micro ch 3

Question Answer
spontaneous generation the notion that life can arise from nonliving matter
pneuma "vital heat"
Aristotle proposed that life arose from nonliving material if the material contained pneuma (“vital heat”).
Jan Baptista van Helmont 17th century Flemish scientist, proposed that mice could arise from rags and wheat kernels left in an open container for 3 weeks.
Francesco Redi performed an experiment in 1668 that was one of the first to refute the idea that maggots (the larvae of flies) spontaneously generate on meat left out in the open air.
John Needham In 1745, he briefly boiled broth infused with plant or animal matter, hoping to kill all preexisting microbes
Lazzaro Spallanzani heated jars, but boiled long enough unlike needham, prooved sealed flasks remained clear, without any signs of spontaneous growth, unless the flasks were subsequently opened to the air
Robert Hooke was the first to describe cells based upon his microscopic observations of cork
Matthias Schleiden In 1838, made extensive microscopic observations of plant tissues, believed that cells formed through crystallization, rather than cell division. (100 years after robert hooke)
Theodor Schwann in 1839, after a conversation with Schleiden, Schwann realized that similarities existed between plant and animal tissues. This laid the foundation for the idea that cells are the fundamental components of plants and animals.
Robert Remak n 1852, a prominent neurologist and embryologist, published convincing evidence that cells are derived from other cells as a result of cell division. Known today as the modern cell theory.
Rudolf Virchow "father of pathology" one of the first to determine the causes of various diseases by examining their effects on tissues and organs.
Robert Brown first to describe observations of nuclei, which he observed in plant cells.
Andreas Schimper. first to describe the chloroplasts of plant cells, identifying their role in starch formation during photosynthesis and noting that they divided independent of the nucleus.
Konstantin Mereschkowski in 1905, "endosymbiotic hypothesis"that chloroplasts may have originated from ancestral photosynthetic bacteria living symbiotically inside a eukaryotic cell. Explained how eukaryotic cells evolved from ancestral bacteria.
Ivan Wallin furthered mereschkowski info to examine the similarities between mitochondria, chloroplasts, and bacteria
endosymbiotic theory The theory that mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship within a eukaryotic host
miasma theory ancient greeks thought that disease originated from particles emanating from decomposing matter, such as that in sewage or cesspits.
Girolamo Fracastoro "germ theory of disease" in his essay De Contagione et Contagiosis Morbis, that seed-like spores may be transferred between individuals through direct contact, exposure to contaminated clothing, or through the air.
germ theory of disease diseases may result from microbial infection.
Cell theory That living organisms are made up of cells. Cells are the basic unit of structure in all organisms and also the basic unit of reproduction.
John Snow is known as the Father of epidemiology
The ____________ theory states that disease may originate from proximity to decomposing matter and is not due to person-to-person contact. miasma
The scientist who first described cells was Robert Hooke
cytoplasm a gel-like substance composed of water and dissolved chemicals needed for growth), which is contained within a plasma membrane (also called a cell membrane or cytoplasmic membrane)
chromosomes contain the genetic blueprints of the cell
ribosomes organelles used for the production of proteins.
osmotic pressure occurs because of differences in the concentration of solutes on opposing sides of a semipermeable membrane.
osmosis Diffusion of water from low concentration (more water) to low concentration (more water) to equal out.
isotonic medium the solute concentrations inside and outside the cell are approximately equal, so there is no net movement of water across the cell membrane.
hypertonic medium solute concentration outside the cell exceeds that inside the cell, so water diffuses out of the cell and into the external medium
hypotonic medium solute concentration inside the cell exceeds that outside of the cell, so water will move by osmosis into the cell. This causes the cell to swell and potentially lyse, or burst.
tonicity The degree to which a particular cell is able to withstand changes in osmotic pressure
crenation shriveling of the cell; cells that lack a cell wall can become dehydrated.
plasmolysis the plasma membrane contracts and detaches from the cell wall, and there is a decrease in interior volume, but the cell wall remains intact, thus allowing the cell to maintain some shape and integrity for a period of time
Lysis Swelling of the cell; possible explosion of the cell
haploid not paired
plasmids prokaryote cells; small, circular, double-stranded DNA molecules; often carry genes that confer advantageous traits such as antibiotic resistance
inclusions some prokaryotic cells have the ability to store excess nutrients within cytoplasmic structures ; store glycogen and starches which can be used for energy.
Volutin granules staining characteristics, are inclusions that store polymerized inorganic phosphate that can be used in metabolism and assist in the formation of biofilms;
microbes containing volutin granules archaea Methanosarcina, the bacterium Corynebacterium diphtheriae, and the unicellular eukaryotic alga Chlamydomonas.
endospores structures that essentially protect the bacterial genome in a dormant state when environmental conditions are unfavorable.
germination when living conditions improve, endospores undergo germination and reenter a vegetative state