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Lecture 1

BIO 1530 Lecture Notes - Lecture 1: Centriole, Archaea, Mitochondrion


Department
Biology
Course Code
BIO 1530
Professor
Jon Houseman
Lecture
1

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Proterozoic Eon
Third Eon
End up with cells that have complexity to them
Domain of life
Sister group of eukarya is bacteria or archea? Archea
Archea because Packaging of chromosomes both use histon proteins to package up the
material like the eukarya which shows theyre related
Conversion into protein both us methionine
Became apparent archea and eukarya are sister groups.
Whether theyre branched or unbranched isn’t something that happened
First simple forms were from the bacterium group
Luca sitting at the bottom was aenorobic
Eukaryote Autaporphies
Nuclear envelope- Origin: Batceriums were also increasing in size, if plants were
smooth this means not enough plasma membrane so they started inviginated . provides
extra membrane for extra volume. As this invagination occurred it also surrounded the
nucletoide , put a double plasma membrane around neucleus which is the nuclear
envelope, pores exist. Ultimately this invagination surrounds the nucleotide, important
because everything happening in one mix of cytoplasm , we have effectively divided the
cell into 2 parts, into what functions theyre going to do , within nuclear envelope
optimized all biochemistry of life that is associated with DNA replication and
transcription of DNA into message . Nucleus allows to have specific place for replication
and transcription. Cytoplasm becomes spot for processes of life.
Endosymbiosis of bacterial Cells: Mitochondria
The mitochondria is a eukaryote characteristic , it is a bacterial cell that has set up a
relationship inside to provide energy
We have bacteria getting bigger then others , and bacterias feeding off others , can use
other bacteria as a nutrient for itself . If they were going to consume something itd be the
smaller bacterium.
There is a bacterium that consumes another bacterium with unique set of biochemical
processes. This bacterium that is absorbed by being engulfed so has two plasmas , did not
get ingested but because of a weird luck , this batcterium was a specialist at taking 3
carbon compound and adding them to two carbon groups and made proton pumps to
make ATP. <- Krebb cycle
What was fortuous was that the cell that engulfed it was digesting glucose sugars ,
splitting them in half and producing three carbon compounds then gave it to mitochondria
which gave it energy and surplus energy was passed on to cell.
When two organisms work together to each others mutual benefit
This occurs throughout all of living world.
Worked really well , bacterium ended up in eukaryote and was superior cell to how it
functions.
Had an advantage , as result mitochondrial cell lives in there and multiplies in it numbers
and when cell divides the mitochondria is divided between daughter cells. Seems to only
happen once

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Sequences is highly stable over evolutionary time
Still has original dna in it and its circle
Similar in some of most primitive plants, animals and fungi.
One bacterial genome that incorporated into a mitochondria and all eukaryotes are all
descendants of this one event
We know from circular genome and protein etc tht it’s a bacterium , ribosomes are
smaller sized too
We’ve been able to track changes , mitochondria is a big event in eukaryotes.
Later along , it happens again and chloroplast is created , which is specified for
photosynthesis
Ocean was full of organic material so heterotrophs are first , plants cannot generate atp
from light , plant must use its own glucose.
Multiple chromosomes and diploidy
Change in architecture of genome , only one replication point , it takes a while to make
duplicate point
Instead of circular genome we have many linear genomes , replicating fork on
chromosomes. We can replicate genome much faster
Diploidy-Eukaryotes have paired chromosomes , each trait is coded as alleles and there is
2 copies of each one on each chromosome
Eukaryote Variability Random Segregation: When we take reduction of diploid into
haploid cell we end up with swapping around of chromosomes. Mix that creates genetic
variation , x2 will tell us amount of combinations(x being chromosomes)
Eukaryote genetic recombination Crossing over-When sister chromatids come together in
miosis and theyre all wrapped up tightly together they can break and reeaneell on
opposite arm of chromosome . Further mixing of the chromosome strands creating more
variability . Can cross and recross also which shows huge variability. Genetic variation
comes from this
Centrosomes
Cant have diploid without centriole
Centriole: produce cytoskeleton of cell. Made of tubule dymers arranged in a row that
creates a hollow cylinder where there is 3 arranged around the central core where 9
components are present . Entirely protein structure. Cylindr of microtubules.
Microtubules: Tubulant protein in dymer , centriole base the cylinders are arranged where
theres 9 around central core. Centriole always has specific structure. 2nd one right angle to
it. Sitting at bottom with adjacent to it base where it adds double pairs and builds hollow
cylinder to the top.The little structure adds and makes it grow
This structure builds microtubules.
Polarity happens
Negative end is adjacent to centriole ,
Positive end is where growing occurs
centriole controls building of strands and can also disassemble from opposite end.
Molecular motors travel through microtubules. Two of them important:
Dyenin and Kinesin- Directional based on polarity of the strand and burn ATP when they
walk , interact with strand and burn ATP.Grabbing things and moving them around the cell.
Runs everything in a cell.Attaches to chromosomes to pull them apart for mitosis and
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