Chapter 1 (scientist quiz) Flashcards
(21 cards)
2 Theories where the cell originated
- spontaneous generation
- biogensis
Spontaneous Generation
- also called abiogenesis
- the idea that cells can develop from non-living things
Biogenesis
-the belief that living cells came from pre-existing living cells
Aristotle (BCE)
- worked in ancient grease
- used observation (no experiment)
- spontaneous generation
- comes directly from 4 elements (Earth, Fire, Water, Air)
Van Helmont (1600’s)
- worked in Belgium
- dirty shirt+wheat grains produced mice
- spontaneous generation
Francesco Redi
- Italian scientist
- used one of the first controlled experiments
- jar A-rotting meat left uncovered in jar (maggots & flies appear)
- jar B-rotting meat covered with cloth (nothing appear)
John Needham (1748)
- English scientist
- flask A-meat broth (non-living) is boiled for a short time (1 min) & left uncovered in a jar
- turned cloudy
- flask B-same process but seal with a cork
- turned cloudy
- spontaneous generation
- poor seal or not born long enough?
Lazzaro Spallanzani (1776)
- Itallian scientist
- questioned Needham’s expiriment (boiling time, better glass seal)
- flask A-meat broth (non-living) is boiled (1H) & glass sealed in a flask
- turned cloudy
- flask B-meat broth (non-living) boiled (1H) & glass sealed in a flask
- remained clear
- biogenesis
- critics said by sealing the flask it eliminated a vital force
Louis Pasteur (1859)
- French scientist
- designed S-shaped flask
- allowed air in but microorganisms settles in the bend
- flask A-S-shaped glass kept upright
- no organisms (clear)
- flask B-S-shaped glass is tipped or broken
- microorganisms (cloudy)
- biogenesis settled debate
- created a paradigm shift in science
Stanley Miller & Harold Urey (1953)
- American scientists
- placed water, methane, hydrogen & ammonia in a flask…representing ancient Earth’s ocean
- ran electrical sparks through this mixture…representing ancient Earth’s atmosphere
- from this non-living mixture they were able t produce amino acids- the building blocks for cells (life)
- spontaneous generation
Development of the Cell Theory
Development of the Cell Theory
-the invention of the microscope was important in realizing that living cells come from other living cells & allowed for development of cell theory
Who made the microscope?
Dutch eyeglass maker (1590)
Robert Hook (1600’s)
- English scientist
- built a compound microscope (double lens) 60x large
- first person to apply the word “cell” to a living structure
- observed dead cork cells
- boxes looked like cubicles where monks prayed called cells
Anton Van Leeuwenhoek (1600’s)
- Dutch scientist
- built a single lens microscope
- greater mag 270x
- improved clarity & magnification because of better glass making & lens quality
- first to discover microorganisms (animalcules) including bacteria
- microorganism: single cell organism
- pond water & wife’s teeth sample
Robert Brown (1831)
- Scottish scientist
- first to identify & name nucleus as part of the living cell
- observed orchids
Matthias Schleiden (1838)
- German botanist
- states all parts of plants are made of cells
Theodor Schewann (1839)
- German zoologist
- states all parts of animals are made of cells
Hugo Van Mohl (1846)
- German biologist
- cells are made of cytoplasm surrounded by a membrane
William Henery (1856)
-developed a purple staining specimen to stain cells providing contrast
Rudolph Virchow (1858)
- developed final form of cell theory
- 4 points
1. all living organisms are made up of 1 or more cells
2. cells are the basic units of structure & functions in all organisms
3. all cells come from pre-existing cells
4. in multicellular organisms the activity &health of the whole organism depends on the activity & health of the entire cell
