Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
The origin and evolution of cells, focusing on the similarities between prokaryotic and eukaryotic lives, the endosymbiotic theory, and the role of experimental models in cell biology. It discusses the concept of the last universal common ancestor (LUCA), the differences between prokaryotic and eukaryotic cells, and the endosymbiotic origin of mitochondria and chloroplasts.
Typology: Schemes and Mind Maps
1 / 13
This page cannot be seen from the preview
Don't miss anything!
Same basic molecular mechanisms governs prokaryotic and eukaryotic lives, indicating that all present-day cells are descended from a single first ancestor
Prokaryotic cells
Cells
Eukaryotic cells
3. Prokaryotes
LUCA last universal common ancestor Prokaryotes Archaea
Bacteria
Eukaryotes
All organisms existing today come from the “LUCA” cell. This cell is the beginning of the tree of life, then, we now classified all organisms in three main domains: The Bacteria, the Archaea (both procariotic cells) and the eucaryote domains. Bacteria and archaea diverge early in the evolution and, from archaea, evolve the eukaryotic domain.
Cells
3. Eukaryotic cells
a) Nucleus b) Mitochondria c) Golgi Apparatus d) Vacuole e) Chloroplast f) Lysosome g) Cell Membrane h) Endoplasmic Reticulum i) Ribosome j) Cell Wall
Cytoskeletom The structural framework of the cell: Maintains the internal organization of the cell. It is made of protein filaments extending throughout the cytoplasm
Cell shape Cell movement Intracellular transport Organelle positioning
Structures for chromosomes movement
Membrane-enclosed subcellular organelles
Invaginations of the plasma membrane
Many cell structures are formed by internal membranes, so the acquisition of these internal membranes allowed the cell to isolate some regions to perform certain functions independently from the rest of the cell
Some organelles evolve from invaginations of the plasma membrane:
The genome of eukaryotes arose from a fusion of archaeal and bacterial gemones
The initial endosymbiotic relationship of bacterium living inside an archaeum organism gave rise not only to mitochondria (or chloroplast) but also to the genome of eukaryotic cells containing genes derived from both procaryotic ancestors.
1.2. The endosymbiotic theory
As a result of all this processes the genome of eucaryotic cells is a mix of bacteria's and archaeal related genes. Curiously most eukaryotic genes implicated in formational processes, such as DNA replication, transcription and protein synthesis are related to arqueal genes. By contrast, most eucaryotic genes related to basic cell operational processes such as glycolysis and amino acid biosynthesis derived from bacteria genes. So, the endosymbiotic theory not only explains the origin of mitochondria and chloroplast but also the origin of the eucaryotic genome.
1.2. Cell specialization, The development of multicellular organisms
yeast
The ciliated protozoan Paramecium Amoeba Dictyostelium
Understanding the mechanisms that control the growth and differentiation of such a complex array of specialised cells starting from single fertilized egg, is one of de mayor challenges facing contemporary cell and molecular biology
1.3 Experimental models in cell biology
2 Yeasts , the simplest model for eukaryotic cells (Saccharomyces cerevisiae)
From this model we learnt how an eucaryotic cell Works:
3 Caenorhabditis elegans (c.elegans) A multicellular nematode (a worm)
4. Drosophila melanogaster - Genome: 180 millions base pair - 14,000 genes - Reproduction cycle: two weeks
Very useful organism for genetic experiments, the relationship between genes and genomes has been extensively studied in this organism
1.3 Experimental models in cell biology
5. The Zebrafish (26000 genes)
A very interesting model to study the cardiac system.
An adult human is composed of about 10 13 cells, all of which are derived by cell division from a single fertilized egg.
2.Human cells in culture divide about once per day. Assuming that all cells continue to divide at this rate during development , how long would it take to generate an adult organism?
3.Do you think, that adult humans take longer to develop than these calculation might suggest?
