Origin of life Flashcards
(46 cards)
What is NASA’s definition of life?
Life is a self-sustained chemical system capable of undergoing Darwinian evolution.
What are the seven pillars of life according to Koshland?
Program, Improvisation, Compartmentalisation, Energy, Regeneration, Adaptability, Seclusion.
What does metabolism-first scenario propose?
Life began with simple metabolic networks before genetic replication evolved.
What does replication-first scenario propose?
Life began with self-replicating molecules before metabolism evolved.
What is the ‘RNA World’ hypothesis?
The idea that early life was based on RNA molecules that could both store information and catalyze reactions.
Why is RNA considered better than DNA for the origin of life?
RNA is more reactive and can have catalytic activity unlike DNA.
What are ribozymes?
RNA molecules capable of catalyzing biochemical reactions.
Who discovered ribozymes?
Thomas Cech and Sidney Altman.
What is abiogenesis?
The process by which life arises naturally from non-living matter.
What was the Miller-Urey experiment?
An experiment simulating early Earth conditions to test organic molecule synthesis.
What conditions were assumed in the Miller-Urey experiment?
Strongly reducing atmosphere with methane, ammonia, hydrogen, and water vapor.
What are hydrothermal vents and why are they important for origin of life?
High-pressure, high-temperature environments with chemical gradients that could support early life.
What is chemical disequilibrium and why is it important for life?
A state where reactants and products are not at equilibrium, allowing energy capture for life processes.
What is the proton-motive force?
An electrochemical gradient across a membrane used to power cellular processes.
Why is compartmentalization important in the origin of life?
It allows maintenance of gradients and separation of reactions, critical for life.
What are protocells?
Simple prebiotic structures with a membrane capable of basic life-like properties.
What is the bottom-up approach to studying the origin of life?
Building up complexity starting from simple molecules.
What is the top-down approach to studying the origin of life?
Identifying the minimal set of genes necessary for life by simplifying organisms.
What organism was used in creating the synthetic minimal cell JCVI-syn3A?
Mycoplasma mycoides.
What are the main chemical elements involved in early biochemistry?
Carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur (CHNOPS).
What does the pentose phosphate pathway suggest about early metabolism?
It indicates early metabolism could have both autotrophic and heterotrophic features.
What does ‘panspermia’ propose?
Life on Earth might have originated from extraterrestrial sources.
What role might meteorites have played in abiogenesis?
Meteorites could have delivered organic molecules to early Earth.
What is non-enzymatic metabolism?
Chemical reactions occurring without the need for enzymes.
