study of any small, usually unicellular living thing or infectious, replicating disease agent (like viruses), and response of host to such replicating disease agent (immunology)
All true life is
cellular (with DNA genome, RNA, ribosomes to make proteins, and cell membranes)
development and differentiation
interaction with environment and other cells
capable of evolving.
Bacteria, protozoans, and other small “animalcules” were discovered in 1673 by
Anton van Leeuwenhoek
showed correlation between reduction of infection in surgery and use of phenol and heat-sterilization to reduce number of bacteria
reported boiling broths in glass flasks and sealing by melting glass neck of flask prevented growth of microbes which colonize broth in open flasks.
showed boiling would prevent microbial growth in swan-necked flask, and that air was a source of microbial colonization of broth. However, some reports of bacterial growth in boiled broth, due to presence of heat-resistant bacterial endospores.
established that culture media must be sterilized by heated steam and high pressure to kill endospores.
Matthias Schleiden (plants) and Theodor Schwann (animals)
proposed organisms are composed of the same basic unit (cells)
theorized all cells arise from division of pre-existing cells
showed correlation between reduction of infection in surgery and use of phenol and heat-sterilization to reduce number of bacteria.
Suspected pathogenic microbe must be present in diseased animals but not in healthy ones.
Microbe must be isolated and grown in pure culture.
When microbe from culture injected into animal, disease results.
Same microbe must be re-isolated from diseased animals.
prepared vaccines against rabies virus and anthrax, using attenuated (enfeebled strains of pathogen, which lost virulence genes)
discovered the antibiotic Penicillin
studied fermentation of wine to ethanol by yeast, organic acids by bacteria- developed pasteurization to preserve wine
examined soil bacteria, discovered autotrophic (CO2-fixing) bacteria which oxidize simple inorganic compounds like ammonia.
discovered bacterial N fixation.
Six elements predominate in living things
Elements responsible for osmotic balance of cells and nerve impulses.
Elements found in enzymes:
atoms share e-
Very strong and stable in solutions of water.
2 atoms may not share electrons equally; nucleus of one atom attracted to shared e- more than other, resulting in slight imbalance of charge.
measure of how great attraction between nucleus of atom and e- in outer shell is. The more different the electronegativities of 2 atoms in a covalent bonds are, the more imbalanced is the charge over molecule (more polar).
Carbon atoms can form bonds with each other, forming
complex chains or polymers.
atoms exchange e-
Strong in solid crystals, but rather weak in water solutions
example is magnesium chloride
Clusters of atoms that interact together in chemical reactions
Name Functional Groups:
Properties of water
O covalently bonded to 2 H atoms
Although shared, e- spend more time on O, less on H, so partial – charge on O, + charges on H (polar molecule)
Polarity of water molecule: interacts with charged atoms (ions) or other polar molecules- a good solvent for polar (hydrophyllic = water loving) molecules like salts.
What happens when a compound dissolves in water? Why does calcium chloride (CaCl2) dissolve readily in water?
Why is H2S a smelly gas while H2O is a pleasant liquid?
What is meant by a hydrophyllic compound vs. a hydrophobic compound? give some examples of each.
What determines how many and what sort of chemical bonds an atom of an element will form?
What sorts of bonds do atoms of carbon form? What sorts of bonds does the element chlorine form? Why does this allow carbon atoms to form the backbone of complex molecules found in living things?
Why isn't argon found in living organisms, even though it makes up 0.9% of earth's atmosphere?