Topic 2 Flashcards
cell
the fundamental unit of life
Robert Hooke
1665, first coined the term “cell” while viewing cross-sections of cork in primitive light microscope; invented first simple light microscope
Anton van Leeuwenhoek
1674, viewed “animalcules” in pond water and bacteria from scrapings from his teeth and identifies different cell types, magnified objects up to 300x
3 points of the cell theory
- all organisms are composed of one or more cell
- the cell is the structural and functional unit of life
- cells can arise only by division from a pre-existing cell
Theodor Schwann
animal tissues
Jakob Schleiden
plant tissues
Rudolph Virchow
cellular pathology
4 basic macromolecules
nucleic acid, proteins, lipids, carbs
requirements for formation of first cell
- organic molecules
- molecules for catalysis of chemical reactions and self-replication (RNA)
- a barrier between the internal and external cell environment (phospholipids)
Stanley Miller
1950, spontaneous formation of organic molecules
In present-day cells, DNA is the….., RNA is…… and proteins…..
genetic material, a carrier of info, carry out most functions
prokaryotic cells
lacks a nuclear envelope
eukaryotic cells
have a nucleus
viruses
neither prokaryotic or eukaryotic; can’t metabolize without host
archaebacteria
closest to first cell
cyanobacteria
largest, most complex prokaryote generating energy through photosynthesis
plants evolved from…
cyanobacteria
plasma membrane
forms a selective barrier
nucleus
contains genetic info
mitochondria
sites of oxidative metabolism; contains circular DNA
lysosomes
metabolic compartments for digestion of macromolecules
peroxisomes
various oxidative reactions
endoplasmic reticulum
a network of intracellular membranes that functions in processing and transports proteins and synthesis of lipids
golgi apparatus (euk)
sorts and transports proteins for secretion and site of lipid synthesis
golgi apparatus (plants)
synthesis of polysaccharides that compose the cell wall
cell wall
rigid layer of polysaccharides surrounding a cell membrane
primary component of cell membrane
chitin in fungus and cellulose in algae and higher plants
chloroplasts
sites of photosynthesis; contains circular DNA
vacuoles
digestion of macromolecules and storage of waste products and nutrients
cytoskeleton
- provides structural framework
- movement of entire cells and intracellular transport
cytoskeleton composed of..
actin filaments, intermediate filaments, microtubules
yeast
simplest eukaryote
epithelial cells
form sheets that cover surface of body and line internal organs; specialized for protection, secretion, absorption
connective tissue
bone, cartilage, and adipose tissue
fibroblasts
fill spaces between organs and tissues in body
blood tissue
contains red blood cells and white blood cells
nervous tissue
composed of supporting cells and nerve cells which are specialized to transmit signals
muscle cells
responsible for production of force and movement
E.coli
most thoroughly studied bacteria
E. coli pros
simple and ease of propagation, divide every 20mins, small genome, carry out reactions in simple media
yeast pros
small genome, divides every 2 hours, same approaches as e.coli
c. elegans
entire lineage know, easily grown and subjected to genetic manipulations
drosophila pros
easily maintained and bred
xenopus laevis
all stages of development can be studied, early vertebrate developments and eggs develop outside mother
zebrafish
easy to maintain, reproduce rapidly, amenable to genetic manipulation, transparent embryos
mouse
easy to keep in lab, complete genome sequence
basic tool of cell biology
light microscope
resolution
ability to distinguish objects; constrained by wavelength of visible light
light microscopy (bright field)
light passes directly through cell
-requires killing of cells, cutting thin cross-section, staining
light microscopy (phase-contrast/differential interference-contrast)
convert variations in density or thickness into contrast that can be seen without staining
-allow viewing of live cells
fluorescence microscopy
sensitive method to study intracellular distribution of molecules; visualization without staining
how do you visualize using fluorescence microscopy
fluorescent markers, dyes and proteins (GFP)
a major technological breakthrough in visualization of living cells was…..
discovery of green fluorescent proteins (GFP) - allowed visualization without staining of specific molecules and structures in living cells
confocal microscopy
specialized form of fluorescent microscopy; allows focus on a single plane in specimen; provides much sharper image and multiple images can be reconstructed into a 3D image
confocal yellow stain
microtubules
confocal blue stain
actin
confocal red stain
nucleus
electron microscope people
Claude, Porter, Palade; 1940s/50s
electron ……… compared to light
much greater resolution
wavelengths of ….. shorter than……
electrons, visible light
transmission electron microscopy (TEM)
passes beam of electron through specimen to form image on fluorescent screen
scanning electron microscopy
electron beam reflects off sample surface (coated w metal) and proves a 3D image
subcellular fractionation
separates and isolates organelle by size and density for use in biochemical studies
primary cultures
first cell cultures established from a tissue (limited number of division before death)
permanent (immortal) cell
embryonic stem cells or cells derived from tumours that may proliferate indefinitely in culture