intro Flashcards
Why are cells small?
in order to transfer materials from outside the cell into the cell, to work quickly, surface to volume ratio must be maximized
Large cells are…
multinucleated
Complexity of cells
not random! ordered and consistent eg: PCD
Cell Biology is…
Reductionist–knowledge of the parts explains the whole
Tools used to look at cells
Modern Compound microscope
transmission electron micrscope
Robert Hooke
“cell” using first compound microscope in 1665
Anton van Leeuwenhoek
Made really good lenses, first to describe many single celled organisms “animalcules”
Matthias Schleiden & Theodore Schwann
first two tenants of cell bio
- all organisms composed of one or more cells
- cell = structural unit of life
Pasteur
environment causes growth, not spontaneous if left in closed vessel–lead to 3rd tenant
3rd tenant
cells can arise only by division from an existing cell
–Rudolf Virchow
Why are these exciting times for cell bio?
low cost genome sequencing
Stems cells and gene regeneration
take own cells and derive tissues from them
Problem with growing full organs
complex! not just a bundle of tissue–have specific organization
synthetic biology
make life from scratch–could disrupt the 3rd tenant
J Craig Venter–alter genome in bacteria so it has a new set of characteristics
creating artificial DNA–new base pairs
Why are chemical interactions so important in the cell?
because at the molecular level all events are triggered by another
T or F: movement of molecules is smooth
F–make use of brownian movement in order to fit in to small spaces because the cell is very crowded
Basic cell properties:
complex genetic program and means to use it reproduce acquire and utilize energy carry out chem rxns engage in mechanical activities interact with environment self regulation evolve
timeline of life
photosynthetic bacteria–cyanobacteria–eukaryotes
cyanobacteria importance
took in CO2 and spewed out O2 which was toxic to many organisms but lead to the great oxygenation event 2.3 bya
Initial eukaryotes
stuck together and began to specialize in function leading to first multicellular organisms
Importance of cambrian time period
cambrian explosion–lots of life occured
3 domains of the phylogenetic tree of life
Bacteria, Archaea, and Eucaryota
LUCA
Last universal common ancestor (branch pt)
Theory of endosymbiosis
anaerobic heterotrophic prokaryote engulfed an aerobic prokaryote which was not digested because it helped the cell by making ATP and thus created an aerobic heterotrophic prokaryote with a mitochondria
T or F: chloroplasts came before mitochondria
F–some engulfed photosynthetic cyanobacteria which lead to the creation of cholorplasts after mitochondria
What happened after an aerobic prokaryote was engulfed?
pre-eukaryote started getting lots of folds which lead to the primitive eukaryote w/ a nuclear envelope precursor
Characteristics common to prokaryotes and eukaryotes
similar plasma membrane constituted of lipids
both us DNA, similar genetic code
similar transcription and translation mechanisms
similar metabolic pathways
(plants and cyanobacteria–similar photosynthesis)
LUCA had to have all of these things
Unique characteristics of Eukaryotes
nucleus--stores DNA separate chromosomes membraneous organelles presence of mitochondria complex cytoskeleton ability to phagocytose and endocytose material diploidy or polyploidy cell division, mitosis--mitotic spindle sexual reproduction--meiosis
