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CORSO DI BIOLOGIA E GENETICA
UNIVERSITA’ DEGLI STUDI DI CATANIA
CdLM Medicina e Chirurgia
A.A. 2014-2015
Docente del corso:
Dott. Davide Barbagallo, Ph.D.
Lodish – Biologia molecolare della cellula
The The DiversityDiversity and and CommonalityCommonality ofof CellsCells
Cells come in an amazing variety of sizes and shapesCells come in an amazing variety of sizes and shapes
Life…andLife…and virusesviruses
At a molecular level, archaea seem to resemble eucaryotes more closely in their machinery for
handling genetic information (replication, transcription, and translation), but bacteria more
closely in their apparatus for metabolism and energy conversion.
The studies that led to the classification of the living world into the The studies that led to the classification of the living world into the
three domains of bacteria, three domains of bacteria, archaeaarchaea, and , and eucaryoteseucaryotes were based were based
chiefly on analysis of one of the two main RNA components of the chiefly on analysis of one of the two main RNA components of the
ribosomeribosome——the sothe so--called small subunit ribosomal RNA. Because called small subunit ribosomal RNA. Because
translation is fundamental to all living cells, this component of the translation is fundamental to all living cells, this component of the
ribosome has been well conserved since early in the history ribosome has been well conserved since early in the history ofof life on life on
EarthEarth
BetweenBetween 10*1010*1066 and 100*10and 100*1066 speciesspecies
All cells share certain structural All cells share certain structural features and carry out many features and carry out many
complicated processes in complicated processes in basically the samebasically the same
way.way.
1) All the cells contain DNA as genetic material
2) All the cells transcribe DNA into RNA
3) All the cells use proteins for catalysis
4) All the cells translate RNA into proteins in the same way
5) All the cells request free energy to survive
6) All the cells use the same basic molecules to function
7) All the cells have got a membrane that separate the “inside” from
the “outside”
Central dogma of molecular biologyCentral dogma of molecular biology
Human_emb_devHuman_emb_dev
Identical twins occur naturally when the
mass of cells composing an early embryo
divides into two parts, each of which
develops and grows into an individual
animal. Each cell in an eight-cell-stage
mouse embryo has the potential to give rise
to any part of the entire animal. Cells with
this capability are referred to as embryonic
stem (ES) cells. ES cells can be grown in the
laboratory (cultured) and will develop into
various types of differentiated cells under
appropriate conditions.
Stem Cells, Cloning, and Related Techniques Offer Exciting Stem Cells, Cloning, and Related Techniques Offer Exciting Possibilities but Raise Possibilities but Raise Some Some ConcernsConcerns
The ability to make and manipulate mammalian embryos
in the laboratory has led to new medical opportunities as
well as various social and ethical concerns. In vitro fertilization,
for instance, has allowed many otherwise infertile couples
to have children. A new technique involves extraction of
nuclei from defective sperm incapable of normally fertilizing
an egg, injection of the nuclei into eggs, and implantation
of the resulting fertilized eggs into the mother.
However, cloning of humans per se has very limited scientific
interest and is opposed by most scientists because of its high
risk. Of greater scientific and medical interestscientific and medical interest is the ability to
generate specific cell types starting from embryonic or adult
stem cells
In 2012 Shinya Yamanaka and John Gurdon were
awarded the Nobel Prize for Physiology or
Medicine for the discovery that mature cells can be converted to stem cells
The Nobel Prize in Physiology or Medicine 2013 was The Nobel Prize in Physiology or Medicine 2013 was awarded jointly to James E. Rothman, Randy W. awarded jointly to James E. Rothman, Randy W.
SchekmanSchekman and Thomas C. and Thomas C. SüdhofSüdhof "for their discoveries of "for their discoveries of machinery regulating vesicle traffic, a major transport machinery regulating vesicle traffic, a major transport
system in our cells"system in our cells"..
http://www.nobelprize.org/http://www.nobelprize.org/nobel_prizesnobel_prizes/medi/medicine/cine/laureateslaureates//
Photo: A. MahmoudJames E. Rothman
Prize share: 1/3
Photo: A. MahmoudRandy W. Schekman
Prize share: 1/3
Photo: A. MahmoudThomas C. Südhof
Prize share: 1/3
The Nobel Prize in Physiology or Medicine 2014 was The Nobel Prize in Physiology or Medicine 2014 was divided, one half awarded to John O'Keefe, the other divided, one half awarded to John O'Keefe, the other
half jointly to Mayhalf jointly to May--Britt Moser and Britt Moser and EdvardEdvard I. I. MoserMoser ""for their discoveries of cells that constitute a for their discoveries of cells that constitute a
positioning system in the brainpositioning system in the brain".".
http://www.nobelprize.org/http://www.nobelprize.org/nobel_prizesnobel_prizes/medi/medicine/cine/laureateslaureates//
Photo: A. MahmoudJohn O'KeefePrize share: 1/2
Photo: A. MahmoudMay-Britt MoserPrize share: 1/4
Photo: A. MahmoudEdvard I. MoserPrize share: 1/4
A Living Cell Can Exist with Fewer Than 500 GenesA Living Cell Can Exist with Fewer Than 500 Genes
Alberts – Biologia Molecolare della cellula
Also genomes evolve: the birth of gene familiesAlso genomes evolve: the birth of gene families
Too many data!Too many data!Help comes from…BioinformaticsHelp comes from…Bioinformatics
The Molecules of a CellThe Molecules of a Cell
Molecular cell biologists explore how all the remarkable
properties of the cell arise from underlying molecular events:
the assembly of large molecules, binding of large molecules
to each other, catalytic effects that promote particular chemical
reactions, and the deployment of information carried by
giant molecules.
Temperatura media di superfice 15°Temperatura minima in cui si sviluppano organismi viventi
-15°
Temperatura massima in cui si sviluppano organismi viventi
+113°
Massima profondità in cui si trovano batteri 3.200 metriMassima acidità in cui è possibile la vita pH 0,00Massima intensità basica ammissibile per la vita pH 11Livello di alcalinità media per la maggior parte degli organismi
pH 5÷8
Massimo livello di radiazioni ionizzanti sopportate da organismi (una dose di 1.000 rad è mortale per l'uomo)
5.000.000 rad/anno
Massimo di sopravvivenza osservata di batteri a bordo di satelliti nelle condizioni estreme dello spazio esterno
6 anni
Massima pressione sopportata da organismi viventi nelle profondità oceaniche (la pressione a livello del mare è di ~1,00 bar)
1.200 bar
Massima salinità sopportata (la salinità media del mare ed anche del sangue umano è del 3,5%)
30%
CONDIZIONI LIMITE DELLA VITA SULLA TERRACONDIZIONI LIMITE DELLA VITA SULLA TERRA
TheThe Miller and Urey experimentMiller and Urey experiment (or(or UreyUrey––Miller experimentMiller experiment))
Considered to be the classic experiment on the origin of origin of lifelife, it was conducted in 1952 and published in 1953
by Stanley MillerStanley Miller and Harold UreyHarold Urey at the University of University of ChicagoChicago
The RNA World And The Origins Of LifeThe RNA World And The Origins Of Life
PNAs probably preceded RNAsPNAs probably preceded RNAs
RNAs may form secondary and tertiary structuresRNAs may form secondary and tertiary structures
RNA as enzymes: RNA as enzymes: ribozimesribozimes
RNA into viroids
Making different kinds of cellsMaking different kinds of cells——muscle, skin, bone, muscle, skin, bone, neuron, blood cellsneuron, blood cells——is not enough to produce the is not enough to produce the
human body. The cells must be properly arranged and human body. The cells must be properly arranged and organized into tissues,organized into tissues, organsorgans, and , and appendagesappendages..
In 1827, German physician Karl von Baer discovered thatmammals grow from eggs that come from the mother’s
ovary.
TowardsTowards MolecularMolecular Medicine: the Medicine: the genomicgenomic andandpostpost--genomicgenomic eraera
http://www.youtube.com/watch?v=slRyGLmt3qc
Human Genome Announcement Human Genome Announcement at the White House (2000)at the White House (2000)
http://www.genome.gov/10001772
The The importanceimportance ofof modelmodel organismsorganisms
LIFE_MOV
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