The cell Flashcards
what is spontaneous generation
the idea that life arose from non-living matter
who propose spontaneous generation
aristotle
who was the first to refute spontaneous generation
Francesco redi
what did red predict
that preventing flys from having contact with meat would prevent maggots
Who official disproved spontaneous generation
Louis pasteur
how was Pasteurs experiments different from others
the swan necks allowed outside air in but would trap any microorganisms
what are the tenants of modern cell theory
all cells only come from other cells
cells are the fundamental units of organisms
who was the first to observe nuclei
Robert brown
who was the first to describe chloroplasts and their role in starch formation
Andreas Schimper
what did kontantin mereschkowski suggest
chloroplasts may have originated from ancestral photosynthetic bacteria living symbiotically inside a eukaryotic cell, a similar hypothesis for the nucleus
what is endosymbiotic theory
the theory that mitochondria and chloroplasts arose as a result of prokaryotic cells establishing a symbiotic relationship within a eukaryotic host
what is the first event of endosymbiotic theory
ancestral eukaryote consumed aerobic bacteria that evolved into mitochondria
what is the second
early eukaryote consumed photosynthetic bacteria that evolved into chloroplasts
What is the miasma theory proposed by the greeks
disease originated from particles emanating from decomposing matter such as that in sewage or cesspits
what is germ theory of disease
diseases may result from microbial infection
who noticed mothers who gave birth to doctors and medical students had a higher death rate
Ignaz semmelweis
What did John snow track
cholera outbreaks in London to two specific water sources contaminated by sewage. the first epidemiological study
who instead on hand washing and clean areas for surgery
Joseph lister
what are Koch’s postulates based on
the idea that the cause of a specific disease could be attributed to a specific microbe “one microbe, one disease”
what does cell theory state
the cell is the fundamental unit of life
what is cytoplasm
a gel-like substance composed of water and dissolved chemicals needed for growth
where is cytoplasm found
within the plasma membrane (cell membrane)
what structures are in all cells
cytoplasm
one or more chromosomes
ribosomes
Cytosol
what are ribosomes
organelles used for the production of proteins
what characteristics of prokaryotic cells
they lack a nucleus and generally have a single circular chromosome in a nucleoid
what defines eukaryotic cells
have a nucleus surrounded by a complex nuclear membrane with multiple rod shaped chromosomes with membrane bound organelles
what is coccus
round prokaryotic cell
what is bacillus
rod shaped prokaryote
what is vibrio
curved rod
what is coccobacillus
short rod
what is spirillum
spiral
what is spirochete
long, loose, helical spiral
coccus arrangment
single coccus
diplococcus arrangement
pair of two cocci
what is a tetrad
grouping of four cells in a square
what is streptococcus
chain of cocci
what is staphylococcus
cluster of cocci
what is bacillus
single rod
what is diplobacillus
pair of rods
what is streptobacillus
chain of rods
what is palisade
v or l shaped formation of rods
what maintains morphology of prokaryotic cells
cell wall with cytoskeletal elements
what does the cell wall do
envelopes the cell membrane and protects from osmotic pressure changes
what causes osmotic pressure
differences in the concentration of solutes on opposing sides of a semipermeable membrane
what causes osmotic pressure
differences in the concentration of solutes on opposing sides of a semipermeable membrane
when does water pass a semipermeable membrane
when concentration of solutes is greater on one side of the membrane
what direction does water flow across the membrane
from the side with a lower concentration to a side with higher concentration of solutes until both sides are equal
what is an isotonic medium
when the solute concentrations inside and outside are equal
what is a hypertonic medium
when the solute concentration outside exceeds that inside the cell so water leaves the cell
what is a hypotonic medium
when the solutes on the inside of the cell are higher, so water goes in the cell.
what is tonicity
the degree to which a particular cell is able to withstand changes in osmotic pressure
what cells are better able to withstand changes in osmotic pressure
those with a cell wall
what happens to cells in a hypertonic environment without a cell wall
cells without a cell wall can become dehydrated causing crenation
what is crenation
shriveling of the cell, the plasma membrane contracts and appears scalloped or notched
what happens to cells with a cell wall in a hypertonic environment
they undergo plasmolysis
what happens in plasmolysis
plasma membrane contracts and detaches from the cell wall and there is a decrease in interior volume but the cell wall is intact
what happens to cells without a cell wall in a hypotonic environment
they are more prone to lysis
what happens to cells with a cell wall in a hypotonic environment
the cell wall helps maintain shape for a longer time before lysing