Streptomyces species)
Circular bacterial chromosomes are mostly represented by?
plasmids
1-Mb chromosomes
Borrelia species
8-Mb chromosomes
Streptomyces species
These proteins assist in the level of compaction in bacterial genome.
Nucleoid-Associated Proteins
How do NAPs help in organization of chromosome?
bridging, wrapping or bending, causes level of compaction
NAPs
- HU
- SMC complex
- FIS
- IHF
- H-NS
NAPs
Small protein subunit that bridges interconnecting sites between genome
H-NS
NAPs
H-NS causes ______ with linear DNA and fold with each other
bridging
NAPs
Antiparallel coiled hinged domain, wraps around to linear DNA causing it to coil
SMC complex
NAPs
Appearance of SMC complex
Safety pin appearance
NAPs
Abundant NAP, causes interlinkage between successive joints or part of linear DNA and causes to coil
HU
NAPs
Alters and facilitates the formation of loops
IHF
NAPs
Causes compact and organization but separate molecule that causes bridging with linear DNA
FIS
Capsid is made up of?
capsid proteins wrapped around RNA or DNA
Capsid follows general symmetry which includes
- Icosahedral
- Helical
Capsid follows what structure?
- symmetrical
- quasisymmetrical
Most common capsid structure
helical structure
Virus that attacks bacteria
Bacteriophage
Structures of the Bacteriophage
- head (where the genome is located)
- tail (attachment point)
Virus may possess a capsule made up of?
lipid
T/F: Larger organisms have a larger genome.
True
How many genes do we have
25,000
1 gene will contain how many base pairs?
less than 1000
Largest known human gene, facilitates muscle injury repair and found in the X chromosome
Dystrophin (2.4M bases)
T/F: 99.9% of nucleotide bases are exactly the same in all people.
True
The Human Genome Project only took blood from?
5 people
More than _____ genes have an unknown function
12,000
Histone protein that has the most modification, most diverse and most variable
H2
This refers to when histone is removed, the gene is turned off
Knockout
Core histone protein, knockout phenotype
H2A
For DNA repair, sperm defect in meiosis
H2A.X
Gene activation and silencing, embryonic infertlity
H2A.Z
Unique Animal Chromosomes
- Lampbrush Chromosome
- Polyetylene chromosomes
These chromosomes are found in some amphibians
Lampbrush Chromosomes
Lampbrush Chromosomes
Found specifically in what amphibians?
Pleurodele amphibians
Lampbrush Chromosomes
Similar appearance to?
test tube brush
Lateral loops that extrude from the chromomeres at certain prositions
Lampbrush Chromosomes
Lampbrush Chromosomes
Appear at meiosis stage in which chromosomes resemble a?
series of beads on a string
Lampbrush Chromosomes
The loop is an _______ DNA segment that is actively _______.
extruded, transcribed
Lampbrush Chromosomes
Present in urodele amphibians
Oocytes (Diplotene prophase chromosomes)
These chromosomes are found in insects such as common house flies in their larvae
Polytene chromosomes
Polytene Chromosomes
Appearance
different protruding chromosomes with different synapsis, many arms
Polytene Chromosomes
Usually found at?
interphase nuclei
Polytene Chromosomes
Useful for?
analysis of many facets of eukaryotic interphase chromosome organization and the genome as a whole
Polytene Chromosomes
Develop from chromosomes of?
diploid nuclei by successive duplication of each chromosomal element
Gene Size of Rickettsia prowazekil
1.11Mb, 834 genes
Gene Size of Homo sapiens
3,300 Mb, 25,000 genes
Unique sequence, only 1 copy per haploid
Nonrepetitive
Nonrepetitive represents what regions?
coding (exons)
Introns contain?
repetitive DNA
T/F: The length of the nonrepetitive DNA increase with overall genome size.
True
Increase genome size in higher eukaryotes reflects?
increase amount and proportion of repetitive DNA
T/F: Genome size and gene number is weaker in prokaryotic genomes than in eukaryotic genomes.
False
weaker sa eukaryotic
Moderately Repetitive Sequences
- Interspersed Elements (Repetitive Transposed Sequences)
- Tandem Repeated DNA (VNTRs and STRs)
under Moderately Repetitive Sequences
- Transposons
- SINEs
- LINEs
Most common moderately repetitive sequences
Transposons
selfish or junk DNA
Transposons
function on their own pero walang ambag aw
Short sequences of DNA, ability to move to new locations in the genome
Transposons
Opposite of transposons
Retrotransposons (difference in size)
Retrotransposons include?
- Short interspersed elements
- Long interspersed elements
<500 base pairs, present in 500 times or more
SINEs