life on earth Flashcards
all life is ___ based
carbon
most common elements in living entities
C,O,H,N,P,S
how was carbon formed
in the stars from collision of 3 Helium atoms
robert hooke
termed the word cell
British naturalist and scientist
original old cell theory
1) cell is unit of structure
2) is a distinct entity and a building block in construction or organisms
3) cells form by free cell formation, (spontaneous generation) NO
modern cell theory (6 points)
1) all known living things made up of cells
2) the cell is structural and functional unit of all living things
3) all cells only arise from pre-existing cells
4) cell contain heredity info passed from cell to cell during division
5) all cells basically same in chemical composition
6) all energy flow (metabolism and biochem) of life occurs within cells
3 main categories of life
prokaryota-archaea
prokaryota-eubacteria
eukaryota
life involves
metabolism, heredity and life happens in cells
karyon=___ pro=___ eu=___
nut, before, true
viruses
infectious particles consisting of nucleic acid in protein/ lipid/ carbohydrate coat
viroids
infectious molecules of RNA that cause plant diseases (also in animals)
obelisks
RNA virus like entities in bacteria in human GIT
prions
transmissible abnormal form of normally-occurring protein
biogenesis theory
life arose from pre-existing life, basis seen in abundance of organic molecules in space
abiogenesis theory
life arose from non life on earth
earth is the source of all earth bound life
first life; when, what and where
around 3.8-4 bya, simple prokaryotic cell, shallow water or deep sea vents or clay or ice or moist sediments
how old is earth
approx. 4.6 bya
autotrophic organisms;
convert light energy into chemical energy to make biomass
heterotrophic organisms
use food molecules, ultimately generated by autotrophs, to make energy and biomass
information carriers for life
DNA and RNA
anabolism
building of complex molecules from numerous simple ones
catabolism
break down of complex molecules into simple ones
list the unity of life factors (things that all life has)
- all life is cellular
- life requires input of energy (autotrophic or heterotrophic)
- life has self sustaining chemical reactions (metabolism)
- living things reproduce themselves
- info carriers for life are DNA and RNA
- life evolves (adapts); life is a continuum from first to modern forms
