Chpt 21-defining life and it's origins Flashcards
define abiotic
physical factors in the environment
define biotic
living components of the environment
what are the seven characteristics of life?
display order harness and use energy reproduce respond to stimuli exhibit homeostasis grow and develop evolve
what is a cell?
the fundamental units of life
define emergent property.
new property that forms when simpler objects associate to increase complexity of the resulting combo
what is meant by the statement “life displays emergent properties?”
the 7 properties of life emerge from much simpler interactions, for example macromolecules interacting to create cellular processes
define abiotic synthesis
mlcls produced in the absence of life, such as the first macromolecules
what was the first experiment to determine the abiotic formation of macromolecules, critical to life?
miller’s reaction chamber experiment
name three macromolecule origin hypothesis
the reducing atmosphere hypothesis, the deep sea vent hypothesis and the extraterrestrial organs hypothesis
define macromolecules and give examples
biologically important mlcls that can be synthesized outside of living cells with an input of E, includes lipids, nucleic acids, proteins and polysaccharides
which macromolecules orgin hypothesis completely PROVES that abiotic production of life’s chemicals is possible?
the ET orgins hypothesis
define polymer
macromolecules formed from the bonding of individual monomers
define monomer
subunits that links together to form polymers during polymerization
what is the monomer of nucleic acids?
nucleotides
what is the monomer of proteins
amino acids
what is the monomer of polysaccharides, such as starch and cellulose
simple sugars
polymers are synthesized by…
dehydration
define enzyme
a protein based catalyst
what is the clay hypothesis?
formation of short nucleic acids and polypeptides can be synthesized on clay surfaces
what is the difference between a reducing atmosphere and an oxidizing one?
A reducing atmosphere is an atmospheric condition in where oxidization is prevented by reducing gases, such as O2 and CO2. whereas an oxidizing atmosphere oxidizes immersed surface compounds, for example, the O2 rich atmosphere on earth.
define selectively permeable
Membranes that selectively allow, impede, or block the passage of atoms and molecules.
what three things do modern life forms need to survive on a microscopic level?
cells, systems to store genetic info and systems to harness energy
define protobiant
abiotically produced organic molecules surrounded by a membrane, act as a bilayer of early lipid spheres
what were lipid spheres
protobiants that allowed for metabolic runs to occur, similar to present day lipid vesicles
how did lipid spheres allow for metabolic runs to occur?
Conc. of mlcls was higher in closed off environment and a greater complexity of molecules was maintained
what is a liposome
self assembly of phospholipids that create a bilayer or vesicle to isolate organic molecules
define the central dogma
the flow of genetic material within a biological system, generally DNA to RNA to proteins
define gene
a unique dna sequence
define ribozymes
an rna based catalyst, part of the biochem machinery of all cells,catalyzations lead to their own synthesis
Put the following in evolutionary order: protein rna dna
rna protein dna
why is dna better than rna for storing info (3 reasons)
dna is more stable, base uracil replaces thymine, dna is double stranded
how could alkaline hydrothermal vents have been a free source of E for early organisms?
they were constantly out of equilibrium because of their low conc. of H+ compared to the ocean, so the H+ conc. gradient could synthesize ATP
define anerobic
without O2
What processes take place in an Energy-coupling reaction
oxidization and reduction
what characteristics of life do viruses violate
they lack the ability to reproduce on their own
Why would the accumulation of organic material on early Earth be important for the formation of protobionts?
It would allow the chance assembly of molecules into membrane-bound aggregations.
As the planet’s atmosphere slowly accumulated O2, starting about 3 billion years ago, what pre-organelle-like structure began to develop in the form of aerobic prokaryotes ingested by other, predatory prokaryotes?
Mitochondria
What is believed to have led to the formation of tissues and organs in complex eukaryotes?
cells that are specialized
