A2.1 Origin of Cells Vocabulary

cell theory

idea that all living things are composed of cells, cells are the basic units of structure and function in living things, and new cells are produced from existing cells

inorganic compounds

do not usually contain carbon, except for carbon dioxide

carbon compounds

organic compounds that contain carbon

hydrocarbons

molecules made up of long chains of carbon and hydrogen bonded together

primordial soup

water based sea of simple organic molecules that was the source of life on Earth

non-reducing environment

lack adequate hydrogen for bonding and would not produce simple carbon compounds

reducing environment

describes the early Earth atmosphere where electron donors were very prevalent (organic molecules could form spontaneously)

vesicle

fatty acids form small, cell-sized double-layer bubbles when added to water (may have been first protocell)

compartmentalization

the development of a boundary around a vesicle necessary for the formation of the first cell

last universal common ancestor

an unknown ancestor that all living things evolved from (also called LUCA)

fossils

the remains and/or traces of past life on Earth

absolute dating

mathematically calculating the age of a fossil using the amount of of an isotope in a fossil and the known half-life value of the isotope

relative dating

utilizes sediment layers of the Earth and index fossils to determine a fossil's age

index fossil

fossils of he same gae that are found in strata in different parts of the world

hydrothermal vents

places where hot water emanates from beneath the ocean floor