Endoplasmic reticulum Function Synthesizing proteins, lipids, and steroids Two types: rough ER and smooth ER Key components LOTS of membranes Vesicles Cisternae Ribosomes
Golgi apparatus Function Key components Modify and package proteins and lipids made in the rough ER Key components Flattened stacks Cisternae Vesicles
Mitochondria Function Key components Energy-producing machines! ATP Regulation of metabolism Stores calcium Key components Inner and outer membranes Cristae Matrix Ribosomes Own genome (from mom)
Lysosomes Function Key components Digest biological molecules Increased acidity compared to the rest of the cell pH ~4.5 Key components LOTS of enzymes Proton pumps (hydrogen)
Cytoskeleton Function Key components Architecture of the cell Help localize organelles Facilitate cell shape changes Key components Actin microfilaments Microtubules Intermediate filaments
Chloroplasts Function Key components Photosynthesis Produce sugar using sun’s energy Key components Chlorophyll Lots of membranes
Figure 1-20 Essential Cell Biology (© Garland Science 2010)
Figure 1-21 Essential Cell Biology (© Garland Science 2010)
Algae biofuels Sunlight + Water + CO2 Sugar processed into lipids (oil)
Light Microscope Resolution = 200 nm (0.2 µm) Wavelength of light: 0.4 – 0.7 µm Cells can be alive, fixed, and/or stained
Fluorescence Microscopy Fixed or live cells Light of a specific wavelength is projected onto a sample Light is emitted from the sample based on the kind of dye/probe it is labeled with
http://www.youtube.com/watch?v=j87y7EAj8qE
Confocal Microscopy Cells need to be fixed Producing a 3D image of a sample by scanning through it layer by layer
Electron Microscope Resolution = 2 nm Dead cells are fixed with heavy metals Transmission EM Image is produced by electron scattering as they go through a thin sample Scanning EM Image is produced by electron scattering as they bounce off of the sample
$45,000-150,000
Why do we use them?
Model Organisms Escherichia coli (Prokaryote) Saccharomyces cerevisiae Drosophila melanogaster Arabidopsis thaliana Zebrafish Mus muscularis Eukaryotes
Advantages of Model Organisms E. coli Prokaryote Cheap and easy to grow in bulk Kept as frozen stock Generation time = 30 minutes Store and express foreign DNA Lots of mutants Entire genome sequenced Transformation of exogenous DNA
S. cerevisiae Eukaryote Has two sexes Cheap and easy to grow Mating experiments Cheap and easy to grow Kept as frozen stock Generation time = 2 hours Store and express foreign DNA Lots of mutants Entire genome sequenced
Arabidopsis thaliana Plant Generation time = 6 weeks Large number of offspring (thousands+) Foreign DNA can be introduced Lots of mutants Entire genome sequenced Not much “junk” DNA
Drosophila Invertebrate Has two sexes Fairly cheap and easy to grow Mating experiments Fairly cheap and easy to grow Generation time = 12 days Large number of offspring (hundreds+) Foreign DNA can be introduced Lots of mutants tinman (no heart), lilliputian (small), dreadlocks, cheap date, swiss cheese, lava lamp, lunatic fringe, radical fringe, manic fringe Entire genome sequenced
C. elegans Invertebrate, multi-cellular Has two sexes Mating experiments Cheap and easy to grow Kept as frozen stock Generation time = 3 days Large number of offspring (hundreds+) Fate of all 959 cells known Store and express foreign DNA Lots of mutants Dumpy, uncoordinated, bag-o-worms Entire genome sequenced
Zebrafish Vertebrate Has two sexes Generation time = 3 months Mating experiments Generation time = 3 months Large number of offspring (hundreds+) Good number of mutants available floating head, half stoned, dynamo, tiggywinkle hedgehog, one-eyed pinhead Eggs are clear Can observe developmental changes
Mus muscularis Vertebrate Has two sexes Generation time = 10 weeks Mating experiments Generation time = 10 weeks Good number of mutants Foreign DNA can be introduced Can “knock out” genes to study human diseases Entire genome sequenced