08/29/2012 Notes● Cell biology emphasizes how cells function (primarily Eukaryotes),while Physiology looks at how cells become specialized andfunctionally integrated.● Reductionist approach – the whole is the sum of its parts; take forexample an animal cell. Contains many organelles (mitochondria,etc.) Mitochondria contain double membrane, a matrix, and manycompartments with unique compositions of various proteins (whichare all made outside in the cytoplasm). Experimentally make proteinfrom mRNA and then put in test-tube with mitochondria to see how itfinds its place in the compartment.● Liver for example has two pathways consisting of cells for breakdownof glucose into subunits but also gluconeogenesis (for example afterperiod of starvation).● Office Hours: Monday (11:00 – 12:00 BPS 1245), Friday (10:00 –11:00 BPS 2249)● Read Lab Manual on Elms.08/31/2012 Notes● Work of Greek physicians such as Hippocrates and Golen left legaciesof ideas that had influence of medicine up to the middle ages. Someof their modeled ideas, however, slowed down the progress ofmedicine.● Hippocrates established many fundamental ideas of how physiciansshould practice (even applied today – the recording and exchange ofmedical data). He believed that there is a rational basis for thedisturbances due to diseases; i.e. no mystical factors.● Four humors or fluids that the Greek believed were in us (Blood,black bile, yellow bile and limb). They believed that the change inproportion of these fluids that affected personalities, as well asresponsible for ailments. For example, he believed that fevers were aresult of excess blood, so they would draw their blood.● Discovery of Eukaryotic Cells: Examine the work of 17th centuryEnglish physician Percivall Pott.● Around this time many Italian physicians established relationshipsbetween diseases or conditions and an individual’s profession (suchas neurological issues associated with painters, etc.)● At this time, physicians began to take case histories of patients andwhen going back to studying them, made important discoveries.● Percivall Pott was an English physician at St. Bartholomew and manydiseases are named after him (like Pott’s disease or Pott’sgangrene).● He examined patients with testicular cancer (they were young men).So the two biases against them were that they were now sexuallyactive and that they probably had poor hygiene since they were froma poor background. In the case histories, he found that they had allworked as chimney sweeps at one point in their lives (this professionwas usually left to young boys).● Percivall Pott established that there was a link between the exposureto sut and the development of the cancer. Furthermore, he realizedthat the mutation took time to accumulate as there was an 8-10years period time between the exposure and manifestation.● In this period, many discoveries were the result of the developmentof new technologies such as various microscopes (light microscope –to see larger organelles in cells like nucleus and usually nothingelse, electron microscopes – to see organelles in some detail,scanning electron microscopes and scanning tunneling microscopes).● It started with Robert Hooke’s Micrographia were he detailedvarious things he saw through his microscope. The first thing helooked at was the cork (he saw chambers which he dubbed celluli).He also saw a fungus called mucor and depicted it in Micrographia.● Anton Van Leeuwenhoek was a Dutch scientist (son of a basketmaker) and worked in the shop of a textile merchant. He was good atgrinding lenses to look at whatever he wanted. He looked at a dropof water from a pond and saw a lot of different creatures swimming(such as paramecium, etc.) He looked at red blood cells, ejaculatefrom animals to describe spermatozoa, as well as insects.● Robert Brown looked at plant tissue and found what were referredto as opaque spots (he called them Nucleua; now nucleus).● Cell Theory (Matthias Schleiden and Theodor Schwann). Theywould always see nuclei separated by what looked likecompartmental sections. Each compartment had nucleus. They thenmade the intellectual leap that they were cells. So the differencebetween an elephant and a mouse was in the number of cells. Also,they used a light microscope so they did not even see the plasmamembrane, but only noticed the difference in contrast betweencytoplasm and surrounding medium.● They argued that 1) cells were the fundamental unit of life and that2) all living things are made up of cells.● Rudolph Virchow suggested that all cells originated from previouscells. This was the final tenet of the cell theory.● Eukaryotic cells vs. Prokaryotic cells: Eukaryotic cells have nucleiand internal membrane bound organelles. Different classes ofeukaryotic cells are plant cells, algae, protists, fungi, and animalcells. Plant cells typically have a cell wall, a vacuole andchloroplasts. Algae have flagella and are unicellular. You can alsolook at paramecium (freshwater unicellular organism, can reproduceasexually or sexually). If a paramecium is swimming and hits anobject, it can change direction and move (coordinated cilia).● To study and understand this coordination, a researcher glued aparamecium to the cover of a plate with a film of water and lookedunder a microscope to watch, frame by frame, the orientation of thebeat. It turns out they have mechanosensory channels (gradient ofcalcium concentration) which allow them to respond to stimuli.● Prokaryotes are generally much smaller then eukaryotes and usuallyhave the dimensions of a cylinder (0.5 micrometer to ~ 2 micrometerwhereas eukaryotes can go from 20-30 micrometer with a nucleus of8 micrometer). Prokaryotes have a plasma membrane as well as acapsule, and even a flagellum (work by rotating, are less flexiblethan other flagellum). 1.5 millimeter length of DNA in prokaryote butup to 2 meter length of DNA in eukaryote.● In secretory cells, they have ducts with nuclei far away from theducts to make room for secretory vesicles.● Studies of retroviruses (RNA Viruses) led to many breakthroughs suchas oncology, as well as the establishment of recombinant DNAtechnology, etc.09/05/2012 Notes● The length of the chromosome in the prokaryote can be up to athousand times the length of the cell.● Prokaryotes have a capsule (outer envelope) surrounding thephospholipid bilayer plasma membrane that regulates the passagesof the molecules from
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