3rd quarter exam (Gen Bio) Flashcards
the basic building blocks of proteins
Amino acids
the linking together (or polymerization) of small organic molecules (like amino acids) to form larger ones, called biopolymers (like proteins).
Biosynthesis
DNA meaning
Deoxyribonucleic acid
a double-chain biopolymer that consists of two twisted chain-like molecules held together by organic molecules. It stores genetics.
DNA
RNA meaning
Ribonucleic acid
is a single-strand molecule similar to one-half of a DNA strand that transmits genetic info.
RNA
contains the information needed to construct an exact duplicate of the protein molecule.
RNA
is the set of biochemical reactions by which organisms produce and extract food energy.
Metabolism
is anaerobic metabolism - without oxygen.
Fermentation
is aerobic metabolism - with oxygen.
Respiration
process whereby plants use light energy to cause carbon dioxide to react with water.
Photosynthesis
By products of Photosynthesis
Organic substances - carbohydrates
and free oxygen
The solar system coalesced 4.6 b.y. ago from a cloud of cosmic dust and gas. Gravitational compaction caused nuclear fusion to begin in the sun.
Early Earth 4.6 b.y.
(Early earth) gathered into larger clusters to make planets; leftover material formed asteroids and comets.
Planetesimals
Probably molten at first, Earth was battered by repeated impacts of planetesimals. The first atmosphere was stripped away by solar wind or impacts, but was replenished by volcanic eruptions.
Early Earth 4.5 b.y.
As Earth cooled, water vapor in the atmosphere condensed and rained out to form oceans - maybe as early as 4.4 b.y. ago.
Early Earth 4.4 b.y.
Near the end of the intense bombardment period, about 3.8 b.y. ago, Earth still was wracked by meteorite impacts and volcanic eruptions. It was a tough place to make a living.
Early Life 3.8 b.y.
The first life required chemosynthesis of organic compounds - such as amino acids - from inorganic materials like atmospheric gases, to make proteins.
Origin of Life
One hypothesis suggests simple microbes first formed in aerosols - tiny liquid droplets or solid particles suspended in the atmosphere.
Origin of Life
Because of the adverse surface conditions, the most likely place for life to develop might have been at deep ocean thermal springs, protected from meteorite bombardment. Both the raw materials and the heat needed for chemosynthesis would have been available here.
Origin of Life
The first life was microbial.
Origin of Life 3.5 b.y. +?
Meteorite ALH84001 was found in Antarctica in 1984. It is 4.5 b.y. old. Its chemistry is unlike Earth rocks - instead, it is like Mars rocks analyzed by remote landers.
Mars Life? 4.5-3.6 b.y.
In 1996, tiny tube-like structures were discovered
inside the meteorite. Some scientists have interpreted these structures as fossils of microbes - if so, they would be at least 3.6 b.y. old.
Mars Life? 4.5-3.6 b.y.
Chemical sediments from 2.0 to 1.8 b.y. consist of oxygen-poor iron minerals plus oxygen-rich iron minerals
Oxygen Atmosphere 1.8 b.y.
All organisms are composed of cells, a complex grouping of chemical compounds enclosed in a membrane, or porous wall.
Early Life
(Early life) store their DNA in a poorly defined part of the cell, not separated from the cytoplasm - the main body of the cell - by a membrane.
Prokaryotic cells
(Early life) include a distinct nucleus surrounded by a membrane, as well as other membrane-bounded organelles - well defined parts that each have a specific function.
Eukaryotic cells
the earliest and simplest cell forms; many are anaerobic.
Prokaryotic cells
are larger and more complex; most require oxygen.
Eukaryotic cells
bones and other hard parts are replaced by minerals carried in solution by groundwater.
Mineralization
has been replaced by mineralization.
Petrified wood
