Cells - The Fundamental Units of Life Flashcards
what is the most basic unit of any organism
cells (smallest unit of life)
what makes a cell alive
can divide, grow and take energy from environment
grow and create copies of themselves
definition of cells
membr enclosed units willed with concentrated aqueous solution of chemicals and can grow and create copies
what is the form and function principle
cells are specialized and take on a form that allows them to do their function
what is the language of cells
ATCG: DNA / chemical composition
what is the central dogma
nucleotides in a segment of DNA (gene) transcribed into RNA
translated into amino acids
forms a protein
how is life an autocatalytic process
DNA/RNA provide sequence info used to synthesize prots
prots have catalytic funcitons to synthesize DNA/RNA/prots
creates a self-replicating system
what is cell theory
all living organisms are made up of 1 or + cells
all cells arise from other preexisting cells
if we all cells come from preexisting cells, how do we evolve
mutations: change in amino acid sequence in DNA
how do mutations explain evolution
if mutation is beneficial, its kept
if not, not kept when possible
what are the different types of mutations
silent mutation: no effect on function
deleterious: changes the function
beneficial: will be kept, explains how we adapt to environments
are viruses alive
no, they can grow and divide on their own, but need a host, cant supply their own energy from the environment
who are the 2 pioneers in cell microscopy
Robert Hooke
Antoni can Leeuwenhoek
who was the first to draw a living plant cell and when and how
1880, Eduard Strasburger
hair cell from Tradescantia flower
can see DNA condensing into chromosomes
who worked on cell theory and what else did they do
Schleiden and Schwann 1838-39
systematic study of plant and animal cells with light microscope
what are characteristics of a light microscope
magnify object up to 1000x
method: difraction of light
light is focused into specimen by lenses in the condenser
resolution: 200nm
can look at: cell division
what is the limit of a light microscope
resolution/resolving power: min distance btw 2 adjacent objects for them to be distinguished as 2 separate objects
what affects the resolution
wavelength, (400-700nm)
what is the smallest resolution you can get with a light microscope
2 objects 200nm apart, cant see less than that
what are the characteristics of a transmission electron microscope
method: beam of electrons
resolution: a few nm
requirements: very thin specimen
stained with electron-dense heavy metals
can look at: DNA molecule
what is the order through which the light goes through in a light microscope
light source, condenser lens, glass slide, specimen, objective lens, tube lens, eyepiece, eye, retina
what is the order through which the beam of electrons goes through in a TEM
electron gun, condenser lens, specimen, objective lens, projector lens, viewing screen (photographic film)
what are the characteristics of a scanning electron miscroscope
method: scatters electrons off the surface of samples
can look at: structures on the surface
what order does the electrons go through in SEM
electron gun, condenser lend, beam deflector, objective lens, specimen + scan generator, video screen, detector
limitation: only surface, cant see inside
